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USGS2001

Geologic map of the Rifle Falls quadrangle, Garfield County, Colorado

New 1:24,000-scale geologic map of the Rifle Falls 7.5' quadrangle, in support of the USGS Western Colorado I-70 Corridor Cooperative Geologic Mapping Project, provides new interpretations of the stratigraphy, structure, and geologic hazards in the area of the southwest flank of the White River uplift. Bedrock strata include the Upper Cretaceous Iles Formation through Ordovician and Cambrian units. The Iles Formation includes the Cozzette Sandstone and Corcoran Sandstone Members, which are undivided. The Mancos Shale is divided into three members, an upper member, the Niobrara Member, and a lower member. The Lower Cretaceous Dakota Sandstone, the Upper Jurassic Morrison Formation, and the Entrada Sandstone are present. Below the Upper Jurassic Entrada Sandstone, the easternmost limit of the Lower Jurassic and Upper Triassic Glen Canyon Sandstone is recognized. Both the Upper Triassic Chinle Formation and the Lower Triassic(?) and Permian State Bridge Formation are present. The Pennsylvanian and Permian Maroon Formation is divided into two members, the Schoolhouse Member and a lower member. All the exposures of the Middle Pennsylvanian Eagle Evaporite intruded into the Middle Pennsylvanian Eagle Valley Formation, which includes locally mappable limestone beds. The Middle and Lower Pennsylvanian Belden Formation and the Lower Mississippian Leadville Limestone are present. The Upper Devonian Chaffee Group is divided into the Dyer Dolomite, which is broken into the Coffee Pot Member and the Broken Rib Member, and the Parting Formation. Ordovician through Cambrian units are undivided. The southwest flank of the White River uplift is a late Laramide structure that is represented by the steeply southwest-dipping Grand Hogback, which is only present in the southwestern corner of the map area, and less steeply southwest-dipping older strata that flatten to nearly horizontal attitudes in the northern part of the map area. Between these two is a large-offset, mid-Tertiary(?) Rifle Falls normal fault, that dips southward placing Leadville Limestone adjacent to Eagle Valley and Maroon Formations. Diapiric Eagle Valley Evaporite intruded close to the fault on the down-thrown side and presumably was injected into older strata on the upthrown block creating a blister-like, steeply north-dipping sequence of Mississippian and older strata. Also, removal of evaporite by either flow or dissolution from under younger parts of the strata create structural benches, folds, and sink holes on either side of the normal fault. A prominent dipslope of the Morrison-Dakota-Mancos part of the section forms large slide blocks that form distinctly different styles of compressive deformation called the Elk Park fold and fault complex at different parts of the toe of the slide. The major geologic hazard in the area consist of large landslides both associated with dip-slope slide blocks and the steep slopes of the Eagle Valley Formation and Belden Formation in the northern part of the map. Significant uranium and vanadium deposits were mined prior to 1980.

Colorado↗

USGS2001

Laboratory measurements of electrical properties of composite mine dump samples from Colorado and New Mexico

Individual mine waste samples were collected and combined to form one composite sample at each of eight mine dump sites in Colorado and New Mexico. The samples were air-dried and sieved to determine the geochemical composition of their <2mm size fraction. Splits of the samples were then rehydrated and their electrical properties were measured in the US Geological Survey Petrophysical Laboratory, Denver, Colorado (PetLab). The PetLab measurements were done twice: in 1999, using convenient amounts of rehydration water ranging from 5% to 8%; and in 2000, using carefully controlled rehydrations to 5% and 10% water. This report gives geochemical analyses of the <2mm size fraction of the composite samples (Appendix A), PetLab graphs of the 1999 measurements (Appendix B), Petlab graphs of the 2000 measurements (Appendix C), and Cole-Cole models of the PetLab data from the 2000 measurements (Appendix D).

Colorado↗

USGS2025

Contributions of erosion, deposition, and human activities to a change in sand storage in the bed of San Francisco Bay, California, 1980s to 2010s

This study by the U.S. Geological Survey (USGS) provides estimates of the change in sand storage in bed sediments from the 1980s to 2010s in the San Francisco Bay area, California. The study is part of a larger project called “Research to Understand Impacts of Bay Sand Mining on Sand Transport in San Francisco Bay and the Outer Coast” that has the goal of providing information for the California Coastal Conservancy to inform decision making regarding sand mining activities. Information from this study will contribute to the sand budget for the San Francisco Bay system by accounting for sand made available by erosion of bay sediment and sequestered by deposition in the bay. Sediment budgets for estuaries typically account for change in sediment storage in the bed without discriminating for sediment size. However, the physics of mud and sand erosion, deposition, and transport differ. Sediment budgets that treat mud and sand separately give a more complete understanding of the system, including how human activities related to sediment size, such as sand mining, affect the system. We used bathymetric change analysis in combination with a three-dimensional model to generate estimates of net change in sand storage within the San Francisco Bay floor. We document sediment volume change from a 1980s bathymetric surface to a 2010s bathymetric surface, in combination with information on the sand content of the bed sediment derived from sediment cores and surface samples from six different sediment studies, to estimate the net change in sand volume in the bed of San Francisco Bay. This analysis includes areas heavily affected by human activities (such as sand mining, dredging, and sediment disposal) as well as regions more representative of natural transport processes. Overall, the sediment bed of San Francisco Bay is losing sand. Across the total area surveyed in San Francisco Bay, including areas affected by natural processes, oyster shell beds, and human activities, a net loss of about 17 million cubic meters (Mm 3 ) of sand from the sediment bed occurred from the 1980s to 2010s, at a rate of about 0.8 Mm 3 per year. For the period of this study, sand loss from bed level changes in permitted sand-lease mining areas (about 11 Mm 3 ) accounts for about two-thirds of the total sand loss throughout the study area. It is important to consider potential uncertainty bounds when interpreting these findings. A key part of the report is an assessment of the uncertainties in our estimates of sand volumes. We estimate that variability in modeled sand content values of Bay floor sediments could result in an uncertainty of approximately 25 percent of the net sand volume change. Even larger uncertainty amounts may be associated with uncertainty in the systematic errors in the bathymetric surveys. Further refining estimates of uncertainty in bathymetric change is important in guiding the use of this study. The results presented here can fill a critical gap that may enable the creation of the first comprehensive sand budget of San Francisco Bay.

California↗

USGS1982

Geologic report and recommendations for the cobalt mission to Morocco sponsored by The Trade and Development Program of the International Development Cooperation Agency

A mission sponsored by the Trade and Development Program (TDP) of the International Development Cooperation Agency (IDCA) went to Morocco to evaluate the possibility of finding additional sources of cobalt in that country, as well as other types of mineralization. Information obtained during this trip shows Morocco to be a country for which much geologic information is available and in which there are many favorable target areas for future exploration. Work in the Bou Azzer district (Morocco's principal cobalt district) shows that much excellent geologic work has been done in searching for additional deposits. However, a number of useful approaches to locate cobalt have not been tried, and their use might be successful. The potential for undiscovered deposits in the Bou Azzer region seems very high. The cobalt mineralization in the Siroua uplift is different from that in the Bou Azzer district. However, geologic similarities between the two areas suggest that a genetic link may exist between the two types of mineralization. This further indicates that cobalt deposits of the Bou Azzer types might be present in the Siroua region. Examination of the Bleida copper mine shows it to be a well-exposed volcanic hosted stratabound copper deposit. Large unexplored areas containing similar rocks occur near this deposit and may contain as yet undiscovered copper mineralization.

Open-File Report↗

USGS2020

Simulation of discharge, water-surface elevations, and water temperatures for the St. Louis River estuary, Minnesota-Wisconsin, 2016–17

The St. Louis River estuary is a large freshwater estuary, next to Duluth, Minnesota, that encompasses the headwaters of Lake Superior. The St. Louis River estuary is one of the most complex and compromised near-shore systems in the upper Great Lakes with a long history of environmental contamination caused by logging, mining, paper mills, and other heavy industrial activities. Presently (2020), a widely available, science-based assessment tool capable of evaluating ecosystem-level responses to remediation and restoration projects has not existed for the estuary. To address this need, the U.S. Geological Survey (USGS) built a predictive, mechanistic, three-dimensional hydrodynamic model for the estuary using the Environmental Fluid Dynamics Code framework. In the current version, the model can simulate continuous discharge, water-surface elevations, water temperature, and flow velocity, although the modular framework allows for future additions of water-quality modeling. The model was calibrated using data collected from April 2016 through November 2016 and validated with data collected from April 2017 through November 2017. The four types of data used to evaluate model performance were water-surface elevations, discharge, water temperature, and flow velocities. Streamflow and temperature boundary condition data included a mixture of USGS streamgage data, Minnesota Department of Natural Resources gage data, and estimates derived from the gage data. The model was able to simulate the water-surface elevations with generally good agreement between the simulated and measured values for both years at the daily time step. Specifically, the model was able to demonstrate excellent agreement with the measured data with Nash-Sutcliffe efficiency coefficients greater than 0.8 for all three locations; however, the model was unable to produce hourly water-surface elevations with such accuracy for 2016–17. Discharge was more dynamic than the water-surface elevations, both for the measured and simulated data. Generally, most of the discharge ranged from −650 to 1,200 cubic meters per second, but the constantly changing flux exiting the estuary into Lake Superior (positive flows) and entering the estuary from Lake Superior (negative flows) occurred throughout the year. Even upstream at the St. Louis River at Oliver, Wisconsin, gage (USGS station 0402403250), the effect of flows into the estuary from Lake Superior did occur, demonstrating the strong effect of the Lake Superior seiche on flows for the estuary. From a performance standpoint, the model was able to simulate discharge with generally good agreement in both years, although the 2017 validation was better than the 2016 calibration period. For the daily Nash-Sutcliffe efficiency coefficients, the simulated values were 0.98, 0.62, 0.49, and 0.71 for the Oliver gage; the Superior Bay entry channel at Superior, Wisc., (USGS station 464226092005600); the Superior Bay Duluth Ship Canal at Duluth, Minn., (USGS station 464646092052900); and total entries (combination of the Superior entry and Duluth entry), respectively. For the hourly evaluation criteria, the model performed poorly, with Nash-Sutcliffe efficiency coefficients less than 0 for the two entries into Lake Superior; therefore, as a predictor of discharge at the hourly scale, the model performed worse than using the measured data average. Similar to discharge, the model was a good predictor of flow velocity at the daily time scale but had difficulty matching the measured data at the hourly scale. For discharge and flow velocity, matching at subdaily time steps for a system as complicated as the St. Louis River estuary is considered difficult because the match is highly sensitive to coordinating the exact measurement location to the simulated value. The final calibration target was water temperature, calibrated for the Oliver gage and the Duluth entry. For calibration purposes, the Duluth entry was the more important water temperature target because the Oliver gage was more of an internal check on the model. The Nash-Sutcliffe efficiency coefficients for the Duluth entry were high; hourly Nash-Sutcliffe efficiency coefficients at the Duluth entry were either at or greater than 0.7 for both years, and daily values were 0.84 and 0.82 for 2016 and 2017, respectively.

Minnesota, Wisconsin↗

USGS1996

Estimated Freshwater Withdrawals in Oklahoma, 1990

This report presents 1990 freshwater withdrawal estimates for Oklahoma by source and category. Withdrawal source is either ground water or surface water. Withdrawal categories include: irrigation, water supply, livestock, thermoelectric-power generation, domestic and commercial, and industrial and mining. Withdrawal data are aggregated by county, major aquifer, and principal river basin. Only the four major categories of irrigation, water supply, livestock, and thermoelectric-power generation are illustrated in this report, although data for all categories are tabulated. The U.S. Geological Survey (USGS) established the National Water-Use Information Program in 1977 to collect uniform, current, and reliable information on water use. The Oklahoma District of the USGS and the Oklahoma Water Resources Board participate in a cooperative program to collect and publish water-use information for Oklahoma. Data contained in this report were made available through the cooperative program.

Water-Resources Investigations Report↗

USGS2024

Minerals Yearbook, volume III, Area Reports — International

The U.S. Geological Survey (USGS) Minerals Yearbook discusses the performance of the worldwide minerals and materials industries and provides background information to assist in interpreting that performance. Content of the individual Minerals Yearbook volumes follows: Volume I, Metals and Minerals , contains chapters about virtually all metallic and industrial mineral commodities important to the U.S. economy. Chapters on survey methods, summary statistics for domestic nonfuel minerals, and trends in mining and quarrying in the metals and industrial mineral industries in the United States are also included. Volume II, Area Reports: Domestic , contains a chapter on the mineral industry of each of the 50 States and Puerto Rico and the Administered Islands. This volume also has chapters on survey methods and summary statistics of domestic nonfuel minerals. Volume III, Area Reports: International , is published as four separate reports. These regional reports contain the latest available minerals data on more than 180 foreign countries and discuss the importance of minerals to the economies of these nations and the United States. Each report begins with an overview of the region’s mineral industries during the year. It continues with individual country chapters that examine the mining, refining, processing, and use of minerals in each country of the region and how each country’s mineral industry relates to U.S. industry. Most chapters include production tables and industry structure tables, information about Government policies and programs that affect the country’s mineral industry, and an outlook section. The USGS continually strives to improve the value of its publications to users. Constructive comments and suggestions by readers of the Minerals Yearbook are welcome.

Minerals Yearbook↗

USGS1995

U.S. Geological Survey Subsidence Interest Group conference, Edwards Air Force Base, Antelope Valley, California, November 18-19, 1992; Abstracts and summary

Land subsidence, the loss of surface elevation as a result of the removal of subsurface support, affects every state in the United States. More than 17,000 mi 2 of land in the United States has been lowered by the various processes that produce land subsidence with annual costs from resulting flooding and structural damage that exceed $125 million. It is estimated that an additional $400 million is spent nationwide in attempts to control subsidence. Common causes of land subsidence include the removal of oil, gas, and water from underground reservoirs; dissolution of limestone aquifers (sinkholes); underground mining activities; drainage of organic soils; and hydrocompaction (the initial wetting of dry soils). Overdrafting of aquifers is the major cause of areally extensive land subsidence, and as ground-water pumping increases, land subsidence also will increase. Land subsidence and its effects on engineering structures have been recognized for centuries, but it was not until this century that the processes that produce land subsidence were identified and understood. In 1928, while working with field data from a test of the Dakota Sandstone aquifer, O.E. Meinzer of the U.S. Geological Survey recognized the compressibility of aquifers. Around the same time, Karl Terzaghi, a soil scientist working at Harvard University, developed the one-dimensional consolidation theory that provided a quantitative means of predicting soil compaction resulting from the drainage of compressible soils. Thus, with the recognition of the compressibility of aquifers (Meinzer), and the development of a quantitative means of predicting soil compaction as a consequence of the reduction of intergranular pore pressure (Terzaghi), the theory of aquifer-system compaction was formed. With the widespread availability of electric power in rural areas, and the advent of the deep turbine pump, ground-water withdrawals increased dramatically throughout the country in the 1940's and 1950's. Along with this unprecedented increase in pumpage, substantial amounts of land subsidence were observed in several areas of the United States, most notably in Arizona, California, and Texas. Beginning in 1955, under the direction of Joseph Poland, the Geological Survey began the "Mechanics of Aquifers Project," which focused largely on the processes that resulted in land subsidence due to the withdrawal of ground water. This research team gained international renown as they advanced the scientific understanding of aquifer mechanics and land-subsidence theory. The results of field studies by members of this research group not only verified the validity of the application of Terzaghi's consolidation theory to compressible aquifers, but they also provided definitions, methods of quantification, and confirmation of the interrelation among hydraulic head declines, aquifer-system compaction, and land subsidence. In addition to conducting pioneering research, this group also formed a "center of expertise," providing a focal point within the Geological Survey for the dissemination of technology and scientific understanding in aquifer mechanics. However, when the "Mechanics of Aquifers Project" was phased out in 1984, the focal point for technology transfer no longer existed. Interest among various state and local agencies in land subsidence has persisted, and the Geological Survey has continued to participate in a broad spectrum of cooperative and Federally funded projects in aquifer mechanics and land subsidence. These projects are designed to identify and monitor areas with the potential for land subsidence, to conduct basic research in the processes that control land subsidence and the development of earth fissures, as well as to develop new quantitative tools to predict aquifer-system deformation. In 1989 an ad hoc "Aquifer Mechanics and Subsidence Interest Group" (referred to herein as the "Subsidence Interest Group") was formed

California↗

USGS1982

Geology of the Jabal Riah area, Kingdom of Saudi Arabia

The Jabal Riah area is in the southern part of the Jibal al Hamdah quadrangle (lat 19?00'00'' to 19?07'S0'' N., long 45?37'30'' to 43?45'00' E.) in the southeastern Precambrian Shield, Asir Province, Kingdom of Saudi Arabia. The Jabal Mahanid group of ancient gold mines, which is part of the Jabal Ishmas-Wadi Tathlith gold belt, is in the west-central part of the area. Rocks in the Jabal Riah area consist of Precambrian layered metasedimentary and metavolcanic rocks intruded by Precambrian igneous rocks. The metamorphic rocks are, from oldest to youngest, interlayered hornblende and biotite schist, quartz-biotite schist, hornblende schist, serpentinite, and chlorite schist. The igneous rocks are, from oldest to youngest, diorite-gabbro including dikes, granodiorite, monzogranite-granodiorite, leucocratic quartz porphyry, rhyolite, and aplite and pegmatite dikes. A large area of jasper replaces serpentinite. On the valley floors, recent alluvium and pediment deposits overlie the bedrock. The structure of the area is dominated by a dome centered over the eastern border of the area; leucocratic quartz porphyry forms the core of the dome. Minor folds and faults are present. The Jabal Mahanid group of ancient gold mines is on a northwest-trending vein system, and major ancient mine areas are found where the system splits or changes direction. The veins consist of zones of brecciated and crushed rock, which are generally less than 0.5 m wide but may be as wide as 1 m. These zones contain quartz and calcite stringers and commonly are along hornblende schist-serpentinite contacts; however, they also cut both units. Most aplite, pegmatite, and quartz dikes in the area are thin and discontinuous and are intruded along the vein trend. Similar veins, at the same stratigraphic interval, have been found beyond the northeastern part of the map area. The veins contain detectable gold and silver (median gold, approximately 0.14 ppm; median silver, approximately 1 ppm). Gold and silver are most abundant in calcium-rich rocks and veins; silver was not detected in igneous rocks. Altered wall-rock zones are mineralized as much as 10 m away from the veins. Away from the Jabal Mahanid vein-system, silver was detected in the jasper. Gold and silver were detected in minor brecciated and sheared structures and in metasedimentary rocks. Gold was detected in sericitized margins of the leucocratic quartz porphyry, in unaltered rhyolite, and in aplite dikes. The presence of unusual amounts of gold and silver over a wide area is indicated by the ancient gold mines along veins at or near the hornblende schist-serpentinite contact in the map area and to the south in the Hajrah-Hamdah area and by the widespread evidence of precious metals in igneous rocks and other vein structures. A domed-shaped area, approximately 30 km in diameter, is outlined by the hornblende schist-serpentinite contact and has leucocratic quartz prophyry in the middle. Additional study of this area might reveal economic concentrations of gold and silver.

Open-File Report↗

USGS1975

A brief history of the U.S. Geological Survey

Established by an Act of Congress in 1879 and charged with responsibility for "classification of the public lands, and examination of the geological structure, mineral resources, and products of the national domain," the U. S. Department of the Interior's Geological Survey has been the Nation's principal source of information about its physical resources the configuration and character of the land surface, the composition and structure of the underlying rocks, and the quality, extent, and distribution of water and mineral resources. Although primarily a research and fact-finding agency, it has responsibility also for the classification of Federal mineral lands and waterpower sites, and since 1926 it has been responsible for the supervision of oil and mining operations authorized under leases on Federal land. From the outset, the Survey has been concerned with critical land and resource problems. Often referred to as the Mother of Bureaus, many of its activities led to the formation of new organizations where a management or developmental function evolved. These included the Reclamation Service (1902), the Bureau of Mines (1910), the Federal Power Commission (1920), and the Grazing Service (1934, since combined with other functions as the Bureau of Land Management). Mrs. Rabbitt's summary of the Survey's history in the following pages brings out well the development of these diverse activities and the Survey's past contributions to national needs related to land and resources.

General Information Product↗

USGS1993

Regional and economic geology of Pennsylvanian age coal beds of West Virginia

West Virginia is the only place in the United States where an entire section of Pennsylvanian age (Upper Carboniferous) strata can be seen. These strata occur within a wedge of rock that thins to the north and west from the southeastern part of the State. The progressive north-northwesterly termination of older Pennsylvanian geologic units beneath younger ones prominently outlines the center of the Appalachian basin of West Virginia. Over most of West Virginia, Lower and/or Middle Pennsylvanian strata unconformably overly Upper Mississippian (Lower Carboniferous) strata. Sediment deposition was accomplished by a complex system of deltas prograding north and west from an eastern and southeastern source area. More than 100 named coal beds occur within the Lower, Middle, and Upper Pennsylvanian rocks of West Virginia and at least 60 of these have been or are currently being mined commercially. Collectively, these coal beds account for original in-ground coal resources of almost 106.1×10 9 t (117×10 9 tons). West Virginia ranks fourth in the United States in demonstrated coal reserves. In 1988, West Virginia produced 131.4×10 6 t (144.9×10 6 T) of coal, third highest in the United States. Of this annual production, 75% was from underground mines. In 1988, West Virginia led the nation in the number of longwall mining sections currently in place. West Virginia's low-volatile coal beds are known worldwide as important metallurgical-grade coals, while the higher-volatile coal beds are utilized primarily for steam production.

International Journal of Coal Geology↗

USGS2010

A Servicewide Benthic Mapping Program for National Parks

In 2007, the National Park Service (NPS) Inventory and Monitoring Program directed the initiation of a benthic habitat mapping program in ocean and coastal parks in alignment with the NPS Ocean Park Stewardship 2007-2008 Action Plan. With 74 ocean and Great Lakes parks stretching over more than 5,000 miles of coastline across 26 States and territories, this Servicewide Benthic Mapping Program (SBMP) is essential. This program will deliver benthic habitat maps and their associated inventory reports to NPS managers in a consistent, servicewide format to support informed management and protection of 3 million acres of submerged National Park System natural and cultural resources. The NPS and the U.S. Geological Survey (USGS) convened a workshop June 3-5, 2008, in Lakewood, Colo., to discuss the goals and develop the design of the NPS SBMP with an assembly of experts (Moses and others, 2010) who identified park needs and suggested best practices for inventory and mapping of bathymetry, benthic cover, geology, geomorphology, and some water-column properties. The recommended SBMP protocols include servicewide standards (such as gap analysis, minimum accuracy, final products) as well as standards that can be adapted to fit network and park unit needs (for example, minimum mapping unit, mapping priorities). SBMP Mapping Process. The SBMP calls for a multi-step mapping process for each park, beginning with a gap assessment and data mining to determine data resources and needs. An interagency announcement of intent to acquire new data will provide opportunities to leverage partnerships. Prior to new data acquisition, all involved parties should be included in a scoping meeting held at network scale. Data collection will be followed by processing and interpretation, and finally expert review and publication. After publication, all digital materials will be archived in a common format. SBMP Classification Scheme. The SBMP will map using the Coastal and Marine Ecological Classification Standard (CMECS) that is being modified to include all NPS needs, such as lacustrine ecosystems and submerged cultural resources. CMECS Version III (Madden and others, 2010) includes components for water column, biotic cover, surface geology, sub-benthic, and geoform. SBMP Data Archiving. The SBMP calls for the storage of all raw data and final products in common-use data formats. The concept of 'collect once, use often' is essential to efficient use of mapping resources. Data should also be shared with other agencies and the public through various digital clearing houses, such as Geospatial One-Stop (http://gos2.geodata.gov/wps/portal/gos). To be most useful for managing submerged resources, the SBMP advocates the inventory and mapping of the five components of marine ecosystems: surface geology, biotic cover, geoform, sub-benthic, and water column. A complete benthic inventory of a park would include maps of bathymetry and the five components of CMECS. The completion of mapping for any set of components, such as bathymetry and surface geology, or a particular theme (for example, submerged aquatic vegetation) should also include a printed report.

Open-File Report↗

USGS2011

Overview of flow studies for recycling metal commodities in the United States

Metal supply consists of primary material from a mining operation and secondary material, which is composed of new and old scrap. Recycling, which is the use of secondary material, can contribute significantly to metal production, sometimes accounting for more than 50 percent of raw material supply. From 2001 to 2011, U.S. Geological Survey (USGS) scientists studied 26 metals to ascertain the status and magnitude of their recycling industries. The results were published in chapters A-Z of USGS Circular 1196, entitled, "Flow Studies for Recycling Metal Commodities in the United States." These metals were aluminum (chapter W), antimony (Q), beryllium (P), cadmium (O), chromium (C), cobalt (M), columbium (niobium) (I), copper (X), germanium (V), gold (A), iron and steel (G), lead (F), magnesium (E), manganese (H), mercury (U), molybdenum (L), nickel (Z), platinum (B), selenium (T), silver (N), tantalum (J), tin (K), titanium (Y), tungsten (R), vanadium (S), and zinc (D). Each metal commodity was assigned to a single year: chapters A-M have recycling data for 1998; chapters N-R and U-W have data for 2000, and chapters S, T, and X-Z have data for 2004. This 27th chapter of Circular 1196 is called AA; it includes salient data from each study described in chapters A-Z, along with an analysis of overall trends of metals recycling in the United States during 1998 through 2004 and additional up-to-date reviews of selected metal recycling industries from 1991 through 2008. In the United States for these metals in 1998, 2000, and 2004 (each metal commodity assigned to a single year), 84 million metric tons (Mt) of old scrap was generated. Unrecovered old scrap totaled 43 Mt (about 51 percent of old scrap generated, OSG), old scrap consumed was 38 Mt (about 45 percent of OSG), and net old scrap exports were 3.3 Mt (about 4 percent of OSG). Therefore, there was significant potential for increased recovery from scrap. The total old scrap supply was 88 Mt, and the overall new-to-old-scrap ratio was 36:64. On a weighted-average basis, the recycling rate overall for these metals was 40 percent, and the estimated efficiency of recovery was 63 percent. New scrap consumed was 21 Mt. The United States was a net exporter of most scrap metals, and the net exports of 3.3 Mt were valued at $2 billion in constant 1998 dollars. Metals show a wide range of recycling rates, recycling efficiency, and new-to-old-scrap ratios. Recycling rates cluster in the range from 15 to 45 percent, whereas efficiencies are fairly evenly distributed over a range from 7 to 97 percent.

Circular↗

USGS1984

Phosphate rock resources of the United States

In 1980, the United States produced about 54 million tons of phosphate rock, or about 40 percent of the world's production, of which a substantial amount was exported, both as phosphate rock and as chemical fertilizer. During the last decade, predictions have been made that easily ruinable, low-cost reserves of phosphate rock would be exhausted, and that by the end of this century, instead of being a major exporter of phosphate rock, the United States might become a net importer. Most analysts today, however, think that exports will indeed decline in the next one or two decades, but that resources of phosphate are sufficient to supply domestic needs for a long time into the future. What will happen in the future depends on the actual availability of low-cost phosphate rock reserves in the United States and in the world. A realistic understanding of future phosphate rock reserves is dependent on an accurate assessment, now, of national phosphate rock resources. Many different estimates of resources exist; none of them alike. The detailed analysis of past resource estimates presented in this report indicates that the estimates differ more in what is being estimated than in how much is thought to exist. The phosphate rock resource classification used herein is based on the two fundamental aspects of a mineral resource(l) the degree of certainty of existence and (2) the feasibility of economic recovery. The comparison of past estimates (including all available company data), combined with the writers' personal knowledge, indicates that 17 billion metric tons of identified, recoverable phosphate rock exist in the United States, of which about 7 billion metric tons are thought to be economic or marginally economic. The remaining 10 billion metric tons, mostly in the Northwestern phosphate district of Idaho, are considered to be subeconomic, ruinable when some increase in the price of phosphate occurs. More than 16 billion metric tons probably exist in the southeastern Coastal Plain phosphate province, principally in Florida and North Carolina and offshore in the shallow Atlantic Ocean from North Carolina to southern Florida. This resource is considered to be hypothetical because it is based on geologic inference combined with sparse drilling data. Total resources of phosphate rock in the United States are sufficient to supply domestic demands for the foreseeable future, provided that drilling is done to confirm hypothetical resources and the chemistry of the deposits is determined. Mining and beneficiation techniques will have to be modified or improved, and new techniques will have to be developed so that these deposits can be profitably exploited.

Circular↗

USGS1954

Geology and coal deposits of the Shelburn quadrangle, Sullivan County, Indiana

The Shelburn quadrangle is the fifth in a series of quadrangle maps prepared as a part of a program by the Geological Survey, Indiana Department of Conservation, and the U.S. Geological Survey to appraise the coal resources of Indiana. The field work was done by the writer, assisted by Dick S. Horton and Robert E. Hurley, during the summer of 1949 and for a short period during the summer of 1950. Data on mines, records of past production, and records of exploratory drilling for coal and oil were provided by the operators in the quadrangle, whose help and advice has been most helpful in the preparation of this report. The Indiana Bureau of Mines and Mining provided much valuable information on abandoned mines in the quadrangle.

Indiana↗

USGS2006

Preliminary estimate of coal resources in the Gillette coalfield affected by the location of the Burlington Northern/Union Pacific joint mainline railroad

This publication, primarily in graphic form, presents a preliminary resource assessment related to a major, near-term restriction to mining in that portion of the Gillette coalfield, Wyoming, that is traversed by the Burlington Northern/Union Pacific joint mainline railroad. This assessment is part of a current Powder River Basin regional coal assessment, including both resources and reserves, being conducted by the U.S. Geological Survey. The slides were used to illustrate a presentation of study results at a meeting of the Bureau of Land Management's Regional Coal Team in Casper, Wyoming on April 19, 2006 by the senior author.

Open-File Report↗

USGS1949

Coal investigations on the southern margin of the Homer district, Kenai coal field, Alaska, in 1947-48

The presence of coal in the Tertiary Kenai formation of western Kenai Peninsula has been known since 1880, chiefly as exposed along the north shore of Kachemak Bay and the adjoining east shore of Cook Inlet (fig. 1). Several early attempts were made to develop a commercial mine in this area in the period 1888-1902 but none progressed beyond the prospecting stage and little coal was produced. In 1915 the mining of coal-was started at the Bluff Point mine, 1 1/2 miles west of Homer. Available records indicate that this mine produced between 20,000 and 25,000 tons of coal before closing in 1324. No further attempt at mining was made until 1946, when the Homer Coal Corporation began development near the site of the old Bluff Point mine. Development work during 1946 and 1947 included construction of a truck-loading bunker, mess hail, bunkhouse, and an incline end hoist for raising coal from the tunnel in the face of the beach bluff. Only a small amount of underground work was done in 1946 and 1947, and practically none in 1948. A preliminary step toward more extended investigation of the coal deposits of the Homer district was made by the writer, accompanied by T. J. Jolley of the U. S. Bureau of Mines, in the summer of 1946. Several days were spent in examining the principal coal exposures near Homer and collecting samples to determine the desirability of more detailed investigation. Detailed examination of the coal deposits of the Homer district was started by the Geological Survey in 1947. The period July 17 to September 14 was spent by the writer, assisted by H. C. Wagner, geologist, and L. A. Hale, field assistant, in reconnaissance of isolated coal exposures in an area extending several miles north of Homer, and in measuring detailed stratigraphic sections in the bluffs just north of Homer between Coal (Bidarki) and Fritz Creeks.

Alaska↗

USGS1955

Pegmatites of the Middletown area, Connecticut

The pegmatites of the Middletown area in Connecticut have been mined almost continuously for feldspar and muscovite mica since about 1865, Pegmatites in this and other areas have recently become the subject of renewed interest because pegmatites are the potential source of beryl, the ore mineral of beryllium. During 1948 to 1950, the Geological Survey studied and mapped the pegmatites in an area of about 58 square miles near Middletown. The primary objectives of the mapping were to determine beryllium resources of the Middletown area, and to ascertain relationships of beryl-bearing pegmatites to non-beryl-bearing pegmatites and to type of wall rock.

Connecticut↗