Coal Combustion Byproducts-Based Artificial Mine Supports - Recent Developments

Chugh, Y. P.
Organization: International Conference on Ground Control in Mining
Pages: 10
Publication Date: Jan 1, 2004
The use of wooden supports, supplementary to the primary method of roof control using roof bolts in mines, consumes over 3 million cubic meters of hardwood in the U.S. annually. These supports arc primarily used in the form of cribs and posts. Along with a rapid depletion of high quality timber resources, supplies fluctuate seasonally, costs are escalating rapidly, and product quality is highly variable. Environmental considerations of global climate change put additional pressure on deforestation for utilization of timber for artificial supports. On the other hand, management of coal combustion byproducts (GCBs) from power plants has become a major issue to maintaining a healthy coal industry. The USA currently produces over 100 million tons of CCBs annually and the average cost for their management in the US is about $20/ton. This cost is expected to escalate rapidly with tougher environmental regulations. The principal author has been directing research, development, and demonstration studies for CCBs-based artificial supports and lightweight structural materials in mines for the past seven years and has made significant progress toward commercially viable products. More specifically, first and second generation crib elements and post elements have been developed, characterized analytically, and demonstrated in the field. It is estimated that about 2.5 x 10" tons of fly ash could be utilized for artificial supports in U.S coal mines and this would double if these materials were utilized in non-coal mines as well. The author believes that CCBs-based artificial supports have the potential to replace wooden supports and blocks with better performance and cost competitiveness while managing CCBs in an environmentally sound manner. This paper focuses on the development and field demonstration of CCBs-based artificial supports for use in underground mines, and its pilot scale fabrication facility. Recent analysis results on engineering performance evaluation of the developed crib under various loading conditions using finite element method are presented. The following comments highlight the developments: I ). Engineered artificial supports, crib and post elements, using CCBs as a major constituent, have significant potential for application in mines because their structural performance is significantly better than wooden cribs counterparts. 21. Engineered crib elements provide about 50% larger area for air-flow than a conventional wooden crib. 3). Engineered crib elements are not flammable. 4). Each engineered crib element utilizes about 10 kg of fly ash, about 40 % of the weight of crib element- Therefore, a typical crib 2.0 m high utilizes about 200 kg of fly ash. 5). Each 16.5 cm diameter engineered post utilizes 50 kg of fly ash. 6). Assuming 3.0 million cu. meter of wood consumed for post and crib support systems, it is estimated that about 4 - 5 million tons of fly ash may be utilized for supports fabrication in the USA. 7). An engineered post has excellent post-failure characteristics similar to wood. In addition, the engineered post also has excellent loading and unloading characteristics close to the yield point of about 75% of the ultimate load carrying capacity.
Full Article Download:
(3142 kb)

Additional chapters/articles from the SME-ICGCM book 23rd International Conference on Ground Control in Mining (ICGCM) 23rd

Geomechanical Criteria of Longwall Face Support Selection at
Rock Fracture, Caving and Interaction of Face Supports Under
Effect of the Approaching Longwall Faces on Barrier and Entr
Computer Simulation of Ground Behaviour and Rock Bolt Intera
lnterpanel Barriers for Deep Western U.S. Longwall Mining
Application of Yieldable and Cuttable Pump Crib in Longwall
Field Testing of a Real Time Roof Mapping Drilling Display S
Problems in "Void" Detection in Coal Mine Water Hazards
Violent Coal Pillar Collapse -A Case Study
Stooping Low Safety Factor Pillars at Goedehoop Colliery - 1
Laboratory Strength Testing of Coal from Selected Illinois S
Downhole Overcoring Stress Measurement at a Western Undergro
Effect of In Situ Stresses on the Stability of Coal Mine Dev
SOMA: A New Method to Calculate the Operative Stress Field:
Numerical Modeling for Increased Understanding of the Behavi
Evaluation of Rockburst Hazard from Core Testing
Investigation of Electromagnetic Emissions in a Deep Undergr
Development and Application of Geotechnical and Rockmechanic
Laboratory Testing of Rib Straps
The New Two-Dimension LaModel Program
Risk Assessment: Multiseam - Single Seam Mining
A Method To Determine Expander Spacing For Steel Pipelines I
A Case Study Of Abandoned Mine Subsidence At Dominion, Nova
Spatial Trends In Rock Strength - Can They Be Determined Fro
Development And Demonstration Of An Alternate Mining Geometr
Evaluation Of Polyurethane Injection For Beltway Roof Stabil
Application Of Ground Penetrating Radar To Evaluate The Exte
A Risk Assessment Tool For Open Cast Mining In South Africa
Analysis Of Practical Ground Control Issues In Highwall Mini
Preventing Falls Of Ground In Coal Mines With Exceptionally
Geo-Mechanical Property And Failures Of Weak Roof Shales In
Eclipse System Bolting In The Illinois Basin
Variation In The Load Transfer Of Fully Encapsulated Rockbol
Bolt Load Changes During Initial Face Advance And Cross-Cut
Coal Mine Primary Support Selection: Tension Versus Non Tens
Improving Stope Support At Modikwa Platinum Mine
3D FEM Simulation For Fully Grouted Bolts
An Investigation Into The Effectiveness Of Support Systems C
Hydraulic Prestressing Units: An Innovation In Roof Support
Improving Roof Truss Performance
Coal Combustion Byproducts-Based Artificial Mine Supports -
The Influence Of Horizontal Stress On Pillar Design And Mine
Investigation Of Pillar-Roof Contact Failure In Northern App
Mapping Hazards With Microseismic Technology To Anticipate R
Practical Detection Of Underground Mine Roof Failure
Heat-Imaging Experimental Study Of Reducing Local Gas Accumu
Microcirculation Theory Analysis Of Spontaneous Combustion O