Hybrid Irrigation System for Heap Leaching
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Solution Overview
Problem
Existing heap leaching methods face inefficiencies in solution delivery to low-permeability ores like nickel/cobalt laterite, leading to sub-optimal water and reagent use, heat loss, and surface degradation, particularly in high clay content ores where evaporation and scaling complicate solution distribution.
Innovation Solution
A hybrid irrigation system combining surface and sub-surface delivery of leach solutions using a main conduit with surface emitters and sub-surface applicators that extend into the ore heap, allowing solution delivery at varying pressures and depths to enhance metallurgical performance and reduce evaporation losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If surface sprinklers are used for solution delivery, then solution distribution coverage is improved, but evaporation losses and heat loss increase
Solution Approach 1:
The invention transitions from two-dimensional surface spraying to three-dimensional subsurface injection by extending delivery points into the heap interior at various depths. This dimensional change allows solution delivery below the evaporative zone while maintaining comprehensive coverage through multiple injection points distributed throughout the heap volume.
Solution Approach 2:
The subsurface delivery system acts as an intermediary between the surface application system and the deep heap zones. By injecting solution through conduits embedded in the heap structure, the system mediates between the need for surface coverage and the need to minimize evaporation, delivering solution directly to target zones without exposure to atmospheric conditions.
2Loss of substance
If surface drip irrigation is used, then water usage efficiency is improved, but preferential flow paths limit reagent delivery at depth
Solution Approach 1:
The invention segments the solution delivery function across multiple depth zones by installing delivery points at various depths throughout the heap. This segmentation prevents preferential flow paths from dominating the entire flow path, as solution is introduced at multiple levels to reach different zones efficiently, ensuring both water efficiency and adequate reagent delivery to depth.
Solution Approach 2:
The invention adds the depth dimension to solution delivery by extending delivery points into the heap interior. This transforms the system from surface-only (2D) to subsurface-inclusive (3D) delivery, enabling direct reagent introduction to deep zones while maintaining the water efficiency benefits of drip irrigation through controlled release at multiple depths.
3Speed
If high pressure solution delivery is used, then penetration into low permeability ores is improved, but surface degradation and scaling increase
Solution Approach 1:
The invention extracts the high-pressure injection function from the surface environment and relocates it to subsurface zones through embedded conduits. By taking out the high-pressure delivery mechanism from surface exposure, the system achieves rapid penetration into low-permeability ores through subsurface injection points while eliminating the harmful surface effects of high-pressure spraying such as degradation and scaling.
Solution Approach 2:
The subsurface conduit system serves as an intermediary that transmits high-pressure solution from the surface supply system to deep heap zones without exposing the heap surface to high-pressure effects. The conduits mediate between the need for high-pressure penetration and the need to protect the surface, delivering forceful injection internally while keeping the surface intact.
4Quantity of substance
If extended leach cycles are used to improve reagent delivery, then metal recovery is improved, but productivity decreases
Solution Approach 1:
The invention performs preliminary action by pre-distributing solution throughout the heap structure using subsurface delivery points before formal leaching begins. This preliminary subsurface wetting and reagent distribution ensures rapid and uniform penetration from the start, eliminating the need for extended leach cycles to achieve adequate penetration, thus maintaining high productivity while maximizing metal recovery.
Solution Approach 2:
The invention establishes continuity of useful action by maintaining active solution delivery throughout the heap volume via multiple subsurface points rather than relying on slow percolation over extended periods. This continuous multi-zone delivery ensures sustained metal extraction at high rates, improving both recovery and productivity by keeping the entire heap volume actively engaged in leaching simultaneously.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The hybrid system improves metallurgical performance, reduces leach cycle times, conserves water, and maximizes metal recovery by ensuring uniform solution distribution and reducing heat loss and scaling issues, suitable for both low and high permeability ores.
Implementation Method 1
The sub-surface solution applicators can be configured to deliver leach solution at preset pressures, such as below atmospheric pressure, at atmospheric pressure, or above atmospheric pressure.
Implementation Method 2
Problems associated with the use of sprinklers are evaporation, heat loss, wind loss, and potential damage to the surface of the heap.
Implementation Method 3
The present invention is relevant to percolation leaching of metal or mineral ores.
Data Source
AI summary
An improved method and system is described for applying a leach solution to ore in the process of heap leaching. The Hybrid Irrigation System (HIS) relies on both surface solution delivery techniques as well as sub-surface solution application to improve the solution uniformity and metallurgical performance of a leaching process. The methods and systems allow for controlled application of leach solution with a hydraulic head applied that can be adjusted or varied depending on the conditions of the ore from negative, atmospheric or positive pressure, while distributing leaching solution in a uniform manner independent of surface variability with respect to elevation and infiltration capacity of the ore surface. The systems and methods have particular application to low permeability ores like high clay content copper, silver, uranium, and gold ores and nickel/cobalt laterite, but can be used in any heap leach application where control must be maintained with respect to surface ponding, stability and accessibility, and uniform reagent distribution, resulting in improved leaching performance.