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Mining Publication: Preventing Falls of Ground in Coal Mines With Exceptionally Low-Strength Roof: Two Case Studies

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August 2004

Image of publication Preventing Falls of Ground in Coal Mines With Exceptionally Low-Strength Roof: Two Case Studies

Mines with exceptionally low-strength roof (UCS <3,500 psi="" and="" cmrr=""><40) are="" much="" more="" likely="" to="" struggle="" with="" roof="" falls="" than="" other="" mines.="" weak="" roof="" is="" a="" particular="" problem="" for="" many="" room="" and="" pillar="" mines="" in="" the="" midwestern="" and="" northern="" appalachian="" coal="" basins.="" traditional="" roof="" support="" techniques="" are="" often="" not="" up="" to="" the="" challenge="" at="" these="" operations.="" this="" paper="" focuses="" on="" two="" mines,="" one="" operating="" in="" the="" upper="" freeport="" seam="" and="" the="" other="" in="" the="" herrin="" no.="" 6="" seam.="" together,="" the="" two="" mines="" had="" more="" than="" 300="" roof="" falls="" during="" a="" recent="" 5="" year="" period.="" each="" has="" experimented="" with="" a="" variety="" of="" roof="" bolt="" types="" and="" lengths,="" and="" with="" different="" supplemental="" supports.="" detailed="" statistical="" analysis="" was="" conducted="" to="" determine="" which="" support="" combinations="" have="" proven="" to="" be="" most="" effective.="" geology,="" horizontal="" stress,="" and="" time="" are="" also="" important="" at="" both="" mines.="" successful="" control="" techniques="" have="" included:="" identifying="" particularly="" troublesome="" lithologic="" roof="" units;="" installing="" longer="" and="" stronger="" roof="" bolts;="" installing="" supplemental="" support="" in="" intersections,="" and;="" limiting="" the="" duration="" that="" a="" panel="" remains="" open.="" the="" lessons="" learned="" from="" these="" mines,="" and="" others="" like="" them,="" could="" help="" improve="" ground="" control="" safety="" for="" the="" entire="" u.s.="" mining="" industry.="">

Authors: C Mark, GM Molinda, LM Burke

Conference PaperAugust - 2004

  • Adobe Acrobat - Portable Document Format (.PDF)

    0.18 MB

NIOSHTIC2 Number: 20025354

Proc 23rd Intl Conf on Ground Control in Mining, Morgantown, West Virginia, Peng SS, Mark C, Finfinger GL, Tadolini SC, Heasley KA, Khair AW, eds. August 3-5, 2004. West Virginia University, 2004 Aug; :220-227

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