Improvements to roof support cribs

Abstract

The present disclosure provides a crib element (10) for assembly into a crib column for supporting a mine tunnel roof, the crib element (10) comprising an elongate body (12) configured to stack on and couple to other like elongate bodies to form a perimeter of a hollow column, and coupling elements (22) disposed at an end of the elongate body (12) to couple with a cooperating coupling element on a like elongate body, wherein the coupling element (22) connects its elongate body to another like elongate body at an angle other than perpendicular. The elongate body (12) may be formed from a polymer and include internal voids (32) for reducing mass. The coupling elements (22) may comprise notches for receiving a portion of the like elongate body. The crib element (10) may include an internal plate (60) disposed midway between top and bottom faces.

Description

[0001] IMPROVEMENTS TO ROOF SUPPORT CRIBS

[0002] FIELD OF INVENTION

[0003] The present disclosure relates generally to mine tunnel roof support systems, and more particularly to crib elements with coupling features for assembly into hollow columnar supports.

[0004] BACKGROUND

[0005] Mining operations involve the extraction of minerals and natural resources from underground tunnels and shafts, requiring extensive excavation work using heavy machinery and skilled personnel. The underground environment presents numerous challenges, including the maintenance of structural stability in excavated areas where the natural support provided by the surrounding rock and earth has been removed.

[0006] Underground mining tunnels and shafts are subject to various geological pressures and environmental conditions that can compromise their structural integrity. The excavation process creates voids that must be supported to prevent collapse and ensure worker safety. Ground conditions, water infiltration, temperature variations, and the dynamic nature of mining operations all contribute to the demanding environment in which support systems must function.

[0007] Roof support systems in mining operations have traditionally relied on various structural elements to maintain tunnel stability. These support systems must be capable of withstanding substantial loads while being practical to install and maintain in the confined spaces typical of underground mining operations. The effectiveness of roof support directly impacts both operational safety and mining productivity.

[0008] Conventional support materials have included timber-based systems, which have been used extensively in mining applications due to their availability and workability. However, natural materials can be subject to variability in their physical properties, dimensional changes due to moisture absorption, and degradation over time when exposed to harsh underground conditions. Additionally, the weight and handling characteristics of traditional support materials can present logistical challenges in underground installations.

[0009] The mining industry continues to seek improvements in support system design that can address the limitations of existing approaches while providing reliable performance in demanding underground environments. Factors such as material consistency, ease of installation, resistance to environmental conditions, and predictable load-bearing characteristics are considerations in the development of enhanced roof support solutions.

[0010] SUMMARY

[0011] According to an aspect of the present disclosure, a crib element for assembly into a crib column for supporting a mine tunnel roof is provided. The crib element comprises an elongate body configured to stack on and couple to other like elongate bodies to form a perimeter of a hollow column. The crib element further comprises one or more coupling elements disposed at an end of the elongate body to couple with a cooperating coupling element on a like elongate body. The coupling element is configured to connect its elongate body to another like elongate body at an angle other than perpendicular.

[0012] This configuration enables the formation of non-rectangular hollow columns such as hexagonal, pentagonal, or triangular cross-sections, which can provide enhanced structural stability and load distribution compared to conventional square timber cribs. The angled coupling arrangement allows for more efficient use of materials and improved resistance to lateral forces in underground mining environments.

[0013] According to other aspects of the present disclosure, the crib element may include one or more of the following features. The coupling element may comprise a notch for receiving a portion of the like elongate body to couple it to form a peripheral arc of the hollow column.

[0014] The notch configuration provides a mechanical interlock that distributes loads across a larger contact area compared to simple end-to-end connections, reducing stress concentrations and improving the structural integrity of the assembled column.

[0015] According to other aspects of the present disclosure, there may be two notches at each end of the elongate body.

[0016] The dual notch arrangement at each end provides redundant coupling points that enhance the stability of the connection and allow for more secure assembly of the hollow column structure. According to other aspects of the present disclosure, the notches at each end may be formed on opposing sides of the elongate body.

[0017] This opposing arrangement ensures balanced load transfer between adjacent crib elements and prevents rotational movement that could compromise the structural integrity of the assembled column.

[0018] According to other aspects of the present disclosure, the elongate body may be formed from a polymer.

[0019] Polymer construction provides consistent material properties, resistance to moisture absorption and decay, reduced weight for easier handling, and improved dimensional stability compared to traditional timber materials.

[0020] According to other aspects of the present disclosure, the polymer may be selected from the group consisting of polypropylene, polyethylene, acetal, polycarbonate, ABS, PPS, TPU, PEEK, and acrylic.

[0021] These polymer materials offer varying combinations of strength, durability, chemical resistance, and cost-effectiveness, allowing selection of the most appropriate material for specific mining environment conditions and load requirements.

[0022] According to other aspects of the present disclosure, the crib element may further comprise a network of internal voids for reducing mass of the elongate body.

[0023] The internal void structure reduces the overall weight of the crib element while maintaining structural strength, facilitating easier manual handling and transportation in confined underground spaces, and reducing material costs.

[0024] According to other aspects of the present disclosure, the internal voids may comprise a regular array of honeycomb voids extending from one wall of the elongate body to another wall.

[0025] The honeycomb void pattern provides an optimal strength-to-weight ratio by distributing loads through the remaining material structure while maximising material removal, resulting in a lightweight yet structurally robust crib element.

[0026] According to other aspects of the present disclosure, the crib element may further comprise an internal plate disposed midway between a top face and a bottom face of the elongate body, wherein the internal plate closes the honeycomb voids at a midline of the elongate body. The internal plate provides structural reinforcement at the midline, enables the creation of halfheight elements by cutting along this plane, and ensures a closed surface when the element is divided for use as a top capping piece in the column assembly.

[0027] According to other aspects of the present disclosure, the coupling element may be configured to connect the elongate body to the like elongate body at an angle of approximately 120 degrees to facilitate formation of a hexagonal hollow column.

[0028] The 120-degree coupling angle creates a hexagonal column configuration that provides enhanced structural stability and load-bearing capacity compared to square columns, while distributing forces more evenly around the perimeter of the hollow structure.

[0029] According to another aspect of the present disclosure, a crib element for assembly into a crib column for supporting a mine tunnel roof is provided. The crib element comprises an elongate body configured to stack on and couple to other like elongate bodies to form a perimeter of a hollow column. The crib element further comprises one or more coupling elements disposed at an end of the elongate body to couple with a cooperating coupling element on a like elongate body. The crib element further comprises a polymer material with a plurality of internal voids for reducing mass of the elongate body.

[0030] This combination of polymer construction with internal voids provides a lightweight, durable alternative to traditional timber cribs that maintains structural performance while offering improved handling characteristics and resistance to environmental degradation in underground mining conditions.

[0031] According to other aspects of the present disclosure, the crib element may include one or more of the following features. The polymer material may be formed by a moulding or additive manufacturing process.

[0032] Manufacturing through moulding or additive processes enables precise control of dimensions and internal void structures, consistent material properties across production batches, and the ability to create complex internal geometries that would be difficult or impossible to achieve with traditional materials.

[0033] According to other aspects of the present disclosure, the plurality of internal voids may comprise a regular array of honeycomb voids extending between opposing walls of the elongate body. The regular honeycomb array provides predictable structural behaviour and load distribution characteristics, enabling accurate engineering calculations for column capacity and ensuring consistent performance across multiple crib elements.

[0034] According to other aspects of the present disclosure, the crib element may further comprise an internal plate disposed midway between a top face and a bottom face of the elongate body, wherein the internal plate closes the honeycomb voids at a central plane of the elongate body.

[0035] The central plate configuration allows for inventory rationalisation by enabling a single component design that can be cut to create both full-height and half-height elements, reducing manufacturing complexity and storage requirements.

[0036] According to other aspects of the present disclosure, the coupling elements may comprise notches angled at other than perpendicular and disposed at each end and on top and bottom faces of the elongate body.

[0037] The angled notch arrangement on multiple faces provides secure interlocking in both horizontal and vertical directions, creating a stable three-dimensional assembly that resists displacement under load and maintains column integrity.

[0038] According to another aspect of the present disclosure, a method of forming a crib component for assembly into a hollow crib column is provided. The method comprises forming a first elongate crib element from a moulding or additive process, the first elongate crib element including a polymer material with a plurality of internal voids for reducing mass and coupling notches angled at other than perpendicular and disposed at each end and on top and bottom faces of the elongate crib element. The method further comprises cutting the first crib element along a midway point between top and bottom faces to provide a second half-component which can fit between other first full crib elements for providing a flush and flat upper crib columnar roof surface.

[0039] This manufacturing method enables inventory rationalisation by producing multiple component types from a single manufactured element, reducing production complexity and storage requirements while ensuring proper fit and finish of the assembled column structure.

[0040] According to other aspects of the present disclosure, the method may include one or more of the following features. The first elongate crib element may further comprise an internal plate disposed at the midway point between the top and bottom faces, such that cutting along the midway point provides a closed surface on the second half-component. The internal plate ensures that a cut half-component presents a finished surface suitable for contact with the mine roof, eliminating the need for additional finishing operations and ensuring proper load distribution at the column-roof interface.

[0041] According to other aspects of the present disclosure, the plurality of internal voids may comprise a regular array of honeycomb voids extending from the top face to the internal plate and from the bottom face to the internal plate.

[0042] This void arrangement ensures that both the full element and the cut half-element maintain their lightweight characteristics and structural integrity, with the internal plate providing closure for the void structure in the half-element.

[0043] According to other aspects of the present disclosure, the coupling notches may be configured to connect the first elongate crib element to like elongate crib elements at an angle of approximately 120 degrees to facilitate formation of a hexagonal hollow crib column.

[0044] The 120-degree coupling configuration in the manufacturing method ensures that the resulting components will assemble into a structurally efficient hexagonal column that provides enhanced load-bearing capacity and stability compared to conventional square timber cribs.

[0045] According to other aspects of the present disclosure, the polymer material may be selected from the group consisting of polypropylene, polyethylene, acetal, polycarbonate, ABS, PPS, TPU, PEEK, and acrylic, and the moulding or additive process may comprise injection moulding or 3D printing.

[0046] The specified materials and manufacturing processes provide flexibility in selecting the most appropriate combination of material properties and production methods based on performance requirements, production volumes, and cost considerations for specific mining applications.

[0047] The foregoing general description of the illustrative embodiments and the following detailed description thereof are merely exemplary aspects of the teachings of this disclosure and are not restrictive. BRIEF DESCRIPTION OF FIGURES

[0048] Non-limiting and non-exhaustive examples are described with reference to the following figures.

[0049] Figure 1 illustrates an isometric view of a crib element for assembly into a crib column, according to aspects of the present disclosure.

[0050] Figure 2 depicts a plan view of the crib element of Figure 1, according to aspects of the present disclosure.

[0051] Figure 3 illustrates an outside elevation view of the crib element of Figure 1, according to aspects of the present disclosure.

[0052] Figure 4 depicts an isometric sectional view of the crib element showing internal features, according to aspects of the present disclosure.

[0053] Figure 5 illustrates a sectional isometric view of an elongate body with internal structural features, according to aspects of the present disclosure.

[0054] Figure 6 depicts a hollow column formed by a stack of coupled crib elements, according to aspects of the present disclosure.

[0055] Figure 7 illustrates a plan view of a hollow hexagonal crib column, according to aspects of the present disclosure.

[0056] Figure 8 depicts a plan view of another hollow column with coupling notches disposed toward each end, according to aspects of the present disclosure.

[0057] Figs. 9a-9e illustrate different arrangements of internal void patterns for crib elements, according to aspects of the present disclosure.

[0058] Figure 10 depicts an isometric view of a triangular prism crib assembly, according to aspects of the present disclosure.

[0059] Figure 11 illustrates a schematic view of a testing arrangement for evaluating crib assembly strength, according to aspects of the present disclosure.

[0060] Figure 12 depicts a photograph of a hexagonal crib assembly positioned within a test rig, according to aspects of the present disclosure. Figure 13 illustrates a photograph showing a crib assembly after undergoing load testing, according to aspects of the present disclosure.

[0061] Figure 14 depicts a graph showing load versus actuator position during crib assembly testing, according to aspects of the present disclosure.

[0062] Figure 15 illustrates an isometric view of a rectangular crib element with honeycomb internal structure, according to aspects of the present disclosure.

[0063] Figure 16 depicts a plan view of a rectangular packer or shim with hexagonal-shaped recesses, according to aspects of the present disclosure.

[0064] DETAILED DESCRIPTION

[0065] The following description sets forth exemplary aspects of the present disclosure. It should be recognised, however, that such description is not intended as a limitation on the scope of the present disclosure. Rather, the description also encompasses combinations and modifications to those exemplary aspects described herein.

[0066] The present disclosure relates to polymer-based crib elements for mine tunnel roof support applications. Mining operations may require structural support systems to maintain tunnel integrity and provide safe working conditions for personnel and equipment. Traditional wooden crib systems may present challenges including variable material properties, susceptibility to moisture absorption, potential for decay in underground environments, and inconsistent load-bearing capacity.

[0067] The disclosed technology addresses these challenges through modular crib elements that may be manufactured from polymer materials. The crib elements may be configured to couple together through specialised connection mechanisms that allow assembly at non-perpendicular angles. This angular coupling capability may enable the formation of hollow columnar support structures with polygonal cross-sections, such as hexagonal configurations.

[0068] The polymer-based crib elements may incorporate internal void networks designed to reduce overall mass while maintaining structural integrity. These internal voids may be arranged in regular patterns, such as honeycomb configurations, that distribute throughout the interior of each crib element. The void networks may provide weight reduction benefits that facilitate handling and transportation while preserving the load-bearing characteristics needed for mine roof support applications. The modular design approach may allow for standardised manufacturing processes and simplified inventory management. Individual crib elements may be produced through moulding or additive manufacturing techniques, providing consistent dimensional accuracy and material properties. The polymer construction may offer resistance to moisture absorption and environmental degradation that can affect traditional wooden crib systems.

[0069] The coupling mechanisms may enable field assembly of crib columns without specialised tools or fasteners. The angular coupling configuration may allow multiple crib elements to connect in predetermined geometric arrangements that form stable hollow support structures. These hollow configurations may provide load distribution characteristics while reducing material usage compared to solid support columns.

[0070] Referring to Figure 1, a crib element 10 may be provided for assembly into a crib column for supporting a mine tunnel roof. The crib element 10 may include an elongate body 12 configured to stack on and couple to other like elongate bodies to form a perimeter of a hollow column. The elongate body 12 may extend longitudinally and may be dimensioned to provide structural support while maintaining manageable weight characteristics for field handling.

[0071] The elongate body 12 may include a top face 19 and a bottom face 18 that define upper and lower surfaces of the crib element 10. These faces may provide contact surfaces for stacking multiple crib elements in vertical arrangements. The top face 19 and bottom face 18 may be configured to distribute loads across the full width of the elongate body 12 when crib elements are assembled into columnar configurations.

[0072] As shown in Figure 1, the crib element 10 may include one or more coupling elements disposed at ends of the elongate body 12. The coupling elements may comprise coupling notches 22 configured to couple with cooperating coupling elements on like elongate bodies. Each coupling notch 22 may include notch walls 23 that define the geometry of the coupling interface. The notch walls 23 may be angled to guide connection with other crib elements at angles other than perpendicular, enabling formation of polygonal hollow column configurations.

[0073] The coupling arrangement may include top notches 24 and bottom notches 26 positioned at the ends of the elongate body 12. In some cases, there may be two notches at each end of the elongate body 12, with the notches at each end formed on opposing sides of the elongate body 12. The top notches 24 may be cut down 25% through from the top face 19 so that when coupled the top surfaces may be flush with each other. Similarly, the bottom notches 26 may be cut upwards 25% from the bottom face 18 so that bottom faces may be flush with each other for broad load distribution across the contact surfaces.

[0074] The elongate body 12 may incorporate radiused ends 27 at the terminal portions of the crib element 10. The radiused ends 27 may reduce stress concentrations that could otherwise occur at sharp comers during loading conditions. The radiused ends 27 may have radii of 5mm, 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, or 40mm depending on the specific application requirements and stress distribution considerations.

[0075] With continued reference to Figure 1, the internal structure of the crib element 10 may include a network of voids designed to reduce mass while maintaining structural integrity. The internal structure may comprise a top honeycomb section 33 and a bottom honeycomb section 34 that provide lightweight construction. These honeycomb sections may be separated by a midline plate 60 that extends along a longitudinal plane 66 through the centre of the elongate body 12. The midline plate 60 may provide structural continuity between the upper and lower honeycomb sections while creating a defined separation plane within the crib element 10.

[0076] Referring to Figure 2, the crib element 10 may be viewed in plan to show the configuration of the elongate body 12. The elongate body 12 may extend between a first end 14 and a second end 15, defining the longitudinal extent of the crib element 10. The coupling notches 22 may be disposed at each end of the elongate body 12 to provide connection interfaces for assembly with like crib elements.

[0077] The elongate body 12 may include an internal wall 11 and a perimeter wall 30 that define the structural boundaries of the crib element 10. The internal wall 11 may form part of the inner surface when multiple crib elements are assembled into a hollow column configuration. The perimeter wall 30 may provide the outer structural boundary of the elongate body 12 and may contribute to the overall strength and rigidity of the crib element 10.

[0078] As shown in Figure 2, the elongate body 12 may contain a series of honeycomb voids 32 arranged in a regular pattern between the internal wall 11 and the perimeter wall 30. The honeycomb voids 32 may form a network structure that reduces the mass of the elongate body 12 while maintaining structural integrity. The honeycomb voids 32 may extend across the width of the elongate body 12 and may be arranged in a hexagonal pattern that provides efficient space utilisation and load distribution characteristics.

[0079] The bottom face 18 may extend along the length of the elongate body 12 from the first end 14 to the second end 15. The bottom face 18 may provide a contact surface for stacking arrangements and may distribute loads across the full length of the crib element 10 when assembled into columnar configurations.

[0080] The coupling notches 22 may be positioned at various distances from the first end 14 and second end 15 depending on specific application requirements. In some cases, the coupling notches 22 may be set at distances of 25mm, 50mm, 75mm, or 100mm from the ends of the elongate body 12. The positioning of the coupling notches 22 may affect stress distribution within the crib element 10 and the assembled column structure under roof loading conditions.

[0081] The elongate body 12 may have dimensional characteristics that vary according to application requirements. The length of the elongate body 12 may range between 350mm and 1500mm. In some cases, the elongate body 12 may have lengths of 450mm, 500mm, 550mm, 600mm, 650mm, 700mm, 750mm, 800mm, 850mm, 900mm, 1000mm, 1100mm, 1200mm, 1300mm, or 1400mm. The coupling notches 22 may have a width of 75.5mm to accommodate walls of like crib elements having a 75mm width, providing proper fit and engagement between coupled elements.

[0082] The mass characteristics of the crib element 10 may depend on the length, wall thickness, height, and width dimensions. In some cases, the crib element 10 may have a mass of approximately 5kg, 6kg, 7kg, 8kg, 9kg, or 10kg. The mass may be influenced by the internal void structure, with the honeycomb voids 32 contributing to weight reduction while maintaining the structural properties needed for mine roof support applications.

[0083] Referring to Figure 3, an outside elevation view of the crib element may show the elongate body 12 in a side profile configuration. The elongate body 12 may include coupling notches 22 positioned at the ends of the structure to provide connection interfaces with like crib elements. The coupling arrangement may include a top notch 24 positioned at the upper portion of the elongate body 12 and a bottom notch 26 positioned at the lower portion.

[0084] The midline plate 60 may extend horizontally through the centre of the elongate body 12, dividing the structure into upper and lower sections. The midline plate 60 may provide structural continuity across the width of the elongate body 12 and may serve as a reinforcing element that enhances the axial response characteristics of the crib element under loading conditions. The midline plate 60 may close internal voids within the crib element at the central plane, creating a defined separation between upper and lower void regions.

[0085] The midline plate 60 may have a thickness that varies according to structural requirements and manufacturing considerations. In some cases, the midline plate 60 may have a thickness of 1mm, 2mm, 3mm, 4mm, 5mm, or 6mm. The thickness of the midline plate 60 may influence the structural properties of the crib element and may affect the load distribution characteristics when the crib element is subjected to compressive forces.

[0086] The crib element may be configured with symmetrical geometry about a central longitudinal plane that coincides with the midline plate 60. This symmetrical configuration may enable the crib element to be cut along the central longitudinal plane to create half components. The cutting operation may divide a full-height crib element into two half-height components that may be used in assembly configurations where reduced height elements are needed.

[0087] When the crib element is cut along the central longitudinal plane, the midline plate 60 may provide a closed surface on the resulting half component. This closed surface may present a flat interface that can contact roof surfaces or other structural elements in the assembled crib column. The symmetrical design and central cutting capability may provide inventory management benefits by allowing a single component design to serve multiple assembly functions within the crib system.

[0088] Referring to Figure 4, an isometric sectional view of a crib element may reveal internal structural features that contribute to the lightweight design while maintaining load-bearing capacity. The crib element may include an internal wall 11 that forms part of the inner boundary when multiple crib elements are assembled into hollow column configurations. The bottom face 18 may provide a contact surface for stacking arrangements and load distribution.

[0089] The coupling features may include a top notch 24 and a bottom notch 26 positioned at the ends of the crib element. The notch walls 23 may define the geometry of the coupling interfaces and may be angled to facilitate connection with like crib elements at predetermined angles. A radiused end 27 may be provided at the terminal portion of the crib element to reduce stress concentrations during loading conditions.

[0090] As shown in Figure 4, the internal structure may comprise honeycomb voids 32 arranged in a regular pattern between the walls of the crib element. The honeycomb voids 32 may extend from one wall of the elongate body to another wall, creating a network structure that reduces mass while maintaining structural integrity. The midline plate 60 may extend through the centre of the crib element, dividing the honeycomb voids 32 into upper and lower sections. The midline plate 60 may close the honeycomb voids 32 at a midline of the elongate body, providing structural continuity and creating defined void regions above and below the central plane. With continued reference to Figure 4, the regular array of honeycomb voids 32 may extend between opposing walls of the elongate body. The honeycomb voids 32 may be arranged in a hexagonal pattern that provides efficient space utilisation while distributing structural loads throughout the crib element. The midline plate 60 may be disposed midway between the top face and bottom face of the elongate body, creating a central plane that closes the honeycomb voids 32 and provides reinforcement across the width of the structure.

[0091] Referring to Figure 5, a sectional isometric view may show an elongate body 666 with internal structural features configured for mass reduction. The elongate body 666 may include a coupling notch 22 positioned at an end of the structure to provide connection capability with like crib elements. The internal wall 11 may form part of the structural boundary of the elongate body 666.

[0092] The midline plate 60 may extend through the centre of the elongate body 666, dividing the structure into upper and lower sections. The honeycomb voids 32 may be arranged in a regular pattern between the internal wall 11 and the outer surfaces of the elongate body 666. The honeycomb voids 32 may extend from both the top and bottom faces toward the midline plate 60, creating a lightweight internal structure within the elongate body 666.

[0093] The network of internal voids may provide various configurations for reducing mass of the elongate body while maintaining structural properties. In some cases, the internal voids may comprise a random network structure that distributes throughout the interior of the crib element. The random network structure may provide weight reduction benefits while offering different load distribution characteristics compared to regular void patterns.

[0094] The internal structure may include a lattice framework inside the elongate body that provides structural support while reducing overall mass. The lattice framework may comprise interconnected structural elements that distribute loads throughout the crib element while creating void spaces that reduce material usage and weight.

[0095] In some configurations, the elongate body may be hollow with a single void inside disposed between spaced apart elongate body walls. The single void configuration may provide a simplified internal structure that reduces mass while maintaining the structural integrity needed for mine roof support applications. The spaced apart walls may provide the structural framework that supports compressive loads while the internal void reduces the overall weight of the crib element. The coupling mechanism may enable crib elements to connect at predetermined angles that facilitate formation of hollow columnar structures with various polygonal cross-sections. The coupling notches 22 may be configured with angled geometries that guide connection between adjacent crib elements at angles other than perpendicular to the longitudinal axis of each elongate body 12.

[0096] The coupling notches 22 may include angled notch walls that define the connection geometry between adjacent crib elements. The angled configuration of the coupling notches 22 may allow the elongate body 12 to connect to like elongate bodies at specific angular relationships that determine the final cross-sectional shape of the assembled hollow column. The angular coupling capability may eliminate the need for additional fasteners or connection hardware during field assembly operations.

[0097] In some cases, the coupling notches 22 may be configured to connect the elongate body 12 to like elongate bodies at an angle of approximately 120 degrees. The 120-degree angular connection may facilitate formation of a hexagonal hollow column when six crib elements are assembled together. The hexagonal configuration may provide structural stability while creating a hollow interior space that reduces material usage compared to solid support columns.

[0098] The top notches 24 and bottom notches 26 may be angled at other than perpendicular and may be disposed at each end and on the top face 19 and bottom face 18 of the elongate body 12. The angled configuration of the top notches 24 and bottom notches 26 may enable proper alignment and engagement between stacked crib elements while maintaining the predetermined angular relationships needed for polygonal column formation.

[0099] The coupling mechanism may accommodate various angular configurations to form different polygonal hollow column shapes. The coupling notches 22 may be angled to form pentagonal section hollow columns when five crib elements are assembled with appropriate angular connections. The pentagonal configuration may provide an alternative column geometry that may be suitable for specific mine tunnel applications or loading conditions.

[0100] The coupling notches 22 may be configured to form triangular section hollow columns when three crib elements are assembled together. The triangular configuration may provide a compact column geometry that may be suitable for applications where space constraints limit the available footprint for support structures. The triangular hollow column may maintain structural integrity while providing efficient material utilisation. In some configurations, the coupling notches 22 may be angled to form heptagonal section hollow columns when seven crib elements are assembled together. The heptagonal configuration may provide increased perimeter contact area compared to hexagonal configurations while maintaining the hollow interior space that reduces overall material requirements.

[0101] The coupling mechanism may enable formation of octagonal section hollow columns when eight crib elements are assembled with appropriate angular connections. The octagonal configuration may approach circular geometry while maintaining the discrete coupling interfaces provided by the coupling notches 22. The octagonal hollow column may provide enhanced load distribution characteristics due to the increased number of structural elements in the assembly.

[0102] The coupling notches 22 may be configured to form nonagonal section hollow columns when nine crib elements are assembled together. The nonagonal configuration may provide further approximation to circular geometry while maintaining the modular assembly characteristics of the discrete crib elements. The increased number of elements in the nonagonal configuration may provide enhanced structural redundancy in the assembled column.

[0103] In some cases, the coupling notches 22 may be angled to form decagonal section hollow columns when ten crib elements are assembled together. The decagonal configuration may closely approximate circular geometry while maintaining the benefits of modular assembly and standardised component manufacturing. The decagonal hollow column may provide smooth load distribution characteristics that approach those of circular support structures.

[0104] The coupling mechanism may enable formation of circular section hollow columns through appropriate angular configuration of the coupling notches 22. The circular configuration may be achieved through precise angular control of the coupling interfaces or through the use of a large number of crib elements assembled with small angular increments between adjacent elements. The circular hollow column may provide optimal load distribution characteristics while maintaining the hollow interior space that reduces material usage.

[0105] Referring to Figure 6, a hollow column may be formed by a stack of coupled crib elements that provide structural support for mine tunnel roof applications. The hollow column may include multiple crib elements 10 stacked and coupled together to form the column structure. The crib elements 10 may be arranged in a configuration that creates a hollow interior space while providing the structural integrity needed for roof support applications. The assembly may include a first crib element 10 shown separately beside the stack, featuring coupling notches 22 at both the top face 19 and the bottom face 18 of each end. The coupling notches 22 may provide connection interfaces that enable adjacent crib elements to engage at predetermined angles. The notch walls 222 may be configured to guide the coupling between adjacent crib elements and may define the angular relationship between connected elements.

[0106] The internal wall 11 of the crib elements 10 may form part of the inner surface of the hollow column when multiple elements are assembled together. The internal wall 11 may contribute to the structural boundary of the hollow interior space while providing load-bearing capacity for the assembled column structure.

[0107] As shown in Figure 6, the assembly may include a half crib element 210 that has been cut from a full crib element 10. It may also be formed in that way - as a half height crib element 210.

[0108] The half crib element 210 may be used to provide a flush surface at the top of the column assembly. The half crib element 210 may have a reduced height compared to the full crib elements 10. It may be configured to fit between other crib elements in the assembly to create a level upper surface.

[0109] The crib element 210 flush surface is a base plate to close the voids at the base.

[0110] The assembly process may involve alternating the first crib elements 10 and half crib elements 210 to form a base ring configuration. The alternating arrangement may enable proper angular alignment between adjacent elements while creating the polygonal perimeter needed for the hollow column structure. The coupling notches 22 on the top face 19 and bottom face 18 may facilitate the coupling between stacked elements by providing engagement surfaces that distribute loads across the contact interfaces.

[0111] The stacking arrangement may continue with additional crib elements 10 placed on top of the base ring until the column reaches the desired height for roof contact. The coupling notches 22 may enable each layer of crib elements to engage with the layer below while maintaining the hollow column geometry throughout the vertical extent of the structure.

[0112] The half crib element 210 may be positioned in the final assembly to provide a flush and flat top surface where all the crib elements are level with one another. The half crib element 210 may fill gaps in the top row of the full crib elements 10 to create a uniform upper surface that can distribute roof loads evenly across the assembled column structure. The hollow hexagonal crib column may require six crib components per assembly. The six components may be formed from three double-sided parts that are cut down along the midline plate 60. The cutting operation may divide each full -height crib element 10 along the longitudinal plane 66 to create the half crib elements 210 needed for the assembly configuration.

[0113] The modular design approach may enable the entire crib column assembly to be formed from a single component design. The inventory may be reduced to one single component part through the use of symmetrical crib elements 10 that can be cut along the midline plate 60 to create the half crib elements 210 needed for flush top surface configuration. The standardised component approach may simplify manufacturing, inventory management, and field assembly operations while providing consistent structural properties throughout the assembled column structure.

[0114] Referring to Figure 7, a hexagonal crib column 50 may be formed through assembly of multiple crib elements 10 arranged in a polygonal configuration. The hexagonal crib column 50 may provide structural support for mine tunnel roof applications while creating a hollow interior space that reduces material usage compared to solid support structures. The hexagonal geometry may offer structural stability through the distribution of loads across six discrete crib elements 10 that form the perimeter of the column.

[0115] The hexagonal crib column 50 may include a hexagonal perimeter 110 that defines the outer boundary of the assembled structure. The hexagonal perimeter 110 may be formed by the coupling of six crib elements 10 through their respective coupling notches 22 at predetermined angular relationships. Each crib element 10 may connect to adjacent crib elements at approximately 120-degree angles to create the hexagonal geometry of the assembled column.

[0116] As shown in Figure 7, each crib element 10 may include radiused ends 27 positioned at the terminal portions of the elongate body 12. The radiused ends 27 may reduce stress concentrations that could otherwise occur at sharp corners during loading conditions. The radiused ends 27 may provide smooth transitions between adjacent crib elements 10 in the assembled hexagonal perimeter 110, contributing to improved load distribution characteristics throughout the column structure.

[0117] The hexagonal perimeter 110 may provide a balance between structural efficiency and material utilisation. The six-sided configuration may offer greater load-bearing capacity compared to triangular configurations while using fewer components than octagonal or higher-order polygonal arrangements. The hexagonal geometry may distribute roof loads across the six crib elements 10 while maintaining the hollow interior space that reduces the overall weight of the support structure.

[0118] With continued reference to Figure 7, the positioning of the coupling notches 22 on each crib element 10 may influence the overall dimensions and structural characteristics of the hexagonal crib column 50. The coupling notches 22 may be positioned at specific distances from the first end 14 and second end 15 of each elongate body 12 to achieve desired column properties and load distribution characteristics.

[0119] Referring to Figure 8, an alternative configuration of the hexagonal perimeter 110 may be achieved through different positioning of the coupling notches 22 on the crib elements 10. The coupling notches 22 may be disposed further toward each end of the crib elements 10 compared to the configuration shown in Figure 7. This alternative positioning may provide a wider footprint for the hollow column relative to the same size of crib element 10.

[0120] The wider footprint configuration shown in Figure 8 may offer increased stability characteristics due to the expanded base dimensions of the hexagonal perimeter 110. The increased footprint may provide enhanced resistance to lateral forces and may improve the overall stability of the assembled column structure. The wider configuration may be suitable for applications where increased lateral stability is needed or where the available floor space can accommodate the larger column footprint.

[0121] The positioning of the coupling notches 22 further toward the ends of the crib elements 10 may affect stress distribution within the assembled column structure. The extended coupling arrangement may create increased stresses at the ends of the crib elements 10 under high loading conditions. The stress concentration at the ends may need to be considered in applications where the column will be subjected to high compressive loads or dynamic loading conditions.

[0122] The radiused ends 27 may provide particular benefits in the wider footprint configuration shown in Figure 8. The radiused ends 27 may help to mitigate stress concentrations that could be amplified by the extended coupling arrangement. The smooth transitions provided by the radiused ends 27 may distribute stresses more evenly throughout the connection regions between adjacent crib elements 10.

[0123] The choice between the configurations shown in Figures 7 and 8 may depend on specific application requirements including available space, loading conditions, and stability requirements. The narrower footprint configuration of Figure 7 may be suitable for applications where space is limited or where material efficiency is a primary consideration. The wider footprint configuration of Figure 8 may be preferred for applications where maximum stability is needed or where the loading conditions require enhanced lateral resistance.

[0124] Both configurations may maintain the hollow interior space that provides material savings while preserving the structural integrity needed for mine roof support applications. The hexagonal perimeter 110 in both configurations may provide efficient load distribution while enabling modular assembly from standardised crib elements 10. The flexibility to adjust the column footprint through coupling notch positioning may allow the same basic crib element design to serve multiple application requirements with different dimensional and stability characteristics.

[0125] Referring to Figures 9A-9E, various arrangements of internal void patterns may be implemented within crib elements to achieve different structural and weight characteristics. The internal void patterns may be configured within the perimeter wall 30 to provide mass reduction while maintaining the load-bearing capacity needed for mine roof support applications. Each void pattern configuration may offer distinct advantages in terms of manufacturing feasibility, structural performance, and material efficiency.

[0126] The internal void arrangements shown in Figures 9A-9E may include different geometric patterns that distribute throughout the interior of the crib elements. The void patterns may be designed to optimise the balance between weight reduction and structural integrity while accommodating various manufacturing processes and material flow characteristics during production.

[0127] As shown in Figure 9C, a regular array of honeycomb voids 32 may be arranged within the perimeter wall 30 in a hexagonal pattern configuration. The honeycomb voids 32 may be arranged in a repeating hexagonal pattern that extends across the interior of the crib element between the perimeter walls 30. This honeycomb arrangement may provide an internal structure that reduces mass while maintaining structural integrity through efficient load distribution characteristics.

[0128] The hexagonal honeycomb pattern shown in Figure 9C may offer advantages in terms of structural efficiency and manufacturing consistency. The hexagonal geometry may provide optimal space utilisation while distributing loads evenly throughout the crib element structure. The regular hexagonal pattern may facilitate consistent material flow during moulding processes and may provide predictable structural properties throughout the manufactured crib element.

[0129] With continued reference to Figures 9A-9E, alternative void pattern configurations may include circular void arrangements, rectangular void patterns, triangular void geometries, and irregular void distributions. Each pattern configuration may provide different characteristics in terms of structural performance, manufacturing requirements, and material usage efficiency.

[0130] The circular void pattern may provide smooth stress distribution characteristics due to the absence of sharp corners within the void geometry. The circular voids may reduce stress concentrations that could otherwise occur at angular transitions within the internal structure. The circular pattern may be suitable for applications where uniform stress distribution is a primary consideration.

[0131] The rectangular void pattern may offer manufacturing advantages through simplified tooling requirements and straightforward material flow characteristics during production processes. The rectangular geometry may provide efficient space utilisation while enabling consistent wall thickness throughout the crib element structure. The rectangular pattern may be suitable for applications where manufacturing simplicity and cost efficiency are important considerations.

[0132] The triangular void pattern may provide enhanced structural rigidity through the angular geometry of the void boundaries. The triangular configuration may create structural elements within the crib element that resist deformation under loading conditions. The triangular pattern may be suitable for applications where maximum structural rigidity is needed while maintaining weight reduction benefits.

[0133] Based on testing and modelling under stress conditions, the regular array of honeycomb voids 32 shown in Figure 9C may represent the preferred configuration for optimal strength-to- weight ratio characteristics. The hexagonal honeycomb pattern may provide superior structural performance compared to other void arrangements while maintaining efficient material utilisation and manufacturing feasibility.

[0134] The honeycomb void pattern of Figure 9C may offer advantages in load distribution through the interconnected hexagonal geometry that creates a network of structural elements throughout the crib element interior. The hexagonal pattern may provide isotropic strength characteristics that distribute loads uniformly in multiple directions. The honeycomb configuration may resist both compressive and shear forces while maintaining the lightweight characteristics needed for field handling and transportation.

[0135] The preferred honeycomb arrangement may provide manufacturing benefits through consistent material flow characteristics during moulding or additive manufacturing processes. The regular hexagonal pattern may enable uniform cooling and solidification during production, reducing the potential for internal stresses or dimensional variations in the finished crib elements. The honeycomb pattern may also facilitate quality control and inspection processes through the predictable and repeatable internal geometry.

[0136] The structural efficiency of the honeycomb void pattern may result from the natural strength characteristics of hexagonal geometry, which may provide maximum structural capacity with minimum material usage. The hexagonal pattern may distribute loads through the interconnected cell walls while maintaining open void spaces that reduce overall mass. The honeycomb configuration may offer the optimal balance between structural performance and weight reduction for mine roof support applications.

[0137] Referring to Figure 10, a triangular column 300 may be formed through assembly of three crib elements arranged in a triangular configuration. The triangular column 300 may provide an alternative polygonal geometry for mine tunnel roof support applications where space constraints or specific loading conditions may favour a three-sided column structure. The triangular configuration may offer a compact footprint while maintaining the hollow interior space that reduces material usage compared to solid support structures.

[0138] The triangular column 300 may be assembled through the use of crib elements that incorporate angled coupling mechanisms configured for three-element assembly. A coupling notch 350 may be visible at one of the joints where the crib elements meet to form the triangular configuration. The coupling notch 350 may be angled to enable connection between adjacent crib elements at approximately 120-degree angles, which may be the same angular configuration used for hexagonal assemblies but applied to a three-element arrangement.

[0139] The coupling notch 350 may demonstrate the adaptability of the angled coupling mechanism for different column geometries beyond hexagonal configurations. The same basic coupling notch design that enables hexagonal column formation may be utilised to create triangular columns through the assembly of three crib elements rather than six. This flexibility may provide inventory management benefits by allowing a single crib element design to serve multiple column geometry requirements. The triangular column 300 may offer structural advantages in applications where lateral forces are primarily unidirectional or where the available installation space is limited. The three-sided configuration may provide efficient load distribution while requiring fewer individual crib elements compared to hexagonal or higher-order polygonal arrangements. The reduced component count may simplify field assembly operations while maintaining the structural integrity needed for roof support applications.

[0140] With continued reference to Figure 10, the triangular column 300 may maintain the hollow interior space that characterises the polygonal column configurations. The hollow interior may reduce the overall weight of the support structure while preserving the load-bearing capacity provided by the three crib elements that form the perimeter of the triangular column 300. The hollow configuration may also provide material savings compared to solid triangular support structures.

[0141] The angled coupling mechanism that enables formation of the triangular column 300 may be adapted for various other polygonal column shapes through appropriate angular configuration of the coupling notches. The coupling notches may be angled to accommodate different numbers of crib elements in the assembly, with the angular relationship between adjacent elements determined by the desired final column geometry.

[0142] For pentagonal column configurations, the coupling notches may be angled to enable connection between adjacent crib elements at angles that facilitate five-element assembly. The pentagonal configuration may provide increased perimeter contact area compared to triangular arrangements while using fewer components than hexagonal configurations. The five-sided geometry may offer a balance between structural capacity and component efficiency for specific application requirements.

[0143] The coupling mechanism may enable formation of heptagonal column configurations through appropriate angular adjustment of the coupling notches. The seven-element assembly may provide increased structural redundancy compared to hexagonal configurations while maintaining the modular assembly characteristics of the discrete crib elements. The heptagonal geometry may approach circular load distribution characteristics while preserving the benefits of standardised component manufacturing.

[0144] The adaptability of the angled coupling mechanism may extend to higher-order polygonal configurations including octagonal, nonagonal, and decagonal column arrangements. Each configuration may provide different structural characteristics and footprint dimensions while utilising the same basic crib element design with appropriately angled coupling notches. The flexibility to create multiple column geometries from a single component design may provide significant advantages in inventory management and manufacturing efficiency.

[0145] The triangular column 300 configuration may demonstrate the scalability of the coupling mechanism across different polygonal arrangements. The same principles that enable three- element triangular assembly may be extended to any number of crib elements through appropriate angular configuration of the coupling notches. This scalability may allow the column geometry to be optimised for specific application requirements while maintaining the benefits of modular assembly and standardised component production.

[0146] The crib elements may be formed from various polymer materials that provide advantages over traditional timber construction for mine tunnel roof support applications. The polymer materials may offer consistent material properties, dimensional stability, and resistance to environmental degradation that can affect wooden crib systems in underground mining environments.

[0147] The elongate body may be formed from a polymer selected from various engineering polymer families. The polymer selection may include polypropylene in all grades including co-polymer, random co-polymer, and homopolymer formulations. Polypropylene may provide chemical resistance, dimensional stability, and consistent mechanical properties that make the material suitable for underground mining applications where environmental conditions can vary significantly.

[0148] The polymer material may include polyethylene or other materials in the polyolefin family. Polyethylene may offer impact resistance, chemical inertness, and processing advantages that facilitate manufacturing of crib elements with consistent dimensional accuracy. The polyolefin family of materials may provide a range of mechanical properties that can be tailored to specific application requirements through material selection and processing parameters.

[0149] The elongate body may be formed from acetal polymers that provide high strength, stiffness, and dimensional stability characteristics. Acetal materials may offer resistance to creep deformation under sustained loading conditions, which may be beneficial for mine roof support applications where crib elements experience continuous compressive loads over extended periods.

[0150] Polycarbonate materials may be used to form the elongate body where high impact strength and temperature resistance are needed. Polycarbonate may provide transparency characteristics that could facilitate visual inspection of crib element condition during service, though this property may not be necessary for typical underground mining applications.

[0151] The polymer material may include ABS (acrylonitrile butadiene styrene) formulations that provide a balance of strength, toughness, and processability. ABS materials may offer good impact resistance and dimensional stability while maintaining ease of manufacturing through conventional moulding processes.

[0152] PPS (polyphenylene sulfide) may be used where enhanced chemical resistance and high temperature performance are required. PPS materials may provide superior resistance to chemical degradation in harsh underground environments while maintaining mechanical properties over extended service periods.

[0153] TPU (thermoplastic polyurethane) materials may be selected where flexibility and impact absorption characteristics are beneficial. TPU may provide energy absorption capabilities that could help mitigate dynamic loading conditions that may occur during mining operations.

[0154] PEEK (polyetheretherketone) may be used in applications requiring maximum chemical resistance and mechanical property retention under extreme conditions. PEEK materials may provide the highest performance characteristics among the polymer options, though the material cost may limit application to specialised requirements.

[0155] Acrylic polymers may be selected where optical clarity, weather resistance, or specific chemical compatibility requirements exist. Acrylic materials may provide good dimensional stability and processing characteristics while offering resistance to environmental degradation.

[0156] The polymer material may comprise composite formulations that incorporate various additives to enhance specific properties. The polymer composite may include short or long additive filled engineering polymers that provide reinforcement and property modification compared to unfilled polymer materials. The additive content may be tailored to achieve desired mechanical properties, processing characteristics, and cost targets for specific applications.

[0157] Glass filled polymers may be used to increase the strength and stiffness of the crib elements while maintaining relatively low density compared to metal alternatives. Glass fibre reinforcement may provide enhanced load-bearing capacity and reduced creep deformation under sustained loading conditions. The glass fibre content may be varied to optimise the balance between mechanical properties and processing characteristics during manufacturing. Mineral filled polymers may incorporate various mineral additives that provide cost reduction, dimensional stability, and specific property enhancements. Mineral fillers may include materials such as calcium carbonate, silica, or clay that modify the polymer properties while reducing material costs compared to unfilled polymers.

[0158] Calcium or talc filled polymers may provide enhanced stiffness and dimensional stability while reducing material costs and improving processing characteristics. Calcium carbonate fillers may offer good dispersion characteristics and neutral chemical properties that do not interfere with polymer performance. Talc fillers may provide enhanced stiffness and heat deflection temperature while maintaining good surface finish characteristics in moulded parts.

[0159] The polymer material may contain suitable additional additives that provide specific performance enhancements or processing benefits. Additional additives may include stabilisers, colourants, processing aids, or speciality modifiers that optimise the material properties for mine tunnel roof support applications.

[0160] In some configurations, the elongate body may be formed from metal materials that provide alternative performance characteristics compared to polymer construction. Metal materials may offer enhanced strength and stiffness properties while maintaining dimensional stability under high loading conditions. The metal construction may be suitable for applications where maximum load-bearing capacity is required or where environmental conditions exceed the capabilities of polymer materials.

[0161] The polymer construction may provide significant advantages over traditional timber materials used in conventional crib systems. Polymer materials may offer consistent material properties that do not vary with moisture content, grain orientation, or natural defects that can affect wooden crib elements. The consistency of polymer materials may enable predictable structural performance and simplified design calculations compared to the variable properties of natural timber.

[0162] Moisture resistance may represent a major advantage of polymer construction over timber materials. Polymer crib elements may not absorb water or experience dimensional changes due to moisture exposure, eliminating the weight increase and potential decay problems associated with wooden cribs in underground mining environments. The moisture resistance may maintain consistent handling characteristics and structural properties throughout the service life of the crib elements. Dimensional stability of polymer materials may provide advantages in maintaining proper fit and engagement between coupled crib elements over time. Polymer materials may not experience the shrinkage, swelling, or warping that can affect timber crib elements due to moisture changes or natural ageing processes. The dimensional stability may ensure consistent assembly characteristics and structural performance throughout the service life of the crib system.

[0163] Weight reduction may be achieved through polymer construction combined with the internal void network design. Polymer materials may provide favourable strength-to-weight ratios compared to timber while enabling the incorporation of internal voids that further reduce mass without compromising structural integrity. The weight reduction may facilitate handling, transportation, and installation operations while reducing the physical demands on mining personnel during crib assembly operations.

[0164] The polymer construction may eliminate variability in material properties that can affect timber crib systems due to differences in wood species, drying conditions, or processing methods. Polymer materials may be manufactured with consistent properties that do not depend on natural growth conditions or processing variables that can affect timber quality. The consistency may enable standardised design approaches and predictable performance characteristics across all crib elements in a given application.

[0165] Referring to Figure 11, a testing arrangement is shown for evaluating the strength characteristics of crib assemblies under axial compression loading conditions. The testing arrangement enabled a systematic assessment of load-bearing capacity and displacement characteristics of hollow crib column assemblies formed from the polymer-based crib elements described herein.

[0166] The testing arrangement was used to assess the strength of the crib and its elements. The rig included a HongShan machine frame that provides structural support for the compression testing apparatus. The machine frame was configured to resist the reaction forces generated during high-load compression testing while maintaining precise alignment of the test specimen throughout the loading sequence. The frame structure provided the rigid foundation needed to ensure accurate load application and measurement during testing operations.

[0167] A cross head was positioned at the top of the machine frame to provide the upper reaction point for the compression testing arrangement. The cross head was fixed in position during testing operations to provide a stable reference point against which compressive loads are applied to the test specimen. The fixed cross head configuration ensured that loading forces were transmitted directly through the test specimen without introducing lateral forces or misalignment that could affect test results.

[0168] The testing arrangement may include a bottom platen assembly positioned at the base of the machine frame. The bottom platen assembly may provide the lower contact surface for the test specimen and may incorporate the loading mechanism used to apply compressive forces during testing. The bottom platen may be configured to move upward during testing operations while the cross head remains fixed, creating the compression loading condition applied to the test specimen.

[0169] A PPC specimen was positioned between the top platen and the bottom platen within the testing arrangement. The PPC specimen represented the hollow crib column assembly formed from multiple crib elements coupled together in the polygonal configuration described herein. The specimen positioning ensured good alignment between the loading surfaces and the crib column assembly to achieve uniform load distribution during compression testing.

[0170] The bottom platen incorporated an actuator mechanism that provides the motive force for applying compressive loads to the test specimen. The actuator was configured to drive the bottom platen upward at controlled rates while maintaining precise positioning throughout the loading sequence. The actuator mechanism enabled both monotonic loading conditions and cyclic loading patterns depending on the specific testing requirements.

[0171] A load cell was integrated into the bottom platen assembly to provide accurate measurement of the applied compressive forces during testing operations. The load cell was configured to measure loads up to the maximum capacity of the testing machine while maintaining accuracy throughout the full range of applied forces. The load cell measurements were recorded at regular intervals during testing to provide detailed load-displacement data for analysis of the crib assembly performance characteristics.

[0172] The testing arrangement included displacement measurement capability through a displacement transducer that monitors the position of the actuator throughout the loading sequence. The displacement transducer provided accurate measurement of the compression displacement experienced by the test specimen as loads are applied. The displacement measurements were synchronised with load cell readings to provide comprehensive loaddisplacement data for characterising the structural response of the crib assembly. The loading direction is indicated by an upward arrow from the bottom of the frame, showing that compressive forces are applied by driving the bottom platen upward against the fixed cross head. This loading configuration may simulate the compression loading conditions that crib columns experience in mine tunnel roof support applications where the column is compressed between the tunnel floor and roof surfaces.

[0173] The testing methodology involved monotonic compression testing where loads are applied continuously until specimen failure occurs. The monotonic loading approach provided data on the ultimate load-bearing capacity of the crib assembly while characterising the loaddisplacement response throughout the loading sequence. The continuous loading simulated extreme loading conditions that could occur during roof settlement or other high-stress mining operations.

[0174] Load and actuator position measurements were recorded at regular intervals during testing operations to provide detailed documentation of the crib assembly response characteristics. The measurement intervals were selected to capture sufficient data points for accurate characterisation of the load-displacement relationship while avoiding excessive data volume that could complicate analysis procedures.

[0175] Referring to Figure 12, a hexagonal crib assembly (HONGSHAN YAJ10000) was positioned within the test rig before loading to evaluate the structural performance characteristics of the assembled column configuration. The crib assembly consisted of stacked polymer crib elements arranged to form a hollow hexagonal column structure. The crib elements were interlocked using notched connections at their ends to create the assembled column configuration shown in the testing apparatus.

[0176] The pre-test configuration shown in Figure 12 demonstrated the assembled hexagonal crib column positioned between the testing plates of the compression testing machine. The crib assembly maintained its intended geometric configuration with good alignment between the individual crib elements that form the hexagonal perimeter.

[0177] The hexagonal crib assembly shown in Figure 12 represented the assembled configuration that would be used in mine tunnel roof support applications. The hollow interior space of the assembled column may be visible, demonstrating the material-efficient design that reduces weight while maintaining structural integrity. The modular assembly of individual crib elements may create the polygonal column structure through the angled coupling mechanisms described herein. Referring to Figure 13, the crib assembly is shown positioned within the testing rig after undergoing load testing to failure.

[0178] The post-failure configuration shown in Figure 13 provided visual documentation of the failure mode experienced by the hexagonal crib assembly under high compressive loading conditions. The top third of the column was buckled outward, bulging. The structural components of the testing apparatus may remain intact around the failed crib assembly, indicating that the testing equipment successfully applied the intended loading forces throughout the test sequence.

[0179] The failure condition shown in Figure 13 demonstrated the ultimate load-bearing capacity of the assembled hexagonal crib column configuration. The post-failure state may provide information about the structural behaviour of the polymer-based crib elements under extreme loading conditions that could occur during severe roof settlement or other high-stress mining operations.

[0180] As shown in Figure 13, the crib assembly was subjected to approximately 10,000 kN of compressive force during the testing sequence. This loading level represents the ultimate capacity of the assembled hexagonal column configuration formed from the polymer-based crib elements. The high load capacity demonstrates the structural effectiveness of the hollow column design and the angled coupling mechanism that connects individual crib elements into the assembled structure.

[0181] Referring to Figure 14, a graph shows the relationship between load and actuator position during testing of the crib assembly. The graph demonstrates the load-displacement response characteristics of the hexagonal crib column throughout the compression testing sequence from initial loading through ultimate failure of the assembled structure.

[0182] The load-displacement relationship shown in Figure 14 exhibits a generally increasing load response from zero to approximately 8,862 kN as the actuator position increases from zero to about 108 mm. The curve demonstrates an initial steep rise in load capacity followed by a more gradual increase as the displacement continues. The load-displacement characteristics may provide information about the elastic response of the crib assembly during initial loading and the progressive deformation behaviour as loads approach the ultimate capacity.

[0183] The graph shown in Figure 14 indicates that the maximum recorded load reached 8,862 kN at a displacement of 108 mm before failure occurred. This maximum load capacity may represent the ultimate compressive strength of the assembled hexagonal crib column configuration under the testing conditions applied. The displacement at maximum load may indicate the deformation characteristics of the assembled structure when subjected to extreme loading conditions.

[0184] With continued reference to Figure 14, the load-displacement curve may show a relatively flat section near the peak load before failure occurs. This plateau region may indicate that the crib assembly maintains load-bearing capacity over a range of displacement values near the ultimate load limit. The plateau characteristics may provide information about the ductile behaviour of the assembled structure and the progressive failure mechanisms that occur as individual crib elements reach their ultimate capacity.

[0185] Other testing results demonstrate that individual crib elements achieve a maximum load of approximately 1,000 kN when compressed individually under compression loading conditions. The individual element testing involved loading single crib elements in various orientations including upright positioning, lying on one side, and end-to-end loading configurations. The displacement at maximum load for individual elements ranged between 5 mm and 10 mm before the testing machine (the INSTRON 8036) reached its capacity limit.

[0186] The performance data for individual crib elements provides baseline information for understanding the contribution of each element to the overall capacity of the assembled column structure. The individual element capacity of approximately 1,000 kN may be compared to the assembled column capacity of 8,862 kN to evaluate the effectiveness of the coupling mechanism and the structural benefits achieved through the hollow column configuration.

[0187] The assembled crib column may demonstrate significantly higher load-bearing capacity compared to individual elements due to the structural advantages of the hollow column geometry and the load distribution characteristics of the hexagonal configuration. The assembled column capacity of 8,862 kN may represent approximately 8.9 times the capacity of individual elements, indicating effective load sharing and structural efficiency in the assembled configuration.

[0188] The displacement characteristics may differ between individual elements and assembled columns, with individual elements showing failure at 5-10 mm displacement while the assembled column accommodates 108 mm displacement at maximum load. The increased displacement capacity of the assembled column may indicate enhanced ductility and energy absorption characteristics compared to individual element behaviour.

[0189] The testing results may provide validation of the structural design approach and demonstrate the effectiveness of the polymer-based crib elements for mine tunnel roof support applications. The high load capacity and controlled failure characteristics may indicate that the assembled crib columns can provide reliable structural support while offering predictable performance characteristics under extreme loading conditions.

[0190] Referring to Figure 15, a packer 500 may be provided as an accessory component for the crib system to enable fine height adjustments during column assembly and roof contact optimisation. The packer may be formed using similar polymer construction and internal void design principles as the crib elements described herein. The packer may include an elongate body with a honeycomb internal structure that extends across the width of the component between outer walls, providing mass reduction while maintaining structural integrity.

[0191] The packer shown in Figure 15 may incorporate the same polymer materials used in the crib elements, including polypropylene, polyethylene, or other engineering polymers that provide consistent material properties and environmental resistance. The polymer construction may offer advantages over traditional wooden packing materials through dimensional stability, moisture resistance, and predictable structural characteristics that do not vary with environmental conditions.

[0192] The internal structure of the packer may comprise a regular array of honeycomb voids arranged in a hexagonal pattern similar to that used in the crib elements. The honeycomb structure may extend across the interior of the packer between the outer walls, creating a lightweight design that reduces handling weight while preserving the load-bearing capacity needed for roof support applications. The honeycomb voids may be closed by upper and lower surfaces that provide contact interfaces for load distribution.

[0193] As shown in Figure 15, the packer may include coupling features that enable integration with the crib column assembly. The coupling features may comprise notched connections positioned at the ends of the packer to facilitate attachment to crib elements or other system components. The coupling mechanism may enable the packer to be inserted into the crib column assembly at locations where height adjustments are needed to achieve proper roof contact.

[0194] The packer may be dimensioned to provide incremental height adjustments that accommodate variations in tunnel height or minor dimensional differences in assembled crib columns. The height of the packer may be selected to provide fine-tuning capability that enables precise adjustment of the total column height to achieve optimal contact with roof surfaces. The packer dimensions may be standardised to provide consistent adjustment increments while maintaining compatibility with the modular crib element system. With continued reference to Figure 15, the packer may be manufactured using the same moulding or additive manufacturing processes used for the crib elements. The manufacturing consistency may ensure that packers maintain the same dimensional accuracy and material properties as the primary crib components. The standardised manufacturing approach may provide cost efficiency and quality consistency across all components in the crib system.

[0195] Referring to Figure 16, a wedge component 600 may be provided as an additional accessory for the crib system to enable angle adjustments and enhanced load distribution characteristics. The wedge may be formed using similar polymer construction and internal void design principles as the crib elements and packers described herein. The wedge may provide angular adjustment capability that enables optimisation of contact angles between crib columns and roof surfaces that may not be perfectly horizontal.

[0196] The wedge shown in Figure 16 may include a tapered configuration that provides angular adjustment capability when positioned between crib column assemblies and roof surfaces. The tapered geometry may enable compensation for roof slopes or irregular surface conditions that could otherwise result in point loading or uneven load distribution across the column assembly. The wedge may distribute loads more evenly across the contact interface while accommodating angular variations in roof geometry.

[0197] The internal structure of the wedge may incorporate the same honeycomb void pattern used in the crib elements and packers. The honeycomb voids may be arranged in a regular hexagonal pattern that extends throughout the interior of the wedge component. The internal void structure may provide weight reduction benefits while maintaining the structural integrity needed to transmit loads between the crib column and roof surfaces under various angular orientations.

[0198] The polymer construction of the wedge may provide the same material advantages as the crib elements, including dimensional stability, moisture resistance, and consistent mechanical properties. The polymer materials may maintain their structural characteristics under the loading conditions experienced in mine tunnel applications while providing resistance to environmental degradation that could affect traditional wooden wedging materials.

[0199] As shown in Figure 16, the wedge may be configured with surface features that enhance contact characteristics with both crib column assemblies and roof surfaces. The contact surfaces may be designed to provide stable engagement that prevents slippage or displacement during loading conditions. The surface configuration may distribute contact pressures evenly to avoid stress concentrations that could lead to localised failure or deformation. The wedge component may be manufactured using the same production processes as the crib elements and packers, ensuring consistency in material properties and dimensional accuracy across all system components. The standardised manufacturing approach may provide cost efficiency while maintaining the quality standards needed for reliable performance in mine tunnel roof support applications.

[0200] The combination of packers and wedges may provide comprehensive adjustment capability that enables optimisation of crib column installations for various tunnel geometries and roof conditions. The packers may address height variations while the wedges accommodate angular adjustments, together providing the fine-tuning capability needed to achieve optimal load distribution and structural performance in field installations.

[0201] The accessory components may be designed to integrate seamlessly with the modular crib element system while providing the flexibility needed to accommodate real-world installation conditions. The polymer construction and honeycomb void design may ensure that packers and wedges maintain the same performance characteristics and environmental resistance as the primary crib components throughout their service life.

[0202] The manufacturing method for producing crib components may involve various polymer processing techniques that enable formation of complex internal geometries while maintaining dimensional accuracy and consistent material properties. The manufacturing approach may provide advantages in terms of production efficiency, component standardisation, and inventory management through the use of a single component design that serves multiple assembly functions.

[0203] A method of forming a crib component for assembly into a hollow crib column may comprise forming a first elongate crib element from a moulding or additive process. The moulding process may include injection moulding techniques that enable formation of complex internal void structures while maintaining precise dimensional control over external surfaces and coupling features. Injection moulding may provide advantages in terms of production speed, material efficiency, and surface finish quality for polymer-based crib components.

[0204] The injection moulding process may involve injecting molten polymer material into a mould cavity that defines both the external geometry and internal void structure of the crib element. The mould design may incorporate core structures that create the internal honeycomb void pattern while maintaining material flow characteristics that ensure complete filling of all mould sections. The moulding process may enable formation of complex internal geometries that would be difficult or impossible to achieve through conventional machining or assembly operations.

[0205] Additive manufacturing processes may provide alternative production methods for forming crib components with internal void structures. The additive process may comprise 3D printing techniques that build the crib element layer by layer, enabling formation of internal honeycomb patterns without the need for complex mould tooling. 3D printing may offer advantages in terms of design flexibility, rapid prototyping capability, and the ability to produce small quantities of specialised components without significant tooling investments.

[0206] The first elongate crib element formed through the moulding or additive process may include a polymer material with a plurality of internal voids for reducing mass. The internal voids may be formed simultaneously with the external geometry during the manufacturing process, creating an integrated structure that combines lightweight characteristics with structural integrity. The polymer material may be selected from the group consisting of polypropylene, polyethylene, acetal, polycarbonate, ABS, PPS, TPU, PEEK, and acrylic, depending on the specific performance requirements and processing characteristics needed for the application.

[0207] The manufacturing process may form coupling notches angled at other than perpendicular and disposed at each end and on top and bottom faces of the elongate crib element. The angled coupling notches may be formed as integral features during the moulding or additive manufacturing process, eliminating the need for secondary machining operations. The coupling notches may be configured to connect the first elongate crib element to like elongate crib elements at an angle of approximately 120 degrees to facilitate formation of a hexagonal hollow crib column.

[0208] The first elongate crib element may further comprise an internal plate disposed at a midway point between the top and bottom faces. The internal plate may be formed as an integral feature during the manufacturing process, creating a structural element that divides the internal void structure into upper and lower sections. The internal plate may provide reinforcement across the width of the crib element while creating a defined cutting plane for subsequent processing operations.

[0209] The plurality of internal voids may comprise a regular array of honeycomb voids extending from the top face to the internal plate and from the bottom face to the internal plate. The honeycomb void structure may be formed during the manufacturing process through appropriate mould design or additive manufacturing programming that creates the hexagonal void pattern throughout the interior of the crib element. The honeycomb voids may terminate at the internal plate, creating separate upper and lower void regions within the manufactured component.

[0210] The method may further include cutting the first crib element along the midway point between top and bottom faces to provide a second half-component which can fit between other first full crib elements for providing a flush and flat upper crib columnar roof surface. The cutting operation may be performed after the manufacturing process is complete, dividing the fullheight crib element into two half-height components through a single cutting operation along the internal plate.

[0211] The cutting procedure may provide a closed surface on the second half-component due to the presence of the internal plate at the midway point. The internal plate may serve as a cutting guide that ensures accurate division of the crib element while providing a finished surface on the resulting half-component. The closed surface created by the internal plate may eliminate the need for additional finishing operations on the cut surface, providing a ready-to-use component with appropriate surface characteristics for load distribution.

[0212] The cutting operation may be performed using various techniques including sawing, laser cutting, or water jet cutting depending on the polymer material and dimensional accuracy requirements. The cutting process may be designed to minimise material waste while providing clean, accurate cuts along the internal plate. The cutting operation may be performed in a controlled manufacturing environment to ensure consistent dimensional accuracy across all half-components produced from full-height crib elements.

[0213] The component rationalisation approach may enable inventory management benefits through the production of multiple component types from a single manufactured element. The manufacturing process may produce full-height crib elements that can be used directly in column assemblies or cut to produce half-height components as needed. This approach may reduce inventory complexity by eliminating the need to manufacture and stock separate component types for different assembly functions.

[0214] The single component design may provide manufacturing efficiency through standardised production processes, tooling, and quality control procedures. The manufacturing setup may be optimised for production of the full-height crib element, with cutting operations performed as needed to produce half-components. This approach may reduce manufacturing complexity while providing flexibility to adjust the ratio of full -height to half-height components based on assembly requirements.

[0215] The inventory rationalisation may provide cost benefits through reduced tooling requirements, simplified production planning, and decreased storage complexity. The single component approach may eliminate the need for separate moulds or manufacturing setups for different component types while providing the flexibility to produce the mix of full and half components needed for various assembly configurations.

[0216] The manufacturing method may enable consistent material properties and dimensional accuracy across all components produced from the same base design. The full-height and halfheight components may maintain identical material characteristics, surface finish, and dimensional tolerances due to their common manufacturing origin. This consistency may ensure predictable assembly characteristics and structural performance regardless of the specific combination of full and half components used in a given crib column assembly.

[0217] The polymer processing parameters may be optimised to ensure complete formation of the internal void structure while maintaining structural integrity of the thin walls that separate adjacent voids. The processing conditions may be controlled to achieve proper material flow, cooling characteristics, and dimensional stability throughout the complex internal geometry of the manufactured crib element.

[0218] Quality control procedures may be implemented during the manufacturing process to ensure consistent formation of the internal void structure, accurate dimensions of the coupling notches, and proper positioning of the internal plate. The quality control measures may include dimensional inspection, material property testing, and structural integrity verification to ensure that manufactured components meet the performance requirements for mine tunnel roof support applications.

[0219] The assembly process for constructing a hollow crib column from individual crib elements may involve a systematic sequence of operations that creates a stable polygonal support structure suitable for mine tunnel roof applications. The assembly methodology may enable field personnel to construct support columns without specialised tools or fasteners while achieving consistent structural performance across multiple installations.

[0220] The initial assembly step may involve taking a first elongate crib element and engaging one of the coupling notches at an end with a corresponding coupling notch of a half crib element. The coupling engagement may be achieved by inserting the angled notch of one element into the cooperating angled notch of the adjacent element, creating a mechanical connection that maintains the predetermined angular relationship between the coupled components. The angled geometry of the coupling notches may guide the elements into proper alignment while preventing incorrect assembly orientations.

[0221] The base ring formation may proceed through alternating placement of first crib elements and half crib elements around the intended column perimeter. The alternating arrangement may ensure proper angular spacing between adjacent elements while creating the polygonal geometry needed for the hollow column structure. Each coupling connection may engage at the predetermined angle that corresponds to the desired column cross-section, such as 120 degrees for hexagonal configurations or other angles for alternative polygonal shapes.

[0222] The alternating sequence may continue until the complete base ring is formed with all coupling connections properly engaged. The base ring may establish the foundation geometry for the entire column assembly while providing a stable platform for subsequent stacking operations. The half crib elements in the base ring may be oriented with their flat surfaces facing upward to provide level contact surfaces for the next layer of components.

[0223] Subsequent assembly layers may be constructed by stacking full-height crib elements on top of the base ring configuration. The stacking process may involve placing each full-height element so that its bottom coupling notches engage with the top coupling notches of the elements in the layer below. The vertical stacking may maintain the polygonal column geometry established by the base ring while building the column height toward the intended roof contact elevation.

[0224] The stacking sequence may continue with additional layers of full-height crib elements until the assembled column approaches the required height for roof contact. Each stacked layer may maintain proper angular alignment with the layers below through the engagement of the angled coupling notches. The hollow interior space may be preserved throughout the stacking process, creating the material -efficient column structure that reduces weight while maintaining loadbearing capacity.

[0225] The final assembly step may involve placement of half crib elements in the uppermost layer to create a flush and flat top surface for roof contact. The half crib elements may be positioned in the gaps between the full-height elements in the top layer, with their flat surfaces oriented upward to provide uniform contact with the tunnel roof. This arrangement may ensure that roof loads are distributed evenly across all elements in the top layer rather than being concentrated on individual components.

[0226] The completed assembly may present a uniform upper surface where all crib elements are level with one another, eliminating point loading conditions that could cause localised stress concentrations or uneven load distribution. The flush top surface may maximise the contact area between the column assembly and the roof surface, improving load transfer characteristics and reducing contact pressures that could cause roof damage or column settlement.

[0227] The operational function of the assembled hollow crib column may involve distributing roof loads through the polygonal perimeter structure formed by the coupled crib elements. The load distribution mechanism may transfer compressive forces from the roof contact surface through the individual crib elements that form the column perimeter. Each element in the assembly may contribute to the overall load-bearing capacity while the hollow interior space reduces the total material requirements compared to solid column configurations.

[0228] The perimeter wall structure formed by the assembled crib elements may provide the primary load-bearing mechanism for the column assembly. The perimeter walls may distribute roof loads circumferentially around the column cross-section while the internal honeycomb void structure within each element maintains structural integrity under compressive loading conditions. The combination of perimeter load distribution and internal structural efficiency may enable the hollow column to support substantial roof loads while maintaining relatively low weight characteristics.

[0229] The angled coupling configuration may enhance structural stability through the creation of mechanical interlocks that resist lateral displacement of individual elements within the assembly. The angled coupling notches may prevent relative movement between adjacent elements under lateral loading conditions that could occur due to roof settlement, ground movement, or dynamic forces from mining operations. The mechanical interlock may maintain column geometry and structural integrity even when subjected to combined vertical and lateral loading conditions.

[0230] The polygonal geometry created by the angled coupling arrangement may provide enhanced resistance to lateral forces compared to circular or other column configurations. The flat faces of the polygonal perimeter may distribute lateral loads across multiple contact points while the angular transitions between faces may provide directional stability that resists column rotation or lateral displacement. The polygonal configuration may offer superior stability characteristics in underground environments where lateral forces may be unpredictable in magnitude and direction.

[0231] The hollow interior space of the assembled column may contribute to structural efficiency by reducing the overall weight of the support system while preserving load-bearing capacity. The weight reduction may facilitate handling and installation operations while reducing the foundation loads transmitted to tunnel floors. The hollow configuration may also provide access for visual inspection of column condition and may accommodate utility routing or other operational requirements in some mining applications.

[0232] The modular assembly approach may enable rapid deployment of support columns in underground mining environments where time constraints and working space limitations may affect installation operations. The standardised coupling mechanism may allow assembly teams to construct columns quickly without specialised training or complex procedures. The consistent assembly process may reduce installation time while ensuring reliable structural performance across multiple column installations.

[0233] The load transfer mechanism within the assembled column may involve distribution of roof loads through the coupled interfaces between adjacent crib elements. The angled coupling notches may transfer loads between elements while maintaining structural continuity around the column perimeter. The load transfer capability may enable the column assembly to function as an integrated structural system rather than a collection of individual elements, providing enhanced load-bearing capacity compared to uncoupled element arrangements.

[0234] The structural redundancy inherent in the multi-element assembly may provide enhanced reliability compared to single-component support systems. The failure of individual elements within the assembly may not result in catastrophic column failure due to the load-sharing characteristics of the coupled configuration. The remaining elements may continue to provide structural support while damaged components are identified and replaced, enabling continued operation during maintenance activities.

[0235] The environmental resistance characteristics of the polymer-based crib elements may contribute to long-term operational reliability in underground mining environments. The assembled column may maintain structural properties and dimensional stability despite exposure to moisture, temperature variations, and chemical conditions that could degrade traditional timber support systems. The consistent material properties may ensure predictable structural performance throughout the service life of the installation. The assembly methodology may accommodate various column heights through adjustment of the number of stacked layers while maintaining the same basic assembly procedures. The modular approach may enable optimisation of column height for specific tunnel geometries without requiring different component types or specialised assembly techniques. The height adjustment capability may provide flexibility to address varying roof elevations or settlement conditions that may occur during mining operations.

[0236] A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. Accordingly, other implementations are within the scope of the following claims.

Claims

CLAIMS1. A crib element for assembly into a crib column for supporting a mine tunnel roof, the crib element comprising: an elongate body configured to stack on and couple to other like elongate bodies to form a perimeter of a hollow column; and one or more coupling elements disposed at an end of the elongate body to couple with a cooperating coupling element on a like elongate body, wherein the coupling element is configured to connect its elongate body to another like elongate body at an angle other than perpendicular.

2. The crib element of claim 1, wherein the coupling element comprises a notch for receiving a portion of the like elongate body to couple it to form a peripheral arc of the hollow column.

3. The crib element of claim 2, wherein there are two notches at each end of the elongate body.

4. The crib element of claim 3, wherein the notches at each end are formed on opposing sides of the elongate body.

5. The crib element of any one of claims 1 to 4, wherein the elongate body is formed from a polymer.

6. The crib element of claim 5, wherein the polymer is selected from the group consisting of polypropylene, polyethylene, acetal, polycarbonate, ABS, PPS, TPU, PEEK, and acrylic.

7. The crib element of any one of claims 1 to 6, further comprising a network of internal voids for reducing mass of the elongate body.

8. The crib element of claim 7, wherein the internal voids comprise a regular array of honeycomb voids from one wall of the elongate body to another wall.

9. The crib element of claim 8, further comprising an internal plate disposed midway between a top face and a bottom face of the elongate body, wherein the internal plate closes the honeycomb voids at a midline of the elongate body.

10. The crib element of any one of claims 1-9, wherein the coupling element is configured to connect the elongate body to the like elongate body at an angle of approximately 120 degrees to facilitate formation of a hexagonal hollow column.

11. The crib element of any one of claims 1 to 10 further including one or more radiused ends.

12. The crib element of any one of claims 1 to 11 including a base plate to close the voids at the base.

13. A crib element for assembly into a crib column for supporting a mine tunnel roof, the crib element comprising: an elongate body configured to stack on and couple to other like elongate bodies to form a perimeter of a hollow column; one or more coupling elements disposed at an end of the elongate body to couple with a cooperating coupling element on a like elongate body; and a polymer material including a plurality of internal voids for reducing mass of the elongate body.

14. The crib element of claim 13, wherein the polymer material is formed by a moulding or additive manufacturing process.

15. The crib element of claim 13 or 14, wherein the plurality of internal voids comprises a regular array of honeycomb voids extending between opposing walls of the elongate body.

16. The crib element of claim any one of claims 13 to 15, further comprising an internal plate disposed midway between a top face and a bottom face of the elongate body, wherein the internal plate closes the honeycomb voids at a central plane of the elongate body.

17. The crib element of any one of claims 13 to 16, wherein the coupling elements comprise notches angled at other than perpendicular and disposed at each end and on top and bottom faces of the elongate body.

18. A method of forming a crib component for assembly into a hollow crib column, the method comprising: forming a first elongate crib element from a moulding or additive process, the first elongate crib element including a polymer material with a plurality of internal voids for reducing mass and coupling notches angled at other than perpendicular and disposed at each end and on top and bottom faces of the elongate crib element; and cutting the first crib element along a midway point between top and bottom faces to provide a second half-component which can fit between other first full crib elements for providing a flush and flat upper crib columnar roof surface.

19. The method of claim 18, wherein the first elongate crib element further comprises an internal plate disposed at the midway point between the top and bottom faces, such that cutting along the midway point provides a closed surface on both the first and the second halfcomponent.

20. The method of claim 18 or 19, wherein the plurality of internal voids comprises a regular array of honeycomb voids extending from the top face to the internal plate and from the bottom face to the internal plate.

21. The method of claim 18 or 19 or 20, wherein the coupling notches are configured to connect the first elongate crib element to like elongate crib elements at an angle of approximately 120 degrees to facilitate formation of a hexagonal hollow crib column.

22. The method of any one of claims 18-21, wherein the polymer material is selected from the group consisting of polypropylene, polyethylene, acetal, polycarbonate, ABS, PPS, TPU, PEEK, and acrylic, and the moulding or additive process comprises injection moulding or 3D printing.

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