Abstract: A low-level airborne radioactivity survey of parts of Beaverhead and Madison Counties in southwestern Montana was undertaken from June 6 to October 14, 1955. Flying centered around the Ruby Range-Sweetwater Basin area and concentrated on the Precambrian metamorphic complex and Tertiary lake-bed sediments. No commercial uranium deposits were discovered, and no extensions were found of the few known small occurrences. Five areas of high background detected through the survey were investigated on the ground.

From abstract: The area comprising the first flood plain downstream from the headwaters of Knob Creek was one of three monazite placer deposits near Shelby, N. C., recommended by the Geological Survey for investigation by the Bureau of Mines as a joint effort by the above two agencies. Past production of monazite from the headwaters of this stream and its drainage of an area of known source rocks were factors influencing this selection. Drilling of the deposit was started on November 26, 1951, and completed December 29, 1951. Twenty-two churn-drill holes were completed to bed-rock on 112 acres of this flood plain for a total depth of 433 feet of vertical drilling.

From introduction: The purpose of this paper is to present the geologic facts which have been discovered thus far about the Lukachukai area and to draw conclusions about uranium mineralization. Basic data of general nature are included to facilitate the work of future geologists in this area who may find the information applicable to new ideas.

Abstract: The Wilson Creek Area, in northern Gila Cointy, is about 10 miles southeast of Young, Arizona, along the east side of Cherry Creek. Four claims covering concentrations of uranium mineralization in the Dripping Spring Formation are owned by the American Asbestos Cement Company. The claims are located in typical plateau-type topography, with flat mesa* and nearly vertical canyon walls. The bedded zones of uranium mineralization are exposed in the Dripping Spring Quartzite near the bottom of the canyons. It is suggested that the mineralized beds may have spatial relationship to the bottom of the Mescal limestone and to the bottom of a thick zone in the upper member of the quart site. Two of the four bedded deposits occur in *crackled" beds. One mineralized fracture was noted. The uranium mineral, meta-torbernite, has formed in tiny vugs in the quart site and is also intergrown with the iron oxide coating on the quart site surfaces. Associated minerals are minor and consist of chalcopyrite magnetite and chalcocite.

From purpose and scope: This report is designed to summarize the available information on the geology and ore reserves of the uranium deposits. Detailed geological work has been confined largely to those areas which contain the more promising uranium occurrences with at least 80 percent of such work being concentrated in the Sierra Ancha district.

Abstract: The Diamond Head droup area is entirely igneous. Tight fractures in alaskite and granite, which have been altered by heiratite and kaolinization contain narrow seams and very locally,pods of sooty uraninite. A greater percentage of the structures in the area strike about east-west and dip steeply to the north, while the radioactive structures have similar strike, they dip steeply to both the north and the south. A drift has been driven on a mineralized structure far enough to ascertain that the general character of the mineralization is very narrow seams. Many such seams exists but are scattered throughout the area.

From abstract: The subsurface isorad method is an attempt to locate areas favorable for uranium ores by the use of contour maps which show localities having greater radioactivity. The construction of isorad maps entails the measurement of the area under the curve of a gamma-ray logo The figures obtained indicate relative amounts of gamma radiation and are used to locate the isorad contours. This work was started at Temple Mountain in the San Rafael Swell area during the spring of 1952. The purpose of this investigation is to determine the most effective and economic hole spacing for subsurface isorad work.

Abstract: A four-week reconnaissance of certain portions of the mountainous area in Gila and Pinal Counties, Arizona, was undertaken in March and April, 1953, to inspect accessible outcrops of Dripping Spring quartzite, a pre-Cambrian formation which has lately attracted the interest of the Atomic Energy Commission by the discovery of two separate occurrences of uranium mineralization. Although no new deposits were found during the field work, a more thorough examination of the quartzite seems warranted. Recommendations for further prospecting by airborne and ground methods are presented in this report, and are based largely on observations made during the brief visit.

Introduction: From the inception of the effort to utilize atomic energy Perú has been of interest as a possible source of radioactive raw materials because of its great variety and abundance of metals. Because of this and a desire at that time to develop additional supplies of uranium, a cooperative program to search for uranium deposits was initiated in 1953 by the Junta and the USAEC.

Abstract: In September-October 1958 a six-day reconnaissance in the Tocopilla area, Antofagasta Province, Chile, was made by members of the U.S. Atomic Energy Commission and the Instituto de Investigaciones Geológicas de Chile for the purpose of evaluating reported uranium occurrences.

Abstract: In the Chañaral-Taltal area of northern Chile irregular replacement type iron deposits are especially well developed along a somewhat radioactive lithologic belt in andesite volcanic rocks and Cretaceous dioretic intrusions to the east of the Atacama fault, a prominent shear zone.

Abstract: In August 1958 two geologists of the Instituto de Investigaciones Geológicas de Chile made a one-week reconnaissance for uranium of the Arica area in northern Chile.

Abstract: A reconnaissance for uranium in and a general geologic study of the San Pedro de Atacama and Laco areas of nothern Chile disclosed no significant radioactivity in the Laco area, but near San Pedro de Atacama slight anomalies were detected in limey silts of the San Pedro formation.

From introduction: To improve understanding of uranium mineralization of the Todilto Limestone of Late Jurassic age in the Grants district, New Mexico, the mines active in 1957 were reviewed to determine the major types of deposits. A representative example of each type was selected and mapped in great detail to establish a prototype. It was hoped that the analysis of prototypes might shed considerable light on the mineralization process and aid evaluation of other deposits by offering a standard of comparison.

Although uranium gas first discovered in the Carrizo Mountains area in 1918, the ores were not developed until 1942. They have, however, been mined continuously since that time. Formations in the area range from the Pernian Cutler through the Cretaceous Mancos shale, and all are intruded by a dioritic laccolith and its related dikes. The older structures, which include the Defiance Uplift, the San Juan Basin, and the Four Corners Platform are somewhat disrupted by the effects of the intrusion. A number of mines are described and mineralogical and geochemical studies made are outlined. The primary uranium mineral is unknown, but the chief uranium ore-mineral is the secondary mineral, tyuyamunite. It is concluded that there is at least minor structural control of the ore bodies along sedimentary trends and joints, and that all ore bodies of 500 tons or more are on the Defiance monocline or its extensions. The uranium may have been syngenetic in the sediments, and redistributed by solutions or, more likely, that it rose vertically in hydrothermal solutions from the local intrusive bodies.

From Purpose, Scope, and Methods: The objective of this study was an evaluation of resources of the Carrizo Mountains area. Four factors: distribution of ore bodies, relation of uranium to the host rock, relation of ore to structure, and circumstances that might precipitate uranium were studied in search of data bearing on manner of distribution of ore, the time and causes of deposition, and the probable source of the uranium-bearing solutions.

Abstract: In a study of the comparative importance of sedimentary and tectonic ore controls and in search of data bearing on the origin of the deposits, ten mines in the Lukachukai Mountains, Apache County, Arizona were examined in detail. All commercial deposits in the area are in the Salt Wash Member of the Morrison Formation of Jurassic age. The ore bodies are elongate and horizontally lenticular in shape and consist of one or more ore pockets surrounded or separated by protore. The composite length of ore bodies consisting of two or more ore pockets separated by subore grade material ranges up to 1,100 feet; individual ore pockets range up to 350 feet in length. Elongation is usually at least three times the width and is parallel to paleostream depositional trends measured in and near the ore bodies. Claystone and/or siltstone units nearly always underlie and frequently overlie the host sandstone units. Ore occurs most frequently in trough-type, cross-stratified sandstone which fills scours and channels in the underlying claystone units. Lithofacies maps and mine mapping show that ore bodies are restricted to areas of rapid lateral color change which in general are also areas of rapid change in the ratio of …

Abstract: Ten days were spent during June 1955, examining the sedimentary rocks along the San Juan and Colorado Rivers between Mexican Hat, Utah, and Lee's Ferry, Arizona. The most favorable area for uranium deposits occurs in the Shinarump member of the Chinle formation between Clay Hills Crossing and Spencer Camp along the San Juan River. Mineralization is spotty and deposits are small and almost all below ore-grade. Only one small mine, the Whirlwind, is currently producing ore. Gray-green alteration of the underlying Moenkopi is moderately developed in the vicinity of the Whirlwind mine; elsewhere alteration is weakly developed.

Abstract: From December 1953 to May 1954 an extensive airborne reconnaissance program was conducted in northwestern Arizona (Arizona Strip) and southwestern Utah. Five surface anomalies were detected, one of which has possible commercial value. All anomalies are within the boundaries of National Park Service jurisdiction, consequently, this report is not for public distribution until clearance is obtained from the National Park Service. A preliminary airborne reconnaissance program was also conducted in the Richfield area. No anomalies were discovered.

From introduction: This report is written in response to a request from the Army Engineers for an appraisal of the uranium potential of the area included in the Yams Test Station. the area of Proposed Expansion of the Yuma Test Station, and the Williams Bombing and Gunnery Range. Only the area covered by the present Yuma Test Station is included here. The other areas will be discussed In subsequent reports.

Abstract: A low-level airborne radiometric survey of the younger pre-Cambrian Dripping Spring quartzite, undertaken in the mountainous region lying roughly 100 riles east of Phoenix, was completed June 3, 1955. Twenty-seven radioactive anomalies were located. To date seven of these have produced uranium ore, four more will probably become producers, and six others may possibly become producers. Flying was concentrated in the Dripping Spring quartzite, but reconnaissance flights were made over other formations. Private prospecting, both from the air and on the ground, increased considerably when the airborne project started. Eleven of the private discoveries have produced ore, and many others show considerable promise.

From purpose and scope: and primary objective was to determine the extent and grade of ore present and the future potential of the district. The second and broader objective was to learn the relationship of ore to stratigraphy and structure, in order to outline similar areas favorable for prospecting.

This book presents reconnaissance reports for uranium deposits in Mohave County, Arizona from 1952 to 1956.

Abstract: An exploratory wagon drilling program was conducted from May 2, 1953, to October 31, 1953, on the Silver Crown, Big Hill, and Silverman claims of Western Gold and Uranium Mines, Inc. at the Silver Reef district near Leeds, Utah. Two economically significant new ore bodies were discovered and considerable geological information gained. The Silver Reef uranium deposits are located near the faulted north-plunging nose of the Virgin anticline in an old silver mining' district. Silver, uranium, vanadium, and copper minerals occur in association with various carbonaceous, sandy shale horizons of the Leeds and Tecumseh members of the Triassic Chinle formation. Mineralization has favored areas where relatively close-spaced normal faults of very small displacement cut the favorable beds.