采矿工程翻译.docx

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1、Inthiscasethecoalseamwas5.25-6.23ft(1.6-1.9m)thick.Theframesupportswith45tonssettingloadand70tonsyieldloadwereemployed.Theimmediateroofwasweakandunstableclayshale.Itfellsofrequentlythatthesupportlegswereburiedmostthetime.Thisresultedinslowfaceadvanceandconsequen

2、tlylowproduction.Thestantisticalroofobservationmethodwasemployedtoidentifythecausesandtorecommendimprovements.Duringobservations,thefacewasdividedinto20sections.Theobservationsconsistedofthreeperiods,eachlastedfortwotothreeweeks.Theresultsaresummarizedintable4.6

3、.2.Analysisoftheresultsobtainedinthefirstperiodidentifiedthecauseoftheroofcontrolproblems:theimmediateroofabovethesupportshadbeenseverelybroken.Thiscausedthesupportresistancetodroptheloseeffectiveness.Thefallenrockdebristhatburiedthesupportlegsseverelydelayedthe

4、operationofsupportadvance.Inordertoimprovetheconditions,1.2-in.(30-mm)thickwoodboardsandwiremeshwerelaidonthetopofthecanopyasasupplementingroofcontrolmeasure.Inthesecondperiodafterimplementationofthesupplementarymeasure,theroofconditionsimprovedconsiderably.Asam

5、atteroffact,everyitemintable4.6.2handimprovedexceptthatthenumberofroofstepsincreasedfromthreetofive,buttheaverageheightsofthestepdroppedfrom6.69in.(17cm)to3.93in.(10cm).duringthethirdperiodtheimprovedconditionspersisted.Thusitwasconcludedthatwoodboardsandwiremes

6、hshouldbeincorporatedaspartoftheroofcontrolplan.