Strategic Minerals of New England ALONZO QUINN
Brown University, Providence, Rhode Island
A .
LTHOUGH bountifully endowed with many mineral resources, the United States has an insufficient supply of a number of minerals necessary for the successful prosecution of war. Those minerals which cannot readily be obtained in adequate quantity or quality from domestic sources are termed "strategic minerals." They constitute a wartime problem whose solution may be found in one or more of the following ways: (1) finding new deposits; (2) more efficient mining or milling of known low-grade ores; (3) subsidizing the working of low-grade deposits; (4) restriction of civilian use; ( 5 ) more efficient technology in the use of material; and (6) development of substitutes. All of these methods have been used during World War I1 in developing an eminently successful strategic minerals program. Even before the United States became involved in war, the United States Geological Survey and the United States Bureau of Mmes in cooperation with several State agencies instituted a vast program of findmg and developing new deposits of strategic minerals, The present paper briefly describes some of the methods of exploration used by these government agencies and by private business in the New England States. Four mineral substancescopper, manganese, tungsten, and mica-have been chosen to illustrate the methods of exploration, although several other minerals have been produced or sought in this area. The total output of New England has, of course, been small compared to that of the whole country and compared to other contributions the New England area has made toward winning the war.
ore, which will be reduced by the mill to about 50 to 60 tons of concentrate containing 25 to 30 per cent copper. MANGANESE
The rich oxide ores from Russia normally supply our steel industry with much of its needs of manganese. During this war, however, i t has been necessary to obtain most of our manganese from other foreign deposits and from the inadequate domestic deposits. Among the many small manganese deposits of this country is that a t Plainfield, Massachusetts, which consists of a mixture of carbonates (rhodocbrosite, MnCOa) and silicates (rhodonite, MnSiOs, tephroite Mn2Si04, etc.). The low tenor of this ore, reported to be about 20 per cent manganese,' makes it suitable only for certain purposes, such as a flux in the making of manganese pig iron, but the use of this material releases the higher grade ores for more exacting use. This deposit was also given a careful surface study by the Geological Survey and core drilled by the Bureau of Mines. Geophysical methods have been suggested as a means of discovering whether other similar deposits may be hidden by the thick mantle of glacial drift. The complicated geologic structure and the great variety of minerals make this an especially interesting deposit. The last production figures published give the following amounts as having been produced by the Tacouic Mine a t Plainfield, Massachusetts: 1938, 230 long tons; 1939, 649 long tons; 1940, 1900 long tons. 1941, 4000 long tons4,
COPPER
After a lapse of several years Vermont is once again producing copper from a group of chalcopyrite, (CnFeSz) deposits including the Ely lode in Vershire the Pike H i deposit of Corinth, and the Elizabeth mine of South StraBord. Present operations are a t the Elizabeth deposit which has been worked a t various times since its discovery in 1793. The current mining was undertaken after a detailed geological examination of surface exposures of the bedrock by the Geological Survey and a thorough program of core drilling by the Bureau of Mines.' On the basis of these resultsthe mine was opened and a mill constructed for the concentration of the ore. Production figures are not being published, but Jacobs2 has reported that plans for the mine indicate an expected daily output of 500 tons of U . S . BUREAUoa MINES, The Elisebeth Mine, Orange County, Vermont. War Minerals Report.No. 2. 1942. 'JACOBS, E . C., Reopening of the Vernronl Copper Mines, Report of the StateBeologist o f Vermont, 1941-1942, pp. 1-16.
TUNGSTEN
No tungsten is being produced in New England, but it is discussed here because of the unusual method of prospecting used unsuccessfully here and successfully in the western states. The chief tungsten ore mineral in China and Burma, the main producers, is wolframite, (FeMu)WOa, a heavy dark mineral which is very easy to detect by sight. The most abundant tungsten ore mineral in this country is scheelite, CaW04, which is very difficult to detect by sight because i t resembles its associated minerals. Fortunately, this difficulty is obviated by the fact that scheelite fluoresces. The resulting very easy method of prospecting has been used widely and successfully. Likely places are discovered by daytime
-
"Minerals Yearbook for 1941," U . S . Bureau o f Mines, 1943, p. 590. 4"Minerals Yearbook for 1941." U . S. Bureau of Mines, 1943, p. 588.
May, 1945 searches and then examined by night with a portable ultraviolet light (about 2537 angstroms). Not only does the scheelite glow brilliantly, but the color indicates whether it has the normal amount of tungsten (bluish fluorescence) or whether some of the tungsten is replaced by molybdenum (yellowish fluorescence). The vicinity of Tmmbull in Connecticut, Copper Mine Hill in Rhode Island, and a number of other places were found to have low-grade and small deposits of scheelite, but larger and richer deposits were found in California, Nevada, and Idaho. MICA
addition to the usual minerals, belyllium, boron, lithium, caesium, columbium, tantalum, and many other rare substances. A consequence of the origin of the pegmatite deposits is that they are commonly, although not always, irregular in shape and of small size. Much of the prospecting must be on a small scale. Many a New England hillside was prospected and considerable mica was recovered from small pits opened by farmers in their spare time. The wartime program of detailed study and mapping of many pegmatite deposits has revealed that the distribution of mica is much more systematic than had been supposed. Only the clear, sound mica with regular cleavage can be used for strategic purposes; much that is stained, frayed by weathering, or Which has inclusions of iron minerals is unsuitable. New testing @stmments have been developed in an effort to eliminate the guesswork from mica testing and this hasadded to the supply of usable mica. An interesting result of the testing of mica is the demonstration that, contrary to the previous opinion of many mica fabricators, the best domestic mica is equal to the India mica. The prejudice against domestic mica has resulted from the fact that cheap and skilled labor in India made i t practical to grade and prepare mica much better than had usually been done in this country. A consequence of the combined.program of prospecting for domestic deposits, encouraging the mining of mica in foreign countries more accessible than India, and the better testing of mica is that our needs have been met thus far, but mica has ranked as one of the most critical of our mineral needs throughout much of the war.
Mica has a most remarkable combination of properties which make it indispensable in wartime and which have not yet been duplicated by any other substance. It has unusually great electrical resistance, can withstand high temperature, is not affected by water or most acids, has a pronounced cleavage, is tough and elastic, is transparent, and can easily be cut or punched into desired shapes. The greatly expanded use of electrical equipment a t a time when our chief source, India, was threatened made i t imperative that we find other sources. New England had long produced a small amount of mica, so it was one of t h e areas prospected. The main commercial occurrence of mica is in pegmatite deposits. These are the result of crystallization of the last aqueous juices of a great body of granitic liquid a half-mile or deeper within the earth. These watery juices differ from ihe parent granite liquid by their ability to produce crystals so coarse that large sheets of mica may be recovered. The resulting pegmatite rock may consist almost entirely of feldspars, OTHER STRATEGIC MINERALS quartz, and micas, the same minerals as in granite, or Other strategic minerals produced or prospected for it may have concentrated within it many rare substances which had been widely dispersed in the granitic in New England include asbestos, beryllium, fluorite, liquid. The latter type of pegmatite may have, in iron, lead, molybdenum, and zinc.
Those interested in the interpretation of the "Servicemen's Readjustment Act of 1944," under which many returning veterans will some time be attending our schools and colleges, will find a digest and discussion by Charles K. Morse, of the Veterans Administration, in the Febmary 15 number of Htgher Education (published by the U. S. Office of Education). Another very comprehensive discussion of the same subject, with the results of several questionnaires and surveys made to determine the likely future course of events, is the subject of Bulletin No. 78, Higher Education and National Defense, Febmary 26, 1944, issued by the American Council on Education (744 Jackson Place, Washington, D. C.). 0 The Institute of Makers of Explosives is anxious to take some effective steps to point out the dangers involved in.attempts by youngpersons of high-school age
to compound explosive mixtures. This effort is prompted by the fact that serious accidents have occurred in the past as a result of the practice. The Institute wishes to ask teachers of chemistry for details of such accidents a v have come to their attention. It is desired to know primarily what measures to discourage the practice they have found to be most effective. It would also be helpful if they would describe the circumstances of any accidents, the extent of injuries, and the motives involved in attempting such experiments. After this information is collected and correlated it will be made available to teachers and to others interested, and necessary safety measures will be pointed out. Teachers are asked to send such information to the Editor of THIS.JOURNAL, whence it will be turned over to the Institute.
