From Abstract: "This report describes the occurrence of the mica and its physical properties among which is an unusually wide range of colors. A table is presented showing the results of power-factor measurements made by the National Bureau of Standards on 196 samples of sheet mica from 109 mica mines and 15 feldspar mines.It is concluded that more systematic planning of mica mining, for the district as a whole. would result in an average yearly production of at least 90,000 pounds of relatively clear sheet and possibly much more."

Report issued by the U.S. Bureau of Mines on the progress made in metal-mine stemming. Previous reports have been presented impartially, or under different procedures. This report contains updated progress results from current procedures and mine conditions. The report includes tables, and illustrations.

Report issued by the U.S. Bureau of Mines over the ongoing issue of heaving-shale in the Gulf Coast area. The operations and potential causes of incompetent heaving-shale are listed. This report includes tables, and a map.

Report issued by the U.S. Bureau of Mines on the differing conditions of oxygen in explosives. Results from explosives samples with oxygen variations are presented. This report includes tables.

Report issued by the U.S. Bureau of Mines on investigations conducted on manganese ore used for smelting. Experimental methods and results are presented. This report includes tables, and a photograph.

Report issued by the U.S. Bureau of Mines regarding laboratory tests conducted on acid leaching of manganese ore. Descriptions of the methods used in testing and results are presented. This report contains tables, and graphs.

Report issued by the U.S. Bureau of Mines on testing of sub-audible noises and accuracy of rock burst predictions. The history of this study, and the results of these investigations are presented. This report includes tables, graphs, illustrations, and diagrams.

Report issued by the U.S. Bureau of Mines on sub-bituminous slack from Denver, Colorado. The characteristics and properties of 2-1/2 inch slack samples are listed. This report includes tables, graphs, maps, illustrations, and photographs.

Report issued by the U.S. Bureau of Mines on the annual work conducted by the Mining Division during 1942. Descriptions of projects and operations during the fiscal year are listed. This report contains tables, and photographs.

Report issued by the U.S. Bureau of Mines on the annual report of work conducted by the Explosives Division during the fiscal year of 1942. Descriptions of testing projects and operations are presented. This report includes tables, graphs, illustrations, and photographs.

Report issued by the Bureau of Mines over the operations of the Nonmetals Division during 1942. The work done by the division is discussed. This report includes tables, illustrations, and photographs.

From abstract: The Carrizo Mountains vanadium district is in the Navajo Indian Reservation, northeastern Arizona and northwestern New Mexico. From May through October, 1942, two mining companies, operating under lease agreements with the Navajo Service, opened several mines in the district and produced a total of about 6,000 tons of ore, averaging approximately 2.2 percent.

Abstract: In the accompanying report reference is made to all of the deposits in Alaska in which molybdenum minerals have been definitely recognized and reported. None of the deposits have been mined commercially, and none of them have been prospected thoroughly enough to afford quantitative estimates as to their tenor and potential reserves ; in fact, at only a few of the localities has there been more than surficial testing. Forty-one separate and distinct localities where molybdenum minerals occur are listed, and the available information on factors of geologic significance regarding each occurrence is given. A small-scale map of Alaska on which the various localities are indicated forms part of the bulletin, and in the text are extensive references to the various published reports and records of the Survey upon which the statements are based. In spite of the widespread distribution of molybdenum mineralization in Alaska, the remoteness of many of the localities, their handicap through dearth of transportation facilities and labor supplies, and the already wellsupplied condition of the American market for molybdenum ores discourage the early development of any of the known deposits or search for them in unsurveyed areas. These draw-backs will doubtless become -less important factors …

This report is part of a series describing the structural features, the character of the oil- and gas-producing beds, and the localities where additional oil and gas may be found in parts of Osage County, Oklahoma. This part provides an overview of the discussions in the previous 10 publications and provides a summary of relevant information.

From abstract: Tin-bearing veinlets are exposed in a small area near Izenhood Ranch, 22 miles north of Battle Mountain, Nev. They occur in thick rhyolitic flows of Miocene (?) age, and wood tin, found in the gravels of arroyos that head in the surrounding rhyolite, presumably comes from -other veinlets not yet discovered. The exposed veinlets are about 20 feet in maximum length and a quarter of an inch in average thickness. Parallel and reticulating veinlets form lodes 4 to 6 feet thick and 15 or 20 feet long. Virtually no cassiterite is disseminated in the wall rock.

From abstract: Mica has been mined in New Hampshire since 1803. Production from 1908 through 1939 has aggregated 13,326,990 pounds of sheet and punch mica, an annual average of 416,470 pounds. Since 1931 production has been below this average, because of economic conditions rather than depletions. The mica-bearing pegmatites of the Grafton and Keene districts occur mostly in sillimanite-mica schist adjacent to large areas of biotite gneiss. The pegmatite bodies range from a fraction of an inch to more than 200 feet in thickness; most of them are crosscutting, and about 75 percent strike northeast. Mica occurs sporadically in most of them but where present in commercial quantities it is localized in one or more of the following zones: (1) In quartz-plagioclase-muscovite zones 2 to 10 feet from the walls of large pegmatite bodies, (2) in or near quartz masses that occur mostly near the centers of the bodies, (3) in thin dikes 5 to 15 feet thick or in similar offshoots from larger bodies, (4) within large pegmatite bodies, in more or less tabular streaks or zones composed principally of plagioclase, quartz, and muscovite.

Technical report. Three extractions of a diethyl ether solution of uranyl nitrate with small portions of water are effective in removing rare earths, as is shown by radio-gadolinium and radio-europium tracer experiments. A study of representative ethers, alcohols, ketones, and esters showed that diethyl ether and a mixture of 85% ethyl methyl ketone with 15% xylene are the best solvents for the extraction.

Pressure drop calculations are shown for He cooled power plants ranging from 400,000 kw to 30,000 kw.

Preface: The author of this paper gives a thorough description of a complex of very unusual igneous rocks and associated hydrothermal deposits.

This report follows a study that deals with a portion of the ternary diagram previously analyzed, namely the boundary curves which separate the central area of two coexistent liquid phases from the two border stripe representing one-phase liquid systems.

Abstract: The manganese deposits of the Paymaster district, in Imperial County, Calif., extend along steeply inclined normal fault fissures which cut Tertiary (?) volcanic breccia and fanglomerate. The ore deposits are in part open-space fillings composed largely of psilomelane, and in part fault breccia replaced by psilomelane, pyrolusite, and manganite. Calcite and rock fragments are the chief impurities. High-grade ore now exposed averages about 40 percent manganese, and contains much barium. About 3,000 tons of ore averaging 42 percent manganese was produced from the district by hand-sorting in 1917-18. It is estimated that nearly the same amount could be produced again, largely from present workings. In addition, a few tens of thousands of tons of milling ore, estimated to contain between 10 and 30 percent of manganese, are believed to exist in veins one to three feet wide within one or two hundred feet of the surface.

From abstract: On the west coast of Chichagof Island, southeastern Alaska, are three nickel-copper deposits that consist of norite containing the sulfide minerals pyrrhotite, pentlandite, and chalcopyrite. The deposits are within less than a mile of each other and are, by water, 160 miles southwest of Juneau and 70 miles northwest of Sitka. The norite is part of a stock, about 5 square miles of which is above sea level. Other rocks of the stock are amphibolite, amphibolitic norite, gabbro, diorite, quartz diorite, monzonite, granite, pegmatites, quartz veins, and schist inclusions. The stock is intrusive into a Lower Cretaceous (?) graywacke formation and an Upper Triassic (?) greenstone formation, both of which are now metamorphosed to schist.

From abstract: Cassiterite and spodumene, of possible economic importance, occur in a belt, 24.5 miles long and 1.8 miles in maximum width, extending southwestward from Lincolnton to Grover, N. C. This belt is in the Piedmont province, an upland with an average altitude of 1,000 feet, and is readily accessible by rail and highway. The region is underlain by crystalline limestone, quartzite, schists, gneisses, and granite. The rocks strike northeast and, in most of the belt, dip steeply northwest. Most of them are deeply weathered.

From abstract: Cassiterite was discovered along Irish Creek in the Blue Ridge in the northern part of Rockbridge County, Va., in 1846, but active prospecting and development work were not begun until 1884. The production has been small, probably less than 1,000 tons of ore, and has come chiefly from workings on Panther Run, a small tributary near the headwaters of Irish Creek.