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|An underground mining method for extracting an eight metre (26') coal horizon, containing a sandstone layer. A decrease in the thickness of the rock strata between the number two and number three seams of the Sasolburg Coal Field, has resulted in a total mining horizon approximately eight metres (26') thick. This parting varies in thickness and competency and in some areas is impractical to cut with a continuous miner. In addition, the general mining area is highly jointed. The top seam is first mined to a normal bord and pillar plan with a continuous miner. The bottom seam is then mined by selectively undercutting the stone parting constituting the floor of the top seam. In areas where this parting is between 0.75 - 2.50 metres (29.5" - 98") thick, it is suspended from the primary roof support installed when mining the top seam. Secondary, high extraction retreat mining is then undertaken in the coal pillars adjacent to the suspension supported headings in the bottom seam. Left in-situ, the parting provides lateral support to the pillar sidewalls in both the top and bottom seams, enabling high percentage extraction rates in what was previously thought an uneconomically mineable area. The paper proposed, presents the challenges and practical implications of executing the mining method, including the primary roof control of the top seam and the stone parting between scams.|
Additional chapters/articles from the SME-ICGCM book 22nd International Conference on Ground Control in Mining (ICGCM) 22nd
|Pillar Design and Roof Support for Controlling Longwall Head||Stress Analysis and Support Design for Longwall Mine-Through||The Utilisation of Numerical Modelling to Predict Water and||Longwall Roof Fall Prediction and Shield Support Recommendat||Comparison Of Multiple And Single Entry Roadways For Highly||Numerical Modeling Of Longwalls In Deep Coal Mines||The Characteristics Of Mining-Induced Fractures In Overlying||Design And Experience Of Total Extraction Room And Pillar Op||Using Site Case Histories Of Multiple Seam Coal Mining To Ad||Mining Method For Extracting An Eight Metre Coal Horizon Con||Stooping Low Safety Factor Pillars At Goedehoop Colliery||Modelling Of Pillar Stability In Room And Pillar Mines||Pillar Optimization For Initial Design And Retreat Recovery||Application Of RMT's Remote Reading Telltale System To||Rock Mechanics Study Of Lateral Destressing For The Advance-||New Tools For Roof Support Evaluation And Design||Considerations For Using Roof Monitors In Underground Limest||Mine Roof Geology Information System (MRGIS)||Imaging Ahead Of Mining With Radio Imaging Method (RIM-IV) I||Geophysics For The Detection Of Abandoned Mine Workings||Investigation Of Seam Thickness And Seam Splitting Within A||Determination Of Rock Strength Properties Using Geophysical||RQD from the Barrel to the Box: Weatherability May be a Bett||A probabilistic approach to ground support design in undergr||The Requirements of a Database to Store Geotechnical Data to||Variation of Horizontal Stresses and Strains in Mines in Bed||Geotechnical Planning Basis for the Optimization of Workings||Tensile roof failure arising from horizontal compressive str||Study of load transfer capacity of bolts using short encapsu||Intersection Stability and Tensioned Bolting||Premature Rock Bolt Failure Through Stress Corrosion Crackin||Short-encapsulation Pull Tests for Roof Bolt Evaluation at a||Field Test with Strain-gauged Friction Bolts at the Gold Hun||Directional Rock Bolt Pullout Tests as Index Tests for Estim||Eclipse Bolting System||The Application of Pre-tensioned Grouted Tendons at Harworth||Investigation into the Extent and Mechanisms of Gloving and||Developments in Improving the Standard of Installation and B||Development of Geotechnical Procedures for the Analysis of M||Recent Developments in the Use of Seismic Tomography in Long||Pumpable Roof Supports: Developing Design Criteria by Measur||Design Considerations of the Secondary Roof Support for Long||The Effect of Standing Support Stiffness on Primary and Seco||Numerical Modeling of the U1A Complex at the Nevada Test Sit||Rock Mechanics and the Analysis of Underground Mine Stabilit||A Study of Potential Fault Reactivation and Water Intrusion||The Elimination of Rock-fall Fatalities in Ontario Hardrock||Root Causes of Groundfall Related Incidents in U.S. Mining I||Analysis on the Dynamics of Mining Subsidence in Range of a||Mitigating Subsidence Influences on Residential Structures C||Influences of Longwall Subsidence on a Guyed Steel Tower - A||Surface Movement of Super-wide Longwall Panels Using Top-coa||New Approach to Evaluate the Stability of Yield Pillars||Experimental Study of Acoustic Emission Characteristics for|