Document bB04r16y3380bk2v1GX9MRLmy

FILE NAME: Railroads (RR) DATE: 1959 July DOC#: RR073 DOCUMENT DESCRIPTION: MT Bureau of Mines Progress Report Gologie Investigations in the Kootenai-Flathead Area, NW, MT STATE OP MONTANA BUREAU OF MINES AND GEOLOGY B* G. Koch, Director BULLETIN 12 PROGRESS REPORT ON geologic investigations IN THE KOOTENAI-FLATHEAD AREA, NORTHWEST MONTANA 1. WESTERN LINCOLN COUNTY By Willis M. Johns .xnxs mxiietin has been prepared bv u n L r ntana Bureau of &PGeology t:he ,G?rreLattCNSoPr^thetrinveRailwiy Comnwaintvh and the Pacific Fewer * LigJt Company MONTANA SCHOOL OF MINES Butte, Montana July 1959 of t h i A f o Z 6 TM s .con?truoted to bring water from upriver. Section, t L \ ^ L f n : ; e ! ^ : t ^ : i s ? f 0? 1 1?eT L ^ f ^ t i ro n 1 ie 11 s ^ r 0^ . : ^ confined to the lower bench. > % ? .,^ s s v ^ ite?och S ^ v e l > although placering was No records of production are available. o m n a naice P la c e r Creek J S operations in the Libby area. now remains. 2^ No evidence of plaoeriSg iS the " Sinitv s -uu vicinity NONMETALLIC DEPOSITS Vermiculite , T^e lafgst vermiculite mine in. the United States has been dr + h Pef hl Zonolite Company in the Rainy Creek district 7 miles northeast of Libby. The deposit was discovered in 1915, and small- soale production started in 19 25. In 1939, the several different perations were combined into one under the Universal Zonolite and oaSv pany iini1 l?S9 l4o8.mPAAni1,*0n0o0i-J\tnoanmemil?l?, Wheircehctweads incha19n4S8e,d to the Zonolite produced 'KO to per day, and it is presently'being enlarged Although the company has an expanding plant in Libby, the bulk of concentrate is shipped as crude vermiculite to expanding plants C4.o0m0 the Zcnoi??e!y - ^ 6Xpanded vermiculite is marketed under the The deposit is an elongated stock composed of pyroxenite and syenite. The stock intrudes strata of both the Wallace and Striped Peak formations m the trough of a northwest-trending syncline The pyroxenite is very coarse-grained and composed of vermiculite, aegerme-augite, soft fibrous amphibole asbestos (tremolite), mag netite, and locally a little biotite. Fluorine-rich apatite makes ^ u ,f the r o c k * The vermiculite has been derived from biotite by hydrothermal alteration, and locally, the quality of the vermiculite probably has been enhanced by weathering. The fibrous amphibole is an alteration product of the aegerine-augite, and the : stages of alteration can be seen megascopically in hand specimens The aegerine-augite is locally vanadiferous (Pardee and Larsen/ j iy^y, p* i7/* . . j The pyroxenite is cut by syenite dikes ranging in width from -I a few inches to many tens of feet. -The dikes are composed of ortho- " clase, sodic plagioclase, and a little muscovite. Accessory minerals are hornblende, fluorite, apatite, titanite/ rutile; biotite, and i garnet (Pardee and Larsen, 19 29 , p. 21). - - 38 - _ fiuartz veins in'the stock'are later than the syenite and contain small amounts of chalcopyrite, sphalerite, and galena. This unusual stock-has many minerals of potential value The vermxculxte, of course;, is being -actively marketed at present. Fxbrous amphxbole asbestos, because its specific gravity is very near that of vermxculite, causes much trouble in milling the lower grade ores in which the asbestos is abundant. If a process Ckld+b e "perfected^' to make a clean separation of Vermiculite and asbestos, both products would be marketable, and much material now mxned and dumped as waste could be milled and made to yield a profit. Much the syenite is nearly pure feldspar. Dikes which occur within the pyroxenite ore-body must be mined along with the vermxculite rock. At present the syenite is dumped as waste. It is said that minute inclusions of hornblende in the feldspar render the feldspar unsuitable-for ceramic_use. Perhaps it could be used as a flux in glass manufacture, or ground to a scouring powder of the Bon Ami class. (The basic ingredient of such powders is ground feldspar.) The border phase of the pyroxenxte intrusive where it conies xn contact wxth Belt sediments is magnetite-rich. A grab sample of the material showed about 16 percent magnetite. An analysis of a magnetic concentrate from .this material gave 6 3 . 8 0 percent iron 0.60 percent titanium dioxide, 2 . 4 0 percent silica, and 0 50 per-* cent phosphorusj also, a trace of sulfur. The high phosphorus was probably due to the presence of fluorapatite in the pyroxenite. . The quartz veins of the pyroxenite area, according to Pardee and Larsen (1929, p. 27), contain a variety of minerals, chiefly quartz with scattered grains of galena and chalcopyrite. Along the walls of one vein are zones a few inches wide made .up chiefly of vanadium-bearing aegirite, microcline, strontianite, celestite pyrxte, and chalcopyrite, with smaller amounts of quartz, fluorite, and sphalerite. Quartz veins are ignored in mining vermi culite as they are of mineralogical interest only. Esther May Asbestos . .The Esther May claims were staked by Romeo and Virginia Garrison in 1946 and are about one-half mile west of Yaak, in sec. N *J R * The .group comprises two unpatented claims, the Esther May Nos. 1 and 2. In 1948 the claims were leased to -Messrs. Hough and Loveland of Spokane, Washington, for a period of ten years. The lessees drilled twelve to fifteen holes near a small asbestos vein outcropping on a bluff. All holes were reported to have intercepted amphibole asbestos at depths of twenty to thirty feet. In 1958, Messrs. H. P. Reinshagen, Sr. and Jr., of Libby Montana, leased, with option to buy, the property for a period of one year. A diamond drill program is planned to check previous churn drill results. 39