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Bord And Pillar Mining Method Pdf Download

 
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MessagePosté le: Ven 2 Sep - 06:39 (2016)    Sujet du message: Bord And Pillar Mining Method Pdf Download Répondre en citant




Bord And Pillar Mining Method Pdf Download > bit.ly/2bOwPvR







Bord And Pillar Mining Method Pdf Download

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Retreat,mining,is,a,particularly,dangerous,form,of,mining:,according,to,the,Mine,Safety,and,Health,Administration,(MSHA),,pillar,recovery,mining,has,been,historically,responsible,for,25%,of,American,coal,mining,deaths,caused,by,failures,of,the,roof,or,walls,,even,though,it,represents,only,10%,of,the,coal,mining,industry.[5].,Room,,,and,,,pillar,,,mines,,,are,,,developed,,,on,,,a,,,grid,,,basis,,,except,,,where,,,geological,,,features,,,such,,,as,,,faults,,,require,,,the,,,regular,,,pattern,,,to,,,be,,,modified.,,,403,Forbidden..,To,,prevent,,this,,the,,mine,,is,,divided,,up,,into,,areas,,or,,panels.[2],,Pillars,,known,,as,,barrier,,pillars,,separate,,the,,panels.,,Hustrulid,,,,William,,,A.;,,,Bullock,,,,Richard,,,L.,,,O.,

If,the,pillars,are,too,small,the,mine,will,collapse,,but,if,they,are,too,large,then,significant,quantities,of,valuable,material,will,be,left,behind,,reducing,the,profitability,of,the,mine.[2],The,percentage,of,material,mined,varies,depending,on,many,factors,,including,the,material,mined,,height,of,the,pillar,,and,roof,conditions;,typical,values,are:,stone,and,aggregates,75,percent,,coal,60,percent,,and,potash,50,percent.[2].,Early,,room,,and,,pillar,,mines,,were,,developed,,more,,or,,less,,at,,random,,,with,,pillar,,sizes,,determined,,empirically,,and,,headings,,driven,,in,,whichever,,direction,,was,,convenient.[3].,,Room,,,and,,,pillar,,,(variant,,,of,,,breast,,,stoping),,,,also,,,called,,,pillar,,,and,,,stall,[1],,,is,,,a,,,mining,,,system,,,in,,,which,,,the,,,mined,,,material,,,is,,,extracted,,,across,,,a,,,horizontal,,,plane,,,,creating,,,horizontal,,,arrays,,,of,,,rooms,,,and,,,pillars.,,,After,,,the,,,pillars,,,are,,,removed,,,,the,,,roof,,,(or,,,back),,,is,,,allowed,,,to,,,collapse,,,behind,,,the,,,mining,,,area.,,,Once,started,,such,chain,reactions,can,be,extremely,difficult,to,stop,,even,if,they,spread,slowly.[4].,Room,,and,,pillar,,mining,,is,,one,,of,,the,,oldest,,mining,,methods.,,Longwall,mining,.,Notes.,,

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