Shear-Thinning Explosive Suspension for Upward Borehole Loading
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Solution Overview
Problem
Loading upward boreholes with water-based explosive mixtures is challenging due to the need for high viscosity to prevent flow, which increases pressure drop in hoses and complicates logistics, while existing solutions either fail to provide sufficient viscosity increase or are slow, leading to inefficient pumping and retention issues.
Innovation Solution
A water-based explosive suspension with shear-thinning rheological behavior, composed of an aqueous solution of oxidizing salts and water-soluble polymers, such as galactomannans or xanthan gums, that exhibits high viscosity when still and low viscosity during pumping, facilitated by the inclusion of oxidizing salt particles and optional fuel and sensitizer components, along with gas bubbles or porous particles to enhance self-sustaining properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the viscosity of the explosive is increased to prevent flow in upward boreholes, then the explosive can self-sustain without flowing due to gravity, but the pressure drop in the loading hose increases excessively
Solution Approach 1:
The explosive suspension exhibits dynamic rheological behavior where its viscosity changes based on shear rate. During pumping, high shear rates maintain low viscosity for easy flow through hoses. After loading, low shear rates allow viscosity to increase naturally, enabling the explosive to self-sustain in upward boreholes without excessive pressure drop during loading.
Solution Approach 2:
The invention changes the physical parameter of viscosity from a static property to a dynamic one that responds to shear rate. By formulating the explosive with specific polymers and additives, the viscosity parameter automatically adjusts according to the flow conditions, being low during pumping and high during storage.
2Stability of the object's composition
If the viscosity of the explosive is increased to prevent flow in upward boreholes, then the explosive can be retained in the borehole, but the logistics and handling of the product become greatly complicated
Solution Approach 1:
The explosive suspension exhibits dynamic rheological behavior where its viscosity changes based on shear rate. During pumping, high shear rates maintain low viscosity for easy flow through hoses. After loading, low shear rates allow viscosity to increase naturally, enabling the explosive to self-sustain in upward boreholes without excessive pressure drop during loading.
3Stability of the object's composition
If existing solutions are used to increase viscosity, then some viscosity increase is achieved, but the process is slow and pumping efficiency is reduced
Solution Approach 1:
The explosive is formulated in advance with polymers and additives that provide immediate shear-thinning behavior upon mixing. The viscosity modification occurs during the pumping process itself rather than requiring a separate slow thickening step, maintaining high pumping efficiency while achieving the required viscosity for borehole retention.
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 suspension effectively self-sustains in upward boreholes without flowing due to gravity, while maintaining reasonable pumping pressures, ensuring efficient loading and retention, with a significant increase in viscosity upon standing, thus addressing the logistical and operational challenges of loading upward boreholes.
Implementation Method 1
one or more water-soluble polymers which can bring about a shear-thinning-type behavior
Implementation Method 2
Once introduced in the borehole, the suspension can transform into explosive by means of generating gas bubbles by means of a chemical gasification process.
Data Source
AI summary
The present invention relates to a water-based non-sensitized matrix or explosive suspension which itself has a rheological behavior such that it allows mechanically loading upward boreholes. This suspension behaves like a viscous liquid when it is forced to flow due to the action of a loading pump, and, however, has the characteristics of a soft solid when it is on standby once inside the borehole. The composition essentially consists of an aqueous solution of oxidizing salts and optionally water-soluble fuels and/or sensitizers, and one or more water-soluble polymers conferring the desired rheological characteristics. Particles of oxidizing salts with a grain size such that they enhance the rheological behavior characteristic of the suspension are dispersed in this aqueous solution.