The treatment of post-mining goafs presents a significant challenge for the coal industry,grappling with environmental safety and carbon neutrality goals.To address issues such as abandoned goafs,high carbon emissions...The treatment of post-mining goafs presents a significant challenge for the coal industry,grappling with environmental safety and carbon neutrality goals.To address issues such as abandoned goafs,high carbon emissions,and conflicts in backfill operations during coal mining,this study proposes a CO_(2)mineralization grouting method that targets voids in post-mining goafs.A two-stage mineralization process was designed with a focus on in-situ goaf grouting using open-pore materials.Grouting materials were prepared from carbide slag and fly ash,with cetyltrimethylammonium bromide(CTAB) as a surfactant and oleic acid acts as a foam stabilizer to regulate the pore structure alongside hydrogen peroxide(H_(2)O_(2)) used to regulate the pore structure.Scanning electron microscopy,nuclear magnetic resonance,unconfined compressive strength tests,and random forest regression identified the optimal mix:CTAB=1.2 g,oleic acid=5.0 g,H_(2)O_(2)=1.0g, water-to-solid ratio=0.7,Si/Al and Na/Al molar ratios are controlled at 3.0 and 2.7,respectively.Results from custom-built testing devices showed that open-pore materials doubled the mineralization depth compared with closed-pore materials.The method demonstrates technical feasibility and economic viability,while emphasizing the importance of rigorous risk management to ensure environmental and operational sustainability.Compatible with existing green mining systems,it offers economic and environmental benefits,providing a novel approach for low-carbon coal mining.展开更多
An integration processing system of three-dimensional laser scanning information visualization in goaf was developed. It is provided with multiple functions, such as laser scanning information management for goaf, clo...An integration processing system of three-dimensional laser scanning information visualization in goaf was developed. It is provided with multiple functions, such as laser scanning information management for goaf, cloud data de-noising optimization, construction, display and operation of three-dimensional model, model editing, profile generation, calculation of goaf volume and roof area, Boolean calculation among models and interaction with the third party soft ware. Concerning this system with a concise interface, plentiful data input/output interfaces, it is featured with high integration, simple and convenient operations of applications. According to practice, in addition to being well-adapted, this system is favorably reliable and stable.展开更多
According to the special requirements of secondary mining of resources in gateway-and-pillar goal in extra-thick seams of Shanxi, this paper presents a technical proposal of back stoping from level floors. Numerical s...According to the special requirements of secondary mining of resources in gateway-and-pillar goal in extra-thick seams of Shanxi, this paper presents a technical proposal of back stoping from level floors. Numerical simulation and theoretical analysis are ccsed to investigate the compaction characteristics of cavities under stress as well as an appropriate mining height of the primary-mining layer based on dif- ferent mining widths and pillar widths. For Yangjian coal mine, the mining thickness of the first seam during back stoping from level floor is determined to be 3 m, which meets the relevant requirements. Gateway-and-pillar goaf of a single layer has a range of influence of 9 m vertically. If gateway-and-pillar goaf occurs both in 9-1 and 9-5 layers, the range is extended to within 11.2 m. When the mining width of a gateway is less than 2 m or larger than 5 m, the gateway-and-pillar goal in the upper layer of the primary-mining seam can be filled in and compacted after stoping. When the working face is 2 m away from the gateway and pillar before entering into it and after passing through it, the coal body under the gateway and pillar is subjected to relatively high stress. During mining of the upper layer, moreover, the working face should interlock the goaf in primary-mining layer for 20 m.展开更多
基金supported by the National Natural Science Foundation of China(No.52304198)National Key Research and Development Program(Nos.2023YFC3009100 and 2023YFC3009102)
文摘The treatment of post-mining goafs presents a significant challenge for the coal industry,grappling with environmental safety and carbon neutrality goals.To address issues such as abandoned goafs,high carbon emissions,and conflicts in backfill operations during coal mining,this study proposes a CO_(2)mineralization grouting method that targets voids in post-mining goafs.A two-stage mineralization process was designed with a focus on in-situ goaf grouting using open-pore materials.Grouting materials were prepared from carbide slag and fly ash,with cetyltrimethylammonium bromide(CTAB) as a surfactant and oleic acid acts as a foam stabilizer to regulate the pore structure alongside hydrogen peroxide(H_(2)O_(2)) used to regulate the pore structure.Scanning electron microscopy,nuclear magnetic resonance,unconfined compressive strength tests,and random forest regression identified the optimal mix:CTAB=1.2 g,oleic acid=5.0 g,H_(2)O_(2)=1.0g, water-to-solid ratio=0.7,Si/Al and Na/Al molar ratios are controlled at 3.0 and 2.7,respectively.Results from custom-built testing devices showed that open-pore materials doubled the mineralization depth compared with closed-pore materials.The method demonstrates technical feasibility and economic viability,while emphasizing the importance of rigorous risk management to ensure environmental and operational sustainability.Compatible with existing green mining systems,it offers economic and environmental benefits,providing a novel approach for low-carbon coal mining.
基金Project(51274250)supported by the National Natural Science Foundation of ChinaProject(2012BAK09B02-05)supported by the National Key Technology R&D Program during the 12th Five-year Plan of China
文摘An integration processing system of three-dimensional laser scanning information visualization in goaf was developed. It is provided with multiple functions, such as laser scanning information management for goaf, cloud data de-noising optimization, construction, display and operation of three-dimensional model, model editing, profile generation, calculation of goaf volume and roof area, Boolean calculation among models and interaction with the third party soft ware. Concerning this system with a concise interface, plentiful data input/output interfaces, it is featured with high integration, simple and convenient operations of applications. According to practice, in addition to being well-adapted, this system is favorably reliable and stable.
基金Financial support for this work was provided by the National High-Tech Research and Development Program of China (No. 2012AA062101)the Priority Academic Development Program of Jiangsu Higher Education Institutions (No. SZBF2011-6-B35)the Graduate Students Innovation Fund of Colleges and Universities in Jiangsu Province (No. CXZZ12_0950)
文摘According to the special requirements of secondary mining of resources in gateway-and-pillar goal in extra-thick seams of Shanxi, this paper presents a technical proposal of back stoping from level floors. Numerical simulation and theoretical analysis are ccsed to investigate the compaction characteristics of cavities under stress as well as an appropriate mining height of the primary-mining layer based on dif- ferent mining widths and pillar widths. For Yangjian coal mine, the mining thickness of the first seam during back stoping from level floor is determined to be 3 m, which meets the relevant requirements. Gateway-and-pillar goaf of a single layer has a range of influence of 9 m vertically. If gateway-and-pillar goaf occurs both in 9-1 and 9-5 layers, the range is extended to within 11.2 m. When the mining width of a gateway is less than 2 m or larger than 5 m, the gateway-and-pillar goal in the upper layer of the primary-mining seam can be filled in and compacted after stoping. When the working face is 2 m away from the gateway and pillar before entering into it and after passing through it, the coal body under the gateway and pillar is subjected to relatively high stress. During mining of the upper layer, moreover, the working face should interlock the goaf in primary-mining layer for 20 m.
