Document 71yE15wnnBQp1n5DQBea77DX8

Jua* 14, 1961 Mr. C. A. Pratt, Vie* Priildiat WtUrs Mlurtl Product* Co. 472S 01*oo Manorial Highway Ml as* spoils 22* Minnesota Osar Cap: la rspiy to your Lttr of Jua* 12 I am happy jo ootlia* our past experience la regard to tho effect of dust la our alU upon oor employ***' health. This U a very eoapUs amd eoafueiag Ihiag *ad oao from which U la difficult to draw aey ceaclualoaa. I will outllao our history oa this la the hop** that it may bo of soaa help to you. As background to oar experience, you kaaw w* havo always had th* p?obl:.*a of dust la our milling aad handling of vermlealite. This problem has n celved coaaldarahlo atuatioa over tho years aad wo havo attempted to take whatever slope a*css*ary to eoolrol tho dust latoasity whoro there would bo aa exposure to employ***. W* have met with varylag degrees of success la various placoa la tho op* ratioa. Many stadia* havo hooa mad* of tho dust aad dual problem by dlffareat popla over tho year* la analysing tho problam. All stud Is* hav* showa that la :ko operation char* la ao tree silica prasuot, hot tho m&oorals fouad la ths doposl are silicatea, mica* aad asboetoe*llko mla*rale. SlUcaals Is cauoed by free silica aad aot by tho allleataa. Ashe*tea, however, Is a causo of aaboetoela, which has boea a mattar of concern. Thoro la a rolotivoly largo amount of asboatoa dost prosaot la our mill aad this is difficult to control. From a report written la 1954 by aa Industrial Hygiene Lagiaeer, Dlvuton of OleoAso Control, Motdaaa State Board of Health* ! quote the fallowing oa tho dust tosidtyt "A review of tho literature ladlcatoe that vermlcullta or tho dost from thie material le not especially toadc aad la generally included only as a nuisance dust. However, tho asbestos duet la the dust La the air Is of considerable toxicity, and Is a (actor U.tho consideration of reducing dustiness la this pleat." Mr. C. A. *ret Hsge Five Jum 14, 1941 These wilt not elimlnen the dust problem In the concentrates. but expect to eul It dm considerably. This hs boon i review of oar situation. 1 hope it will be of same help to you. Oar dust control problem receives continuing attention from our mill superintendent. U le one which we continually work on to trying to keep our ventilation no efficient oe poeeible end whenever It le possible to make any Improvements we try to do so. We usually receive a visit from on engineer from the State Board of Health about once a yeer end he usually mekee recommeadactone to us which we trv to carry out. !f there ie any further help that we caa give you* we will certainly be l*a to try to furnteh it. tf there are eay particular points on this dlecourse upon which 1 could olnborato further* please .feet free to ssk mo to do so. 'riacerely yours iCNOUTk* COMPANY By: S, CL Lovick Ow/jbr-- June 14, 1961 Mr. C. A. Prill, Vie# President Wteiers Mineral Products Co. 4723 Olson Memorial HigherOf Minneapolis 22* Minnesota Dear Cap: la reply to your letter of June 12 1 am happy Jo outline our past experience la regard to the effect of dust la our mill upon onr employees' health. This is a very complex and confusing thing and one from which U la difficult to draw acy conclusions. I will outline our history on this in the hopes that it may be of soma help to you. As background to our experience, you know wo have always had the problem of dust la oar milling and handling of vermlcallte. This problem has re calved considerable attention over the years and we have attempted to take whatever steps necessary to control the dust intensity where there would bo an exposure to employees. We have met with varying degrees of success la various places in the operation. Many studies have been made of the dust and dust problem by different people over the years ia analyzing the problem. All studies have shewn that In the operation thnre la no free silica present, hut the minerals found in the depest ore silicates, miens and asbestos-Ilka minarals. Slllcoals Is caused by free silica and not by the silicates. Asbestos, however, ia n causa of aebeaioeia, whieh has been a matter of concern. There is a relatively large amount of aaboatoe dost presnet la our mill and this Is difficult to control. From a report writtsa in 1956 by an Industrial Hygiene Lagtueer, Dlvtelou of Olaaase Control, Montana State Board of Health, I quote the fallowing on the dust toxicity: "A review of the literature indie a tee that vsrmtculSM or the dost from this material Is oot especially toxic and Is generally included only ns s nuisance dust. However, the asbestos duet la the dust la the air (a of considerable toxicity, end Is a factor la.:ha consideration of reduclog dust loess lathis plant." Mr. C. A. Prut Pegs Flv* J um 14, 1961 Thsss will aec slimtnak* th# dust problem in the concentrates, but we expect to cut It does considerably. This hat been a review of oar situation. 1 hope It wilt be of same help to you. Our dust control problem receives continuing attention from our mill superintendent. It is one which we continually work on in trying to keep our ventilation as efficient as possible and whenever it is possible to make any improvements we try to do so. We usually receive a visit from an engineer from the State Board of Health about once a year and he usually makes recommendations lo us which we trv to carry out. If there is any further help that we can give you, wo will certainly bo jiao to try to furnieb it. U there are any particular points on this discourse upon which 1 could elaborato further, please .feel free to ask me to do so. Sincerely yours Z CNOU7 K COMPANY By: K. D. Lovick t Du/jbr--