Rock Dusting Composition with Polymer for Mine Fire Suppression
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Solution Overview
Problem
Existing rock dusting methods in coal mines face challenges with airborne dust during application and inadequate dispersion in blast situations, leading to inefficiencies in preventing and suppressing fires and explosions.
Innovation Solution
A composition comprising rock dust, water, a pumping aid, and a polymer is applied to mine surfaces, allowing it to dry into a non-cohesive mass that disperses as a fine powder upon ignition, effectively suppressing flames and explosions by creating a rock dust-air suspension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If dry rock dust is spread onto mine surfaces, then the application process generates excessive airborne dust requiring evacuation, but wet rock dust compositions create a cohesive mass that does not disperse properly in blast situations
Solution Approach 1:
The patent changes the water content parameter to a specific range (15-40 weight percent) that is sufficient to enable pumpability and adhesion during application but low enough to allow proper drying and dispersion in blast situations. This parameter optimization resolves the contradiction between minimizing airborne dust during application and ensuring proper dispersion characteristics when dried.
Solution Approach 2:
The patent creates a composite rock dust composition by combining rock dust particles with water and polymer additives. This composite structure allows the material to exhibit non-cohesive properties when dried, enabling proper dispersion in blast situations while minimizing airborne dust generation during application through the binding effects of the polymer and optimized water content.
2Ease of manufacture
If excessive water is added to rock dust to enable pumpable mixture, then the mixture becomes pumpable and spreadable, but the dried product sloughs to the mine floor instead of adhering to surfaces
Solution Approach 1:
The patent optimizes the water content parameter to a specific range (15-40 weight percent) that provides sufficient fluidity for pumpability and spreadability while maintaining low enough moisture levels to ensure proper adhesion after drying. This parameter control prevents both the mixture from being too thick to pump and the dried product from sloughing off surfaces.
Solution Approach 2:
The patent introduces polymer additives as intermediary substances that facilitate adhesion between the rock dust-water mixture and mine surfaces. These polymers act as binding agents that maintain the mixture's pumpability while ensuring reliable adhesion of the dried product to surfaces, preventing sloughing to the mine floor.
3Reliability
If rock dust is applied to prevent fire and explosion, then fire suppression capability is improved, but the application process itself creates hazardous airborne dust conditions
Solution Approach 1:
The patent employs hydraulic spraying methods to apply the rock dust composition. By using water-based slurry delivery systems, the process minimizes airborne dust generation during application while ensuring effective coverage of mine surfaces with the fire-suppressing rock dust material.
Solution Approach 2:
The patent changes the physical state parameter of the rock dust from dry powder to wet slurry form during application. This parameter change eliminates airborne dust hazards during the application process while maintaining the fire suppression capabilities of the rock dust. The optimized water content ensures the slurry can be properly applied and then dries to provide effective fire protection.
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 solution minimizes airborne dust during application, ensures efficient dispersion in blast situations, and provides effective fire suppression without the need for evacuation, while maintaining the properties of traditional stone dusting.
Implementation Method 1
flocculating the composition under flocculation conditions sufficient to form agglomerated particles. The agglomerated particles comprise polymer chains having rock dust particles attached thereto
Implementation Method 2
the low water content of the composition permits evaporation of the water, resulting in a dry mass of fine, poorly-cohesive, material that dusts readily
Implementation Method 3
a concussion from an explosion and/or fire causes at least a portion of the rock dust to detach from the polymer chains to produce a rock dust-air suspension that suppresses propagation of a flame and/or fire
Data Source
AI summary
A rock dusting composition composed of rock dust, e.g., limestone or other mineral dust, water, pumping aid, and polymer, e.g., acrylamide homopolymers, acrylamide copolymers, and combinations thereof, and a method for applying the composition to the surface of a mine. The composition has a water content and a polymer content sufficient to allow the polymer to (i) disperse water molecules within the composition and, upon drying of the composition, (ii) dissipate forming void spaces in the dried composition. The composition is useful for suppressing propagation of a flame and/or fire caused by ignition of coal dust and/or gas within a coal mine.