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Abutment pillar ‘notching’ improves abutment tunnel roof conditions at the Cayuga rock salt mine
Z3A
cf mi~ing seams, faults ~esent, sulph~ content of coal, type ar~ thickness Of floor rocks, ar~ water ir~lux. Predictions are made by adding these weig~htings. 831103 s~x~Y DRIFTS: G~YUND TREATMENT WITH PARTICULAR ~ E TO F R Y I N G TECHNIQUE Fc~rest, W In: Tunnelling 82, Proceedings of the 3rd International Symposium, ~ri~hton~ 7-ii June 1982, PI17-120. Publ Lonlon: YMM, 1982 Describes the driving of surface drifts at Gascolgne Wood through difficult strata with large q~mtities Of water im~esent~ with particular reference to the !~ogress Of the drifts through grouted Lower Magnesian Limestone ani the frozen Basal Sanis. The eventual thawing of the Basal Samds and the monltoring Of ice wall decay and the l~hysical effect on the drifts themselves are er~lysed.
83no~
DRI~DRMNG IN METAL MINES IN CHINA Yu Zeshemg~ Shao H w ~ i e In: Tunnelling 82, Proceedings cf the 3rd International Symposit~m, Brighton~ 7-I1 June 1982, P255-260. Publ Lo~on: I~4, 1982 A general review of the development of drifting in China over the past 30 years incl~ling: improvements in drilling a~i blasting, l ~ a ~ ~r~ hauling equipment a~i support methods (the introduction of rock bolts ~ shetcreting).
831105 IMPROVED DESIGN OF COAL PILLARS FOR US MINING CONDITIONS Bieniawski, Z T Proc I st Conference on G r ~ Control in Mining, Morgantow~, 27-29 July 1981, P1322. Publ Morgarrtc~rn: West Virginia University# 1981 Presents the results Of a survey ~f room pillar dimensions and design l~ractice in US coal mines aimed at Improving the design Irocedures in roc~ amd piller mining. A review is given of current pillar strer~h f~rmulae and it is suggested that selection of a more al~ro~riate pillar strength formula and more realistic safety factors can lead to better pillar design. 25 refs.
831106 REVIEW OF PILLAR DESIGN EQUATIONS INCLUDING THE EFFECTS OF CONSTRAINT Babcock, C; Morgan, T; Haramy~ K Proc 1st Conference on Groumd Control in Mining, Mcrgantown, 27-29 July 1961, P233~. Publ Morgantown: West Virginia University, 1981 Reviews equations for mine pillar design from 1833 to the l~esent. Most of the equations are of essentially the same kimd, using pillar ~Idth to height relationships. The effects of er~ constraint and test volume size~ that were implied in same of these early equations have received special emphasis in recent years. The apparent increase in s ~ r e r ~ resultir~ for confined testing should be sepsrated from the actual coal strength Of unoonfined tests to emphasise that the increased s t r e r ~ exists in pillars only as long as the constraint exists. The sizes of pillars defined by the relationships Of Wilson amd Wardell are compared. While the Wilson l~llars average onehalf cf the area of the Wardell pillars for depths from 200 to 3,000 feet, the charge in behavior is not this drastic. ~i refs.
• ~.s 20/I--e
831107 ABUTME~ PILLAR 'NOTCHING' IMPROVES ABUTMEBT TUNNEL ROOF CONDITIONS A T THE CAYUGA ROCK SALT MINE Flumeau, D B; Petersen, G B Proc 1st Conference on Ground control in Mining, Morgantown, 27-29 July 1981, 1=3543. Publ Morgantown: West Virginia University, 1981 The Cayuga Mine changed from a standard room amd pi1!-r mine design to a yielding pillar/press~e arch design five years ago. In @eneral the roof conditions improved. However, entries adjacent to the abutment pillars continued to fail. It was noticed that where abutment pillars were accidentally 'notched', the abutment entries had better roof coalitions than where there were no 'notches'. Experiments with intentionally notched abutment pillars showed that notching did Improve abutment entry conditions and also reduced costs because it was not necessary to bolt the notches.
8311o8 INFLUENCE
OF CERTAIN GEOLOGIC AND GEOTECHNICAL FACTORS ON COAL MINE FLOOR STABILITY. A C A ~ STUDY Speck, R C Proc ist Comferemce on Grouni Control in ;flming, Morgsatown, 27-29 JUly 1981, I ~ ~9. Publ Morgantown: West Virginia University, 1981
St~xlles to investigate floor heave at the Zelgler Coal Compax~ No. 5 a~l Murdock room a~i pillar mines were carried out. Floor heave phenomenon were found to occur where there was a combination of critical factors, ir~luling low urderclay cohesive streDgth, low claystone cohesive strength, low ratio Of u~ierclay to claystone cohesive strer4~th, thick underclay stratum, and high pill~r stresses. High natural water content was found to be an importar~ determinant of ur~erclay and claystone strengths.
831109 STRATA DIS~K~RBANCE PREDICTION FOR MINING ~E~EATH SURFACE WATER AND WA_~E IMPOUNDMENTS Simgh, M M; Kenicrski, F S Proc 1st Conference on Grou~i Control in Mining, Mcrgantcwn, 27-29 July 1981, F7689. P~bl Mc~gantown: West Virginla University, 1981 Modes of strata disturbance iniuced by uniergrourd mining are first discussed: surface s~bsiderite, sinkhole pher~x,er~, subsurface strata movement, char~es in permeability due to strata movement anl surface crack closure. The mechanics Of strata disturbance for mining beneath surface bodies of water are then considered. 831110 ENGINEERING ANALYSIS O F ' S Q U E ~ ' FAILURE OF PILLARS IN THE PITTSBURGH COAL ~ D Mishra, G; Grayson, R L Prom 1st Comfererm.e on Ground Control in M.l.ni~, Mcrtp~t;o~rn, 2'~.-29 J u l y 1981, 1,11~153. Publ Mcr@~ntc~n: West Virginia University, 1981 Presents a case study of the Nemaeolln coal mine, Pezmsylvanla, USA where rapid failure of pillars occurred due to squeeze. The develol~nent of the eq~eeze, its im~ogression in time ar~ analyses of 1:,he cor~Ition are described. The effect of further mlnimg is A~l~Vsed.
cf mi~ing seams, faults ~esent, sulph~ content of coal, type ar~ thickness Of floor rocks, ar~ water ir~lux. Predictions are made by adding these weig~htings. 831103 s~x~Y DRIFTS: G~YUND TREATMENT WITH PARTICULAR ~ E TO F R Y I N G TECHNIQUE Fc~rest, W In: Tunnelling 82, Proceedings of the 3rd International Symposium, ~ri~hton~ 7-ii June 1982, PI17-120. Publ Lonlon: YMM, 1982 Describes the driving of surface drifts at Gascolgne Wood through difficult strata with large q~mtities Of water im~esent~ with particular reference to the !~ogress Of the drifts through grouted Lower Magnesian Limestone ani the frozen Basal Sanis. The eventual thawing of the Basal Samds and the monltoring Of ice wall decay and the l~hysical effect on the drifts themselves are er~lysed.
83no~
DRI~DRMNG IN METAL MINES IN CHINA Yu Zeshemg~ Shao H w ~ i e In: Tunnelling 82, Proceedings cf the 3rd International Symposit~m, Brighton~ 7-I1 June 1982, P255-260. Publ Lo~on: I~4, 1982 A general review of the development of drifting in China over the past 30 years incl~ling: improvements in drilling a~i blasting, l ~ a ~ ~r~ hauling equipment a~i support methods (the introduction of rock bolts ~ shetcreting).
831105 IMPROVED DESIGN OF COAL PILLARS FOR US MINING CONDITIONS Bieniawski, Z T Proc I st Conference on G r ~ Control in Mining, Morgantow~, 27-29 July 1981, P1322. Publ Morgarrtc~rn: West Virginia University# 1981 Presents the results Of a survey ~f room pillar dimensions and design l~ractice in US coal mines aimed at Improving the design Irocedures in roc~ amd piller mining. A review is given of current pillar strer~h f~rmulae and it is suggested that selection of a more al~ro~riate pillar strength formula and more realistic safety factors can lead to better pillar design. 25 refs.
831106 REVIEW OF PILLAR DESIGN EQUATIONS INCLUDING THE EFFECTS OF CONSTRAINT Babcock, C; Morgan, T; Haramy~ K Proc 1st Conference on Groumd Control in Mining, Mcrgantown, 27-29 July 1961, P233~. Publ Morgantown: West Virginia University, 1981 Reviews equations for mine pillar design from 1833 to the l~esent. Most of the equations are of essentially the same kimd, using pillar ~Idth to height relationships. The effects of er~ constraint and test volume size~ that were implied in same of these early equations have received special emphasis in recent years. The apparent increase in s ~ r e r ~ resultir~ for confined testing should be sepsrated from the actual coal strength Of unoonfined tests to emphasise that the increased s t r e r ~ exists in pillars only as long as the constraint exists. The sizes of pillars defined by the relationships Of Wilson amd Wardell are compared. While the Wilson l~llars average onehalf cf the area of the Wardell pillars for depths from 200 to 3,000 feet, the charge in behavior is not this drastic. ~i refs.
• ~.s 20/I--e
831107 ABUTME~ PILLAR 'NOTCHING' IMPROVES ABUTMEBT TUNNEL ROOF CONDITIONS A T THE CAYUGA ROCK SALT MINE Flumeau, D B; Petersen, G B Proc 1st Conference on Ground control in Mining, Morgantown, 27-29 July 1981, 1=3543. Publ Morgantown: West Virginia University, 1981 The Cayuga Mine changed from a standard room amd pi1!-r mine design to a yielding pillar/press~e arch design five years ago. In @eneral the roof conditions improved. However, entries adjacent to the abutment pillars continued to fail. It was noticed that where abutment pillars were accidentally 'notched', the abutment entries had better roof coalitions than where there were no 'notches'. Experiments with intentionally notched abutment pillars showed that notching did Improve abutment entry conditions and also reduced costs because it was not necessary to bolt the notches.
8311o8 INFLUENCE
OF CERTAIN GEOLOGIC AND GEOTECHNICAL FACTORS ON COAL MINE FLOOR STABILITY. A C A ~ STUDY Speck, R C Proc ist Comferemce on Grouni Control in ;flming, Morgsatown, 27-29 JUly 1981, I ~ ~9. Publ Morgantown: West Virginia University, 1981
St~xlles to investigate floor heave at the Zelgler Coal Compax~ No. 5 a~l Murdock room a~i pillar mines were carried out. Floor heave phenomenon were found to occur where there was a combination of critical factors, ir~luling low urderclay cohesive streDgth, low claystone cohesive strength, low ratio Of u~ierclay to claystone cohesive strer4~th, thick underclay stratum, and high pill~r stresses. High natural water content was found to be an importar~ determinant of ur~erclay and claystone strengths.
831109 STRATA DIS~K~RBANCE PREDICTION FOR MINING ~E~EATH SURFACE WATER AND WA_~E IMPOUNDMENTS Simgh, M M; Kenicrski, F S Proc 1st Conference on Grou~i Control in Mining, Mcrgantcwn, 27-29 July 1981, F7689. P~bl Mc~gantown: West Virginla University, 1981 Modes of strata disturbance iniuced by uniergrourd mining are first discussed: surface s~bsiderite, sinkhole pher~x,er~, subsurface strata movement, char~es in permeability due to strata movement anl surface crack closure. The mechanics Of strata disturbance for mining beneath surface bodies of water are then considered. 831110 ENGINEERING ANALYSIS O F ' S Q U E ~ ' FAILURE OF PILLARS IN THE PITTSBURGH COAL ~ D Mishra, G; Grayson, R L Prom 1st Comfererm.e on Ground Control in M.l.ni~, Mcrtp~t;o~rn, 2'~.-29 J u l y 1981, 1,11~153. Publ Mcr@~ntc~n: West Virginia University, 1981 Presents a case study of the Nemaeolln coal mine, Pezmsylvanla, USA where rapid failure of pillars occurred due to squeeze. The develol~nent of the eq~eeze, its im~ogression in time ar~ analyses of 1:,he cor~Ition are described. The effect of further mlnimg is A~l~Vsed.