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SME-ICGCM (1801)
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TITLE A History of Bock Burst Research in the Coeur D'Alene Mining District
SUMMARY This paper reviews the history of rock burst research in the Coeur d'Alene Mining District of northern Idaho over the last 30 years. Rock bursting is a problem because of a combination of geological factors in the region--complex structure, high horizontal stresses, and strong, brittle rock that readily stores strain energy. The Bureau of Mines has cooperated with industry to study rock burst phenomenon for many years. Early work focused on methods to mitigate bursting problems within the contex...
AUTHOR Jenkins, Michael
TITLE Field Measurements of Overburden and Chain Pillar Response to Longwall Mining
SUMMARY Current longwall pillar design relies heavily upon past experience and many assumptions about pillar and entry response to longwall abutment pressures. Caving characteristics of the immediate and main roof strata are known to play an important role in the overall pressure redistribution, which determines the maximum abutment pressure, abutment pressure at the T-junction, and the width of influence zone. This paper presents the results of an extensive geomechanical study in a longwall panel a...
AUTHOR Su, Daniel W. H.
TITLE Chemical Destressing to Alleviate Rockbursts
SUMMARY Destress blasting is commonly used in the mines to minimize the occurrence of rockbursts. The fracturing created by destressing in the vicinity of the face reduces the stress concentration by pushing the zone of high stress deeper into the rock mass. But the destressing practice by blasting may be devastating near the faults or other sensitive high stress zones. To avoid severe rockbursts in such situations, the application of chemical destressing has been proposed in this paper. A laboratory...
AUTHOR Singh, S. P.
TITLE A Method for Sizing Longwall Pillars Based on Field Measurements
SUMMARY A new method for the design of longwall pillars, called"Analysis of Longwall Pillar Stability"(ALPS), is described. The method is the final result of a research program that included two major field studies, extensive reanalysis of data from other in situ measurements, and detailed evaluations of available pillar design methods. The key problem addressed by ALPS is estimation of the abutment loads applied to longwall pillars. Based on underground stress measurements made in mines in three sta...
AUTHOR Mark, Christopher
TITLE Rockburst Control Measures at INCO's Creighton Mine
SUMMARY Rockburst conditions were first encountered at Inco's Sudbury area operations in the mid 1930's when mining advanced to below the 610 m (2000 ft.) horizon. Now, mining is being carried out at depths down to 2130 m (7000 ft.) at Inco'a Creighton Mine. While rockburst potentials have increased with depth. improvements in mine planning, methods, support systems and developments in destressing have alleviated the condition to where it is less of a problem now than it was in the early years. Hang of ...
AUTHOR Oliver, P.
TITLE The Initial Collapse of the Overburden Over Longwall Panels
SUMMARY Documented case histories are studied where data were found on the initial collapse of the overburden above the longwall panels. Under this scenario, the most controlled conditions exist for assessing the span capacity of the overburden (i.e., before failure the roof spans to fin coal abutments on two to all four sides). In an attempt to correlate theory to field observations, data are used on the overburden lithology, and the depth, width, and face advance of the panel, as well as, the subsi...
AUTHOR Marino, Gennaro
TITLE The Strong Outbursts of Coal and Gas in Coal Mines in China
SUMMARY China has at least 200 collieries suffering from the problem of instantaneous outbursts of coal and gas. The strong outbursts often occurred in active tectonic lanes and areas of high stress concentration. In this paper, the author describes some characteristics of the strong outbursts and analyses the effects of ground stress, gas pressure and the properties of coal in outbursts.
AUTHOR Zhow, S. N.
TITLE Geologic Conditions Affecting Mineability in the Jane Mine.
SUMMARY Geologic conditions in eight northern operating sections of Jane Mine, Keystone Coal Mining Complex. Armstrong County, Pennsylvania are defined by utilizing drillhole data and underground geologic mapping. Three of the eight sections are experiencing difficult mining conditions in the Shelocta"0"coal seam (formerly the Lower Freeport). The five remaining productive sections will exhaust their reserves within one year. Coordinating mine planning with future production levels is aided by indicatin...
AUTHOR Harven, Stephen J.
TITLE Mechanisms of Chimney Subsidence Over Abandoned Coal Mines
SUMMARY Mining related subsidence is a major concern over abandoned shallow coal mines. Many of the subsidence prone areas are presently used or will be used in the future for residential housing development. Concern over mine subsidence is inhibiting the development of surface land uses on previously mined area. This concern prompted public officials to realize the need to develop guidelines which can be used to assess and reduce the risk of mine subsidence damage to building and other improvements. Su...
AUTHOR Karfakis, Mario G.
TITLE Factors Influencing the Occurrence of Coal Pillar Bumps at the 9-Right Section of the Olga Mine
SUMMARY The Bureau of Mines conducted research at the 9-Right Section of the Olga Mine to determine the cause of bumps and aid in the development of appropriate control techniques. The purpose of this paper is to identify the factors which affect the occurrence of bumps at the Olga Mine. These factors have been broken down into two categories, in situ and mining related. The in situ factors include those conditions which exist prior to mining, such as variations in lithology and overburden, presence of...
AUTHOR Oyler, David C.