Report issued by the Bureau of Mines regarding studies conducted on zinc-lead mines in Clark County, Nevada. Physical qualities of the mine, equipment used, and methods of sampling are presented. This report includes tables, and maps.

Report issued by the U.S. Bureau of Mines regarding specific manganese ore from Nevada and its use in electrolytic production. The development processes and methods are presented. This report includes tables, maps, illustrations, and photographs.

Report issued by the U.S. Bureau of Mines on energy consumption in the western United States. A focus on coal as the primary energy source is presented. This report includes tables, graphs, maps, and illustrations.

Report issued by the U.S. Bureau of Mines on the exploration of the Mount Hope mine. Analysis of samples obtained from core-drilling are listed. This report includes tables, maps, and illustrations.

From Introduction: "This publication is a summary of earthquake activity in the United States and the regions under its jurisdiction for the calendar year 1939. A history of the more important shocks of the country appears in Serial 609 of the Bureau, "Earthquake History of the United States: Part I-"Continental United States (Exclusive of California and Western Nevada) and Alaska," and Part II. -"Stronger Earthquakes of California and Western Nevada, Revised (1941) edition."

Report discussing earthquake activity in the United States during 1940. The report is broken down by regions and has sections for specific earthquakes.

Report discussing earthquake activity in the United States during 1941. The report is broken down by regions and has sections for specific earthquakes.

Report discussing earthquake activity in the United States during 1943. The report is broken down by regions and has sections for specific earthquakes.

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.

Abstract: This report summarizes the results of reconnaissance study of quicksilver deposits in the northwestern corner of Nevada, the northeastern corner of California, and Lake County, Oreg. made in August 1940. The Lene Pine district, Nevada, the Silvertown and Red Hawk properties in California, and the Currier and Glass Butte properties in Oregon were included. The first two of these require further development before a definite opinion as to their value can be formed. The Red Hawk mine has yielded high-grade ore, but the ore bodies so far worked are very small and scattered. The small amount of development at the recently opened Currier mine has yielded encouraging results. The deposits in the Glass Buttes are large but of such low grade that thorough sampling would be needed to determine their value. In general the region appears to warrant more attention from quicksilver prospectors than it has yet received.

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

Abstract: The Three Kids manganese district, in Clark County, Nev., has produced between 15,000 and 20,000 tons of ore, which contained between 30 and 40 percent manganese, 1.5 percent iron, and 12 percent silica. It is estimated that the reserves in the district aggregate about 5,500,000 tons of ore averaging about 10 percent manganese. Of this amount about 800,000 tons contains more than 20 percent manganese and 4,700,000 tons contains from 5 to 20 percent manganese. The manganese ore is a sedimentary deposit and consists of wad interbedded with lake or playa sediments belonging to the Muddy Creek formation of Pliocene (?) age. Where the manganese content is as high as 30 percent, the wad forms thick massive beds separated by thin almost barren partings. Where the content is low, the wad forms very thin lenses or small irregular blebs scattered through sandstone, or a cement for the sand grains. The zone of manganiferous beds ranges from about 10 to 75 feet in aggregate thickness, but at most places the thickness is between 25 and 40 feet.

Abstract: The tungsten deposits of the Nightingale district are just within the western border of Pershing County, Nev., and in the Nightingale or Truckee Range, which lies east of Winnemucca Lake. The Tertiary volcanic rocks of the district rest unconformably upon intrusive granodiorite and steeply dipping metamorphosed limestones and slates of unknown age. The tungsten deposits are of the contact-metamorphic type: The ore consists of scheelite bearing tactite, a dark silicate rock that was formed by metamorphism of limestone at the granodiorite contact. Scheelite (calcium tungstate) is the only valuable mineral. The gangue minerals are epidote, quartz, pyroxene, garnet, calcite, tremolite, molybdenite, pyrite, pyrrhotite, chalcopyrite, arsenopyrite, apatite, and sphene. The bodies of tactite are generally tabular, and they extend downward steeply, because both the limestones and the granodiorite contact dip vertically or nearly so. The largest tactite body of the district is at the Nightingale mine; it attains a maximum thickness of 60 feet and is nearly a thousand feet long, but only for part of its length is it thick enough and rich enough to be potentially minable. That it continues downward below the mine workings, which extend to a depth of 128 feet, is shown by nine drill …

From introduction: The object of this paper is to describe the salient features of Jurassic diastrophism in parts of the Tonopah and Hawthorne quadrangles in west-central Nevada. The problem is complicated by the lack of continuity of exposures, earlier folding of the older rocks, metamorphism caused by the later granitic in-trusions, and by superposed Tertiary and later normal faults.

Report describing the characteristics of manganese deposits found in White Pine County, Nevada, and geographic information about the surrounding area.

Abstract: The presence of cinnabar in the Wild Horse district, in western Lander County, Nev., has been known since about 1916, but little ore was produced until 1940. In that year and early in 1941, deposits discovered in 1939 were mined to apparent exhaustion by the Wild Horse Quicksilver Mining Co., which had produced 827 flasks at the end of April 1941. The district is underlain by moderately deformed sandstone, shale, and limestone of Lower and Middle Triassic age, locally covered by remnants of a mantle of Tertiary fanglomerate, tuff, and lava. The Triassic rocks are partly silicified, and cinnabar has been found in and near silicified rock, particularly the silicified limestone at the base of -the Middle Triassic. The ore bodies so far discovered were individually small and ill-defined, and had an average tenor of less than 0.5 percent of quicksilver. Other similar ore bodies are to be expected at moderate depths, but the cost of exploration for them may, perhaps, prove excessive.

From Introduction: "The Opalite quicksilver district includes two deposits with a considerable past production, one deposit with a small production, and one unproved prospect. These deposits are located along the circumference of a semicircular area that extends from a short distance west of McDermitt, Nev., for about 20 miles along the Oregon-Nevada State boundary. (See fig. 34). The area thus includes parts of Humboldt County, Nev., and Malheur County, Oreg.; almost the entire production has been derived from the portion in Oregon."

Abstract: The tin and copper deposits at Majuba Hill, Pershing County, Nevada are in a partly brecciated plug of Tertiary rhyolite porphyry, which is altered nearly everywhere to quartz and sericite and in some places is intensely tourmalinized. The tin mineral, cassiterite, appears to be associated with the alteration, for the single concentration of it was formed by replacement of altered breccia. Brecciated and altered rock is, however, only a general guide to potentially tin-bearing ground, and not a specific guide to ore shoots, for most of such rock appears to contain only small amounts of cassiterite, widely and unevenly distributed. The known deposit, which is exposed only underground, is at most 20 by 20 by 10 feet in size, and may contain about 12,000 pounds of metallic tin. The deposit is cut off by a normal fault, which apparently is of small displacement, and the footwall segment has not been found. The copper deposit is in the same normal fault, about 300 feet south of the earlier-formed tin deposit. From it about 4,000 tons of 12 percent copper ore was mined in 1915-18, but none has been mined since and no copper ore is now in sight.

A report regarding pegmatites of the Errington-Theil mine, Elko County, Nevada.

From Introduction: "This report records a chapter in the history of the development of an electrolytic manganese industry in the United States."

Technical paper issued by the Bureau of Mines over investigations of available coal in Esmeralda County, Nevada. Exploration of the coal deposits is discussed. This paper includes tables, maps, photographs, and illustrations.

Technical paper issued by the Bureau of Mines over analyses of coals from many western states. The characteristics of the coals found in each state are discussed in detail. This paper includes tables, and maps.

Report issued by the U.S. Bureau of Mines discussing safety hazards in western mines. Mine hoisting and haulage accidents are presented. Accident prevention is also discussed. This report includes tables.

Report issued by the U.S. Bureau of Mines discussing the recovery of magnesia from dolomite. Processes and methods of recovery are described. This report includes tables.