<*F!T?T6F q; ,*%, C, s Technology News ,, YIU- ,+ From the Bureau of Mines, United States Department of the Interior 

-'e& $*\+ Technology new$ dmribos lewd developments 1mm kmau of Mines vogrpma. It ie publish4 to onmutqe the 

rransfsr ofthis informarlon to tho mineral6 rndustfyand its application in wmmercial pradiw. Msntion of mrnpany 

or product names is for documntation only and does nM imply sndorsmnt of a speciir: lirm or product. 

Bursau d Mines research t~ prforrned and reprtd under mandata of tha United Stat- Congress. For 1 tn 

wb.crlpam to Te~hnohgy Newa, write to Mes of Technology Transiu, Bureau of Mine8, MS 6201, 

610 llh Sf NW, Washington, DC 20211 -0001. 

No. 430, Marclz 1994 

Translucent Face Partition Reduces 

Longwall Workers' Dust Exposure 

Objective application. The meshes tested had 6.35-mm (l/&in), 

3.13-mm (l/8-in), and 1.59-mm (1116-in) opening sizcs, 

exhibiting open arcas of 83.7, 52.5, and 30.0 pct, rcCrcatc two air splits along the longwatl lace to isolate spcctivcly. Each mesh size was evaluated to separate a the shcarcr-generated dust to the immediate face arca, 152,4.m-long (500-ft-long) entry into two parallel splits maintaining a clcancr split oC air in he wurkers' walkway. Both bascline (no mesh) and mesh tests were 

conductcd over a range of typical air velocilies (1.02- 

Approach 4.06 m/s [200-800 ftjmin]) used at longwaIIs. DUSL was 

released on one side of the entry, and dust sampling was 

previous U,S, B~~~~~ ~i~~~ (USEM) studies have conduclcd alung 30.5-m (100-ft) intervals on both sides or 

shown tha~ an cxtcndcd facc-conveyor spillplale barrier Ih" ""''Yh 

can create two air splits effectively, but il pruwd to be Rc"lts showed that effective air splitting can be 

impractical because the workers could not see Chc fact achieved with the 3.18-mm (1/8-in) and 1.59-mm (I/r6-in) 

area and a reliable radio control was not yet mesh opening sizes. Notable dust reductions wcrc measavailable for (he shearing machines. ~h~ usg~'~ current ured un the one side of the cntry opposite thc dust fccd 

approach to air of using a polycstcr mesh source With lhe mesh partition. Average dust reductions 

partition to overcome the visibiljiy pr&lems uf a solid at 30.5 ('00 and 71+0 (2m '1) of the 

barrier, A pcrmeahle parliliun is L.xpcctcd to pro. SOU~CC for thc various air vclocitics wcrc 58 and 36 pct, 

vide adequate air-splil[ing capabililies as long as the prcs- rcs~ec'ivel~, for lhe 3.lRmm (1/8-in) mesh, and 79 

sure djffcrentjal belween the race and worker walkway ic "d 555 pet* rcs~ectivcl~~ for ihc 1.59-mm (l/lfi-in) mesh. 

minimal, New,reliable,radiorcrnotcshcarcr-controltcch- At th" higher air vcl@cilies (3-05 m/h and 4.06 m/s 

nology supplemenled 1hc devc]opmcnt of [his air-splitting IMO and rl/minl), difrercnccs wcrc 

technology. observed between the 3.18-mm (1/8-in) and 1.59-mm 

(1/16-in) mesh sizes. 

Laboratory Test Results Underground Test Results 

Experiments at thc USBM's Lakc Lynn Laboratory 

ncar Fairchance, PA, wcrc conductcd to dctcrminc thc Underground testing of the mesh partition was confeasibility of maintaining two parallel splits of air with ductcd at a longwall operation to verify its cffcctiveness as 

several difltrcnt S~ZCS of a pcrmcablc polycstcr mcsh a control technique. A cooperalive effort was conducled 

and to sclecl an optimum mcsh S~ZC for underground with thc mine to incorporate the mesh intn ils operalion. 

Thir documerlt was preparrd by tllc nurcau nf M~ncr Seithcr Ihe Unitcd Statcs Ciovcrnment nor anypcmn acting on bchalf of thc Unitcd Statcs 

Gouernment assume ally liability resulting from the urc of thc infonnatjon contained in this docurncnt, or warrants that such use bc lrcc from privately 

owncd nghts.