Newport daily independent., 1905-08-28
MOLYBDENITE MINE.
ORE USED IN MANUFACTURE OF
 STEEL FOUND IN MAINE.
Deposits Are of Rare Occurrence and the Value of Those Located
 Is Partly Conjec-
 tJlral

One of the principal deposits of molybdenum ore in this country Is at Cooper, Me It was visited in Sep tember. 1904, by Dr. George Otis Smith, of the United States geological survey, who tells in bulletin 26o. the surveys annual publication on US ex- ploits in economic geology. how the American Molybdenum company pre- vented him from having more to say about the molybdenum of this locality. He was not permitted to visit the mine. but the observations he made at the surface furnished him sufficient data for a consideration of the character and origin of the deposit.
 The town of Cooper Is in Washing ton county, in the extreme southeastern part of Maine, and is the fourth town- ship west of Calais. The nearest rail- road station is Marion, in the second township south, Prospecting for mo- lybdenits has been carried on at sev- eral points in this locality, but the only important development thus far is that on the property of the American MO lybdenum company.
 The molybdenite occurs both In peg matite dykes and in the granite cut by these dykes. A number of distinct peg matite dykes were seen on this property. varying in width from few inches to several feet. In these the molybdenite occurs in lead-gray hexagonal crystals of short prismatic habit, or as less reg ular foiiated masses. often with radiats structure. The molybdenite is found also in small flakes or larger nests or flakes disseminated throughout the granite mass.
 Molybdenite occurs at several other localities in Maine, as we'll as ln tho other. New England states. It Is usu- ally found in small flakes disseminated through tho granite or gneiss. so that the Cooper occurrence IS of speclal interest by reason of the light 1t throws on the origin of this mineral. The pegmatite dykes are probably approximately contemporaneous with the granite intrusion, representing the latest specialization of the gran itic magma, and therefore intruding the consolidated granite. In this pegmatite magma molybdenum disul- phide appears to have been a promi- nent constituent and to have crystal lized early in tho consolidation of the dykes. Tho molybdenite in the gran ito may be either the result of impreg- nation at the time of the pegmatitic intrusion or it may be an original con stituent. The former view is support ed by the apparently larger amount in the granite near the dykes.
 The ores of molybdenum have been in greater demand since molybdenum has been used in the manufacture of steel to increase it's hardness and toughness. The comparative rarity and high cost of the ores, have, however, limited its use.
 The economic value of such deposit as the Cooper molybdenite is partly con jectural. The conditions for quarrying and mining both the pegmatite and the wall rock appear favorable, and con- siderable work of this kind has been done. The rock lying on the dump contained varying proportions of mo- lyudenite, but it seemed that most of the crude ore could be readily distin- guished and separated from the barren rock by hand picking. The crucial test of the successful working of such . de- posit is doubtless connected with the milling process. 'rGtter than with tho mining methods. A compact plant for treating the molybdenite ore has been erected by this company, but the de- tails as to cost of crushing the rock and of concentrating and cleansing the sep arated mineral could not be ascertained