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34 records · Page 2Linked to original sources
USGS1975

Ore grade, metal production, and energy

Recent resource estimates have been stimulated by national concern over present and pending shortages of energy and mineral resources. Although some believe that the resource base of a commodity is the total amount in the crust, the energy consumption for mining and milling under present technology suggests that grades of the metallic ores have a lower limit when production is assumed to be for common usages. The tonnage required to mine and mill ores to obtain one unit of metal is a hyperbolic function of the grade, and as the tonnage increases hyperbolically, so does the energy consumed. For copper, the hyperbolic relation suggests that deposits with grades below about 0.20-0.25 percent Cu will not be mined to produce metal for common electrical and construction uses. Although the energy used to mine and mill a unit of metal differs from one metal to another, all show the hyperbolic increase in energy consumption as grade decreases.

Journal of Research of the U.S. Geological Survey↗
USGS1982

Geochemical reconnaissance for uranium occurrences in the Notch Peak intrusive area, House Range, Millard County, Utah

Samples collected from the contact metamorphic zone of the Notch Peak intrusive area, House Range, Millard County, Utah, indicate the occurrence of low-grade uranium and thorium ore. Maximum abundances in the altered mineralized rocks in the contact zone are 450 ppm uranium and 480 ppm thorium. Interpretation of factor analysis of the spectrochemical and delayed neutron analytical data suggests the presence of five geological factors which account for 82 percent of element covariance of 34 elements in 61 samples. The factors are identified as (1) limestone source rock reactions; (2) monzonite source rock reactions; (3) hydrothermal element group 1; (4) rare earth group; and (5) hydrothermal element group 2. The last factor effects the distribution of, primarily, beryllium, uranium, copper, molybdenum, tungsten, niobium, and secondarily, thorium, tin, and zinc; it is identified as the prime mineralization factor. The Notch Peak intrusive area has been a tungsten producing area since before the 1940's and the location of small-scale gold placer operations. This reconnaissance study was a 'follow-up' of uranium anomaly data which were developed during the U.S. Dept. of Energy National Uranium Resource Evaluation (NURE) program in 1978-80.

Open-File Report↗
USGS2018

A practical primer on geostatistics

Introduction The Challenge —Most geological phenomena are extraordinarily complex in their interrelationships and vast in their geographical extension. Ordinarily, engineers and geoscientists are faced with corporate or scientific requirements to properly prepare geological models with measurements involving a small fraction of the entire area or volume of interest. Exact description of a system such as an oil reservoir is neither feasible nor economically possible. The results are necessarily uncertain. Note that the uncertainty is not an intrinsic property of the systems; it is the result of incomplete knowledge by the observer. The Aim of Geostatistics —The main objective of geostatistics is the characterization of spatial systems that are incompletely known, systems that are common in geology. A key difference from classical statistics is that geostatistics uses the sampling location of every measurement. Unless the measurements show spatial correlation, the application of geostatistics is pointless. Ordinarily the need for additional knowledge goes beyond a few points, which explains the display of results graphically as fishnet plots, block diagrams, and maps. Geostatistical Methods —Geostatistics is a collection of numerical techniques for the characterization of spatial attributes using primarily two tools: probabilistic models, which are used for spatial data in a manner similar to the way in which time-series analysis characterizes temporal data, or pattern recognition techniques. The probabilistic models are used as a way to handle uncertainty in results away from sampling locations, making a radical departure from alternative approaches like inverse distance estimation methods. Differences with Time Series —On dealing with time-series analysis, users frequently concentrate their attention on extrapolations for making forecasts. Although users of geostatistics may be interested in extrapolation, the methods work at their best interpolating. This simple difference has significant methodological implications. Historical Remarks —As a discipline, geostatistics was firmly established in the 1960s by the French engineer Georges Matheron, who was interested in the appraisal of ore reserves in mining. Geostatistics did not develop overnight. Like other disciplines, it has built on previous results, many of which were formulated with different objectives in various fields. Pioneers —Seminal ideas conceptually related to what today we call geostatistics or spatial statistics are found in the work of several pioneers, including: 1940s: A.N. Kolmogorov in turbulent flow and N. Wiener in stochastic processing; 1950s: D. Krige in mining; 1960s: B. Mathern in forestry and L.S. Gandin in meteorology Calculations —Serious applications of geostatistics require the use of digital computers. Although for most geostatistical techniques rudimentary implementation from scratch is fairly straightforward, coding programs from scratch is recommended only as part of a practice that may help users to gain a better grasp of the formulations. Software —For professional work, the reader should employ software packages that have been thoroughly tested to handle any sampling scheme, that run as efficiently as possible, and that offer graphic capabilities for the analysis and display of results. This primer employs primarily the package Stanford Geomodeling Software (SGeMS) - recently developed at the Energy Resources Engineering Department at Stanford University - as a way to show how to obtain results practically. This applied side of the primer should not be interpreted as the notes being a manual for the use of SGeMS. The main objective of the primer is to help the reader gain an understanding of the fundamental concepts and tools in geostatistics. Organization of the Primer —The chapters of greatest importance are those covering kriging and simulation. All other materials are peripheral and are included for better comprehension of these main geostatistical modeling tools. The choice of kriging versus simulation is often a big puzzle to the uninitiated, let alone the different variants of both of them. Chapters 14, 18, and 19 are intended to shed light on those subjects. The critical aspect of assessing and modeling spatial correlation is covered in chapter 7. Chapters 2 and 3 review relevant concepts in classical statistics. Course Objectives —This course offers stochastic solutions to common problems in the characterization of complex geological systems. At the end of the course, participants should have: an understanding of the theoretical foundations of geostatistics; a good grasp of its possibilities and limitations; and reasonable familiarity with the SGeMS software, thus opening the possibility of practically applying geostatistics.

Open-File Report↗
USGS2026

Production of mineral commodities and geospatial map of the mineral industries and related infrastructure of China

As part of the U.S. Geological Survey’s (USGS) mission to distribute global mineral information and analyze supply chains, this study provides a comprehensive review of the global significance of China’s mineral production and capacity in 2023. Of 77 mineral commodities in the USGS dataset, China produced 74 and was the world’s first-ranked producer for 39 of the 74. Compared to the high share of global mineral production, including up to 98 percent of global gallium production, the country’s share of global mineral reserves was relatively small, ranging from 20 percent (zinc ore) to 52 percent (tungsten ore). China’s imports of metal ores, slag, and ash accounted for 64 percent of global imports of such commodities by value. The country’s exports of base metals and articles of base metal accounted for 17 percent of the global exports. To help nongeographic information system users assess the spatial distribution of mineral mines, processing facilities, and ports for trades in China, this study created a geospatial (also called “georeferenced”) portable document format (GeoPDF) map. In addition, the GeoPDF contains mineral resource tracts (such as antimony, copper, potash, coal, and oil and gas), exploration sites, and energy infrastructure based on the preexisting USGS data.

Open-File Report↗
USGS1951

Carnotite resources of the upper group area, San Miguel County, Colorado

The Upper group area, which consists of 10 Government claims and adjoining public land, is 2 miles southeast of Slick Rock, San Miguel County, Colo., in unsurveyed secs. 5 and 6, T. 43 N., R. 18 W., New Mexico principal meridian. The area is equidistant from mills at Monticello, Utah, and Naturita, Colo. Both mills are reached by about 45 miles of all-weather roads. About 2,700 tons of carnotite ore was produced from the area between 1921 and 1943 (tons used in this report are short tons). This ore had an estimated average grade of 0.25 percent U30g and 1.7 percent V205. The ore deposits are in the top sandstone stratum of the Salt Wash sandstone member of the Tipper Jurassic Morrison formation. The principal ore-bearing minerals, which mainly impregnate the sandstone, consist of uranium-bearing carnotite and a micaceous vanadium-bearing mineral called “roscoelite." The deposits are mostly in small podlike masses called "rolls." The size of the rolls ranges from less than 50 to more than 1,500 tons each. The long axes of the rolls have a dominant northeasterly to easterly trend. Exploration by the Geological Survey was done on behalf of the Atomic Energy Commission to test unexplored ground for new deposits of carnotite ore and to gain a better appraisal of the reserves in the area. From 1948 to 1950, 186 diamond-drill holes were completed for a total of 14,577 feet. The areas of favorable sandstone were found and defined by holes drilled 300 to 500 feet apart. Altered mudstone, carbonaceous material in the sandstone, and color of the sandstone were used to determine the favorability of the sandstone. Within areas containing favorable sandstone holes were drilled on 100- to 150-foot centers to find deposits. Where deposits were found more than 20 feet below the surface, they were roughly outlined by holes drilled on 50- to 75- foot centers. Deposits discovered within 20 feet of the surface were not outlined. Reserves in deposits found by the drilling are classed as indicated and inferred, whereas those reserves that are predicted solely on geologic evidence are classed as potential. Indicated reserves computed at the highest thickness and grade cut-offs (1 foot or more thick and 0.10 percent U3O8 or .10 percent V205) total 5,000 tons, averaging 0.19 percent U308 and 1.6 percent V205. Inferred reserves computed at the same cut-offs total 3,500 tons, averaging .22 percent U308 and 1.7 percent V205. Both the indicated and inferred reserves, as well as the pounds of contained U3O8and V205, are summarized in table 1. Potential reserves are predicted to total about 1,500 tons, averaging about 0.20 percent U3O8 and 1.6 percent V205. Most of the potential reserves are expected to be in small scattered deposits within 20 feet of the surface. No additional diamond drilling by the Geological Survey is planned in the Upper group area. Several specific localities, principally in the central part of the area, are recommended for further exploration by jackhammer and wagon drilling by lessees and operators.

Colorado↗
USGS2014

Sandstone copper assessment of the Teniz Basin, Kazakhstan

The U.S. Geological Survey (USGS) conducts national and global resource assessments (mineral, energy, water, and biological) to provide data and scientific analyses to support decision making. Three-part mineral resource assessments result in informed, unbiased, quantitative, and probabilistic estimates of undiscovered mineral resources and deposits. In particular, mineral assessment results inform decisions concerning land-use and mineral-resource development. A probabilistic mineral resource assessment of the sandstone subtype of sediment-hosted stratabound copper deposits in the Teniz Basin, Kazakhstan, was undertaken by the USGS. The Teniz Basin is located in Akmola Oblast, central and western Kazakhstan. With an areal extent of almost 78,000 km 2 , the basin contains many sediment-hosted stratabound copper prospects, none of which are well described, and the majority of which may belong to the sandstone subtype of sediment-hosted copper deposits. There are no known locations within the Teniz Basin currently mined for copper. Within the basin, however, map units permissive for the sandstone subtype of sediment-hosted stratabound copper deposits include (from oldest to youngest): the Middle Carboniferous Kiery Suite; the Middle to Upper Carboniferous Vladimirov Suite (a stratigraphic equivalent of the Dzhezkazgan Suite, Chu-Sarysu Basin); and the Upper Carboniferous or lowest Permian Kayraktin Suite. The multicolored sedimentary rocks of the Vladimirov Suite, in which 14 potentially ore-bearing horizons of gray beds have been recorded, have the greatest potential for undiscovered, sandstone subtype, sediment-hosted stratabound copper deposits. A quantitative mineral resource assessment has been completed that (1) delineates one 49,714 km 2 tract permissive for undiscovered, sandstone subtype, sediment-hosted stratabound copper deposits, and (2) provides probabilistic estimates of numbers of undiscovered deposits and probable amounts of copper resource contained in those deposits. The permissive tract delineated in this assessment encompasses no previously known sandstone subtype, sediment-hosted stratabound copper deposits. However, this assessment estimates (with 30 percent probability) that a mean of nine undiscovered sandstone subtype copper deposits may be present in the Teniz Basin and could contain a mean total of 8.9 million metric tons of copper and 7,500 metric tons of silver.

Teniz Basin↗
USGS2017

Environmental considerations related to mining of nonfuel minerals

Throughout most of human history, environmental stewardship during mining has not been a priority partly because of the lack of applicable laws and regulations and partly because of ignorance about the effects that mining can have on the environment. In the United States, the National Environmental Policy Act of 1969, in conjunction with related laws, codified a more modern approach to mining, including the responsibility for environmental stewardship, and provided a framework for incorporating environmental protection into mine planning. Today, similar frameworks are in place in the other developed countries of the world, and international mining companies generally follow similar procedures wherever they work in the world. The regulatory guidance has fostered an international effort among all stakeholders to identify best practices for environmental stewardship. The modern approach to mining using best practices involves the following: (a) establishment of a pre-mining baseline from which to monitor environmental effects during mining and help establish geologically reasonable closure goals; (b) identification of environmental risks related to mining through standardized approaches; and (c) formulation of an environmental closure plan before the start of mining. A key aspect of identifying the environmental risks and mitigating those risks is understanding how the risks vary from one deposit type to another—a concept that forms the basis for geoenvironmental mineral-deposit models. Accompanying the quest for best practices is the goal of making mining sustainable into the future. Sustainable mine development is generally considered to be development that meets the needs of the present generation without compromising the ability of future generations to meet their own needs. The concept extends beyond the availability of nonrenewable mineral commodities and includes the environmental and social effects of mine development. Global population growth, meanwhile, has decreased the percentage of inhabitable land available to support society’s material needs. Presently, the land area available to supply the mineral resources, energy resources, water, food, shelter, and waste disposal needs of all Earth’s inhabitants is estimated to be 135 square meters per person. Continued global population growth will only increase the challenges of sustainable mining. Current trends in mining are also expected to lead to new environmental challenges in the future, among which are mine-waste management issues related to mining larger deposits for lower ore grade; water-management issues related to both the mining of larger deposits and the changes in precipitation brought about by climate change; and greenhouse gas issues related to reducing the carbon footprint of larger, more energy-intensive mining operations.

Professional Paper↗
USGS1979

Ground-water quality in Bannock, Bear Lake, Caribou, and part of Power counties, southeastern Idaho

This report provides information about the current quality of ground waters in southeastern Idaho and discusses the natural and manmade environmental controls on that quality. This information will be useful in planning and monitoring the development and use of the ground-water resources of southeastern Idaho. The southeastern corner of Idaho, as described in this report, encompasses an area of about 4,000 mil in Bannock, Bear Lake, Caribou, and part of Power Counties. The popu- lation of the area in 1975, based on best estimates by the Idaho Division of Budget, Policy Planning, and Coordination (1976) was 75,200. About 80 percent of the population is in and near the city of Pocatello, which is the second largest population center in the State. Pocatello's economy depends largely on manufacturing and industrial processing, which includes chemicalfertilizer plants. The econ- omy in the rural areas depends largely on agriculture--both dry and irrigated farming are practiced. Mining is important and expected to dominate the economy in the eastcentral part of the area in the future. Natural resources include phosphate ore, which makes up about 35 percent of the U.S. reserves (U.S. Department of Interior and U.S. Department of Agriculture, 1977); ground water, which mostly underlies the several intermontane valleys that dissect the area; and hot springs, which indicate that geothermal energy sources may underlie part of the area. Also, current (1978) speculation is that petroleum reserves may be present in the vicinity of Bear Lake. Development of more sprink- ler-irrigated lands, increases in population, and growth of phosphate mining are expected to place stress on the ground-water resources, both in quality and quantity. The purpose of this report is to present the results of a study whose primary objectives were (1) to provide current waterquality data representative of the water in several different aquifers (water- bearing formations) in the study area, and (2) to relate these data to natural and manmade environmental controls. The wells sampled during this study establish a quasi-network, which could be resampled in the future to document and analyze changes (if any) in ground-water quality. Based on this information, planners and water managers could better understand the causeand-effect relations controlling water quality and could better manage land and water-resource development. The report is designed for ease of reading and presentation. It uses maps, tables, and abbreviated text to describe geology, hydrology, and ground-water quality and how they are interrelated. Some practical ways for improving water quality are discussed for the benefit of individual water users. The field data collected in making the study are contained in the Data Section of this report. The authors gratefully acknowledge the many individual well owners, municipal officials, and private industries that provided well information and allowed access to their properties and collection of water samples. Without their help, this work could not have been done. Water samples were collected at 103 well sites. Waterlevel measurements were made at 98 of these sites during July, August, and September of 1976. This study was made by the U.S. Geological Survey in cooperation with the Idaho Department of Water Resources. A similar study is being made (1978) in north Idaho. Other studies are planned, specifically to obtain ground-water-quality data in areas where land and water-resource development is expected or accelerating.

Idaho↗
USGS1956

Non-pegmatitic resources of beryllium in United States

During the period from 1948 to 1950 the U.S. Geological Survey conducted a program of field and laboratory research w determine the mode of occurrence of beryllium in non-pegmatitic rocks and mineral deposits as part of the Beryllium Program of the Division of Raw Materials of the U.S. Atomic Energy Commission. Approximately 23 man months were spent in the field collecting samples from 146 localities in 15 states; a total of 680 samples were collected and analyzed for beryllium. Additional samples collected by the Geological Survey. U.S. Bureau of Mines, various state Geological Surveys and other institutions. and private companies were analyzed for beryllium. In total, the beryllium content of 1,238 samples from about 600 localities in the United States is compiled in the final report which is being prepared for publication by the U.S. Geological Survey. The main topics discussed are: uses and properties of beryllium; methods of analysis and mineralogy of beryllium; occurrence of beryllium in igneous, sedimentary and metamorphic rocks, pyrometasomatic and related deposits, vein deposits, and hot spring deposits; the genesis of beryllium deposits; and a description of the deposits examined. This abstract and table 1 summarize the more pertinent economic data. Beryllium is more abundant than arsenic, gold, silver, and molybdenum in the lithosphere, but its chemical and physical properties prohibit its concentration in minerals which are common w large commercial vein and replacement deposits. There are 29 minerals in which beryllium is an essential constituent but of these only beryl, mined from granite pegmatites, is an ore of beryllium., Beryl also occurs disseminated in granites and high-temperature veins. The other 28 minerals occur as rare constituents in syenite and granite pegmatites, granites, and pyrometasomatic deposits. Beryllium, as a trace constituent, has been detected in 49 minerals but recovery of the beryllium requires metallurgical methods as yet unknown.

Trace Elements Investigations↗
USGS2011

Porphyry copper assessment of British Columbia and Yukon Territory, Canada: Chapter C in Global mineral resource assessment

The U.S. Geological Survey does regional, national, and global assessments of resources (mineral, energy, water, biologic) to provide science in support of land management and decision making. Mineral resource assessments provide a synthesis of available information about where mineral deposits are known and suspected to be in the Earth’s crust, which commodities may be present, and estimates of amounts of resources that may be present in undiscovered deposits. Canada is an important source of copper, consistently ranking as one of the top 10 world producers during the past decade (2000–2010). The preponderance of this production has been from porphyry-copper-type deposits in the western Canadian Cordillera. A probabilistic mineral resource assessment of undiscovered resources associated with porphyry copper deposits in western Canada was completed as part of a global mineral resource assessment. The purpose of the assessment was to (1) compile a database of known deposits and significant prospects, (2) delineate permissive areas (tracts) for undiscovered porphyry copper deposits that may be present in the upper kilometer (minimally) of the Earth’s crust, and (3) provide probabilistic estimates of amounts of copper (Cu), molybdenum (Mo), gold (Au), and silver (Ag) that could be contained in undiscovered porphyry copper deposits in the tracts. The study was done by the U.S. Geological Survey (USGS) in collaboration with geologists from the British Columbia Geological Survey, Yukon Geological Survey, and industry consultants. The database of known deposits and significant prospects includes an inventory of mineral resources in 89 known porphyry copper (and 2 related copper-bearing polymetallic vein) ore zones, representing 50 porphyry copper deposits, and lists key characteristics of 280 additional porphyry copper and related copper-bearing prospects, as indicated by currently available exploration results, which also are summarized. Resource and exploration and development activity are updated with information current through April 2010. The delineation of permissive tracts and probabilistic estimation of resources in undiscovered deposits were done using the USGS three-part mineral resource assessment approach. Permissive tracts are defined in accordance with descriptive models for porphyry copper deposits to include igneous rocks and known deposits and prospects within magmatic arcs related to convergent plate-margin boundary zones. Frequency distributions of total tonnages and average grades of thoroughly explored deposits were used as models for undiscovered deposits and include a new grade and tonnage model for calc-alkaline porphyry Cu±Mo±Au deposits in western Canada. Five permissive tracts for the occurrence of porphyry copper deposits were delineated: 2 island-arc tracts, 1 tract of transitional, mixed island-arc and continental arc affinities, and 2 continental arc tracts. In permissive tract 003pCu2001, calc-alkaline igneous rocks of Middle Triassic to Late Jurassic age in accreted island-arc terranes of the Intermontane belt are assessed for calc-alkaline porphyry Cu±Mo±Au deposits. The area of this tract is 175,250 km 2 . In 12 known deposits, the total reported tonnage of ore is 8,100 million metric tons (Mt) containing 24.6 Mt copper. An estimated 6.9 undiscovered deposits contain a calculated mean of 8.9 Mt copper and a median of 6.9 Mt copper. The spatial density for the 18.9 known plus estimated undiscovered deposits in this tract is approximately 11 deposits per 100,000 km 2 . In permissive tract 003pCu2002, alkaline igneous rocks of Middle Triassic to Late Jurassic age within the Intermontane accreted island-arc terranes are assessed for alkaline porphyry Cu-Au deposits. The area of this tract is 109,290 km 2 . In 12 known deposits the total reported tonnage of ore is 6,440 Mt, containing 20.9 Mt copper. An estimated 7 undiscovered deposits contain a calculated mean of 22 Mt copper and a median of 13 Mt copper. The spatial density for the 19 known plus estimated undiscovered deposits in this tract is approximately 17 deposits per 100,000 km 2 . In permissive tract 003pCu2003, calc-alkaline igneous rocks of Late Triassic to Early Cretaceous age within the accreted Insular terranes of mixed island-arc and continental arc affinities are assessed for calc-alkaline porphyry Cu±Mo±Au deposits. The area of this tract is 58,360 km 2 . The total tonnage of ore reported in the 2 known deposits is 1,160 Mt containing 3.17 Mt copper. An estimated 2.3 undiscovered deposits contain a calculated mean of 3 Mt copper and a median of 1.9 Mt copper. The spatial density for the 4.3 known plus estimated undiscovered deposits in this tract is approximately 7 deposits per 100,000 km 2 . In permissive tract 003pCu2004, calc-alkaline igneous rocks in continental magmatic arcs of Jurassic to Eocene age are assessed for porphyry Cu±Mo±Au deposits. The area of this tract is 639,500 km 2 . The total tonnage of ore reported for the 23 known deposits is 6,520 Mt containing 17.9 Mt copper. An estimated 9.6 undiscovered deposits contain a calculated mean of 13 Mt copper and a median of 11 Mt copper. The spatial density for the 32.6 known deposits plus the estimated undiscovered deposits in this tract is approximately 5 deposits per 100,000 km 2 . In permissive tract 003pCu2005, calc-alkaline igneous rocks in continental magmatic arcs of Oligocene to Pliocene age are assessed for porphyry Cu±Mo±Au deposits. The area of this tract is 32,840 km 2 . The total tonnage of ore reported for the 1 known deposit is 44.8 Mt containing 0.224 Mt copper. An estimated 1.4 undiscovered deposits contain a calculated mean of 1.8 Mt copper and a median of 0.72 Mt copper. The spatial density for the 2.4 known plus estimated undiscovered deposits in this permissive tract is approximately 7 deposits per 100,000 km 2 . Western Canada has been thoroughly explored for porphyry copper deposits. The total estimated copper contained in known deposits is about 66.8 Mt (based on 2010 data), as compared to a 49 Mt mean of estimated copper in undiscovered deposits and a 34 Mt median of estimated copper in undiscovered deposits. The copper contained in known porphyry copper deposits represents about 58 percent of the total of known and undiscovered porphyry copper deposits (based on mean values). About 86 percent of the increase in estimated copper resources between 1993 and 2009 resulted from the discovery of extensions to known deposits. Nevertheless, exploration for undiscovered deposits continues, especially in and around significant prospects and in parts of permissive tracts that are mostly hidden beneath younger volcanic, sedimentary, or vegetated surficial cover.

British Columbia, Yukon Territory↗
USGS1976

Discovery of natural resources

Mankind will continue to need ores of more or less the types and grades used today to supply its needs for new mineral raw materials, at least until fusion or some other relatively cheap, inexhaustible energy source is developed. Most deposits being mined today were exposed at the surface or found by relatively simple geophysical or other prospecting techniques, but many of these will be depleted in the foreseeable future. The discovery of deeper or less obvious deposits to replace them will require the conjunction of science and technology to deduce the laws that governed the concentration of elements into ores and to detect and evaluate the evidence of their whereabouts. Great theoretical advances are being made to explain the origins of ore deposits and understand the general reasons for their localization. These advances have unquestionable value for exploration. Even a large deposit is, however, very small, and, with few exceptions, it was formed under conditions that have long since ceased to exist. The explorationist must suppress a great deal of "noise" to read and interpret correctly the "signals" that can define targets and guide the drilling required to find it. Is enough being done to ensure the long-term availability of mineral raw materials? The answer is probably no, in view of the expanding consumption and the difficulty of finding new deposits, but ingenuity, persistence, and continued development of new methods and tools to add to those already at hand should put off the day of "doing without" for many years. The possibility of resource exhaustion, especially in view of the long and increasing lead time needed to carry out basic field and laboratory studies in geology, geophysics, and geochemistry and to synthesize and analyze the information gained from them counsels against any letting down of our guard, however (17). Research and exploration by government, academia, and industry must be supported and encouraged; we cannot wait until an eleventh hour to mount a "crash program.".

Science↗
USGS1983

Mineral resource potential map of the Blanco Mountain and Black Canyon Roadless Areas, Inyo and Mono Counties, California

On the basis of geologic, geochemical, and geophysical investigations and a survey of mines and prospects, the mineral resource potential for gold, silver, lead, zinc, tungsten, and barite of the Blanco Mountain and Black Canyon Roadless Areas is judged to be low to moderate, except for one local area that has high potential for gold and tungsten resources. A geochemical survey detected moderately anomalous amounts of lead, copper, and zinc and less anomalous concentrations of tungsten, gold, and silver. Elements in anomalous samples were grouped as suites known to form in various ore deposits. Four element suites that may be indicative of mineralization are recognized in the White Mountains: (1) lead, zinc, and silver in carbonate rocks; (2) copper, barite, and lead in veins and replacement bodies; (3) tungsten, molybdenum, and bismuth in skarns; and (4) gold and arsenic in mineralized quartz veins. The assessment of the areas of resource potential was made in part by the application of ore deposit models to the geochemical results. A mineral deposit survey by the U.S. Bureau of Mines indicates that there are no properties with identified mineral resources in the Blanco Mountain Roadless Area. There is one active placer claim. In the Black Canyon Roadless Area, two properties have 40,000 tons of indicated and inferred low-grade gold, silver, or lead-bearing rock. Five properties near this roadless area have 150,000 tons of indicated and inferred low-grade gold, silver, lead, zinc, or tungsten-bearing rock. About 90 percent of this tonnage is estimated to occur at the Mirage-Mariposa and the Hope mines. The roadless areas have no known resource potential for geothermal energy, coal, oil, or gas.

California↗
USGS2016

Recent trends in the nonfuel minerals industry of Iran

Summary In response to the recent removal of international sanctions on Iran, including the lifting of “secondary” sanctions by the United States on investment into and trade with Iran, the U.S. Geological Survey National Minerals Information Center compiled and analyzed available information on the current state of Iran’s nonfuel minerals industry. This Circular features a new map and table that identify existing mines and mineral-processing facilities and provide information on location, ownership, and capacity for metals and industrial minerals whose output levels may substantially change in the near future. Additionally, the report covers Iran’s mineral resources and reserves, official mineral production targets for 2025, and current output and share of global mineral production. Recent trends and developments in individual mineral commodities are discussed, including mineral exploration and partnerships with foreign investors. The U.S. Geological Survey estimated that Iran held globally significant reserves of feldspar (2d largest in the world), barite (5th largest), gypsum (5th largest), fluorspar (8th largest), and iron ore (10th largest). The Government of Iran claimed to also have significant reserves of chromium, copper, gold, manganese, phosphate rock, and zinc. In 2014, Iran was the second-leading producer of gypsum and the sixth-leading producer of barite, with 6.1 percent and 3.6 percent of world output, respectively. Iran was also the world’s 7th-leading producer of cement, feldspar, and fluorspar; 8th-leading producer of bentonite; 9th-leading producer of molybdenum; 11th-leading producer of iron ore; and 14th-leading producer of crude steel. The Government of Iran plans to quadruple the output of aluminum, copper cathode, direct-reduced iron, and iron ore pellets; triple that of crude steel and gold; and double that of cement, pig iron, and zinc by 2025. It also plans to double the contribution of mining and to quadruple that of mineral processing to the national economy in the next decade. In order to achieve these major goals, the construction and expansion of several mines and mineral facilities are planned or under development. Whether Iran’s annual mineral production increases as rapidly as envisioned by the Government will depend largely on the amount of foreign investment into the minerals industry; integration of modern technology into mineral facilities; and availability of energy to aluminum, copper, and steel plants at competitive prices to international investors.

Circular↗
USGS2025

A time-space model of graphite mineral systems

Increasing demand for graphite in energy storage systems warrants review of graphite ore genesis in a mineral systems framework. Orogenic graphite encompasses the metamorphic and orogenic mineral systems that produce flake graphite and hydrothermal vein (lump and chip) graphite deposits, respectively. A common feature of orogenic graphite deposits is an association with upper amphibolite- to granulite-facies metasedimentary rocks in continent-continent or continent-island arc collisional orogens. Orogenic flake graphite deposits form primarily through graphitization of organic carbon during regional metamorphism, but strain localization and partial melting of pelitic protoliths are likely important processes for graphite grade and quality enrichment. Orogenic vein graphite deposits precipitate from hydrothermal fluids, possibly derived from metamorphism or anatexis at depth. Decarbonation reactions in mixed calcareous-carbonaceous metasedimentary sequences are the most likely carbon sources for the veins. In contrast, intrusion-related graphite includes magmatic-hydrothermal and metamorphic mineral systems that form primarily in continental arc settings via the interaction of magmas with carbonaceous sedimentary packages. Magmatic-hydrothermal flake graphite deposits are hosted in plutonic and volcanic rocks, and result from the exsolution of CO 2 -CH 4 -rich fluids from melts contaminated by such packages. Contact metamorphism of carbonaceous sedimentary rocks by plutons produces some microcrystalline (amorphous) graphite deposits, including many in China. Compilation of geologic data from known graphite deposits globally suggests that pulses of carbon deposition in the Paleoproterozoic, Mesoproterozoic, and Neoproterozoic provided source carbon material. Subsequent supercontinent orogenesis at ca. 2,100 to 1,700 Ma (Columbia), ca. 1,300 to 1,000 Ma (Rodinia), and ca. 650 to 500 Ma (Gondwana) resulted in the genesis of orogenic flake and vein graphite deposits, where favorable geologic components overlapped with organic ± carbonate carbon-rich strata. Cryogenian deposition of graphite protoliths and Cryogenian – Cambrian metamorphic mineralization account for nearly 75% of all known resources globally and coincide with profound carbon isotope excursions and climate variability, implying a link with the global carbon budget. Comparatively few graphite deposits are associated with Pangea-forming orogens, attributed to less exhumation and/or denudation. High-temperature metasedimentary belts containing organic carbon-rich protoliths are most favorable for hosting orogenic flake graphite deposits, whereas sequences that also contain carbonate protoliths are favorable for orogenic graphite veins. Continent-scale orogenic belts may host both deposit types along with vanadium deposits. Use of a time-space mineral systems framework for graphite deposits can improve exploration models needed to ensure future supply of this critical mineral and provide insights into Earth’s long-term carbon cycle.

Mineralium Deposita↗
USGS2024

Energy-related rare earth element sources

Energy-related materials such as coal, coal-bearing wastes, and coal combustion products are traditionally thought of as sources or by-products of electric power generation. Increasingly, these materials are considered resources for their content of rare earth elements (REEs) and other useful constituents. In this chapter, we examine the distribution, modes of occurrence, and relative extractability of REEs from coal-derived materials. We also consider economic factors associated with recovery of REEs from these sources. While several coal-derived sources show promise for REE recovery at the pilot scale, in all cases, REE contents are much below those of primary ores, such that extraction and concentrating the REEs require new and innovative approaches that are largely developmental. Among coal-related sources, fly ash is the most REE-enriched, as REEs from coal are strongly retained in these refractory solids remaining after coal combustion. Partitioning of coal-derived elements into fly ash has been known for decades but this has yet to be commercially exploited. A key drawback shown in this chapter is that a significant fraction of REEs in fly ash is contained in highly insoluble aluminosilicate glasses that make up the largest portion of this material. In addition to testing chemical or physical pretreatment approaches to help improve the extractability of REEs from fly ash, current research is applying modern analytical approaches to better understand the distribution of REEs on increasingly smaller scales, in the interest of targeting their recovery. Next-most REE-enriched among coal-related materials are solid waste products of coal mining and wastes from coal preparation, both of which are REE-enriched relative to coal itself. These waste coals concentrate mineralogical constituents that are excluded during mining or removed during coal preparation because they do not contribute to the heating value of coal for power generation. Recovery of REEs from coal waste has shown promise at the pilot scale and has the added benefit of converting a waste into useful constituents. Total REE contents of commercial coals are, on average, much below the 300 parts per million interest level for REE recovery set by the U.S. Department of Energy (DOE). However, as reviewed in this chapter, certain horizons within coal beds show preferential REE enrichment and could be targeted by selective mining. Beyond this, certain coals are REE-enriched overall due to their unique geologic histories involving derivation from REE-enriched sediment sources, deposition of volcanic ash during coal formation, or interaction of coal with REE-bearing fluids. Acidic drainage from abandoned coal mines is produced by the breakdown of pyrite (FeS 2 ), which is unstable in oxygenated conditions. While these acidic fluids have lower REE contents than any of the coal-based solids described above, they are proportionally enriched in certain heavy rare earths, especially yttrium (Y). Precipitates from coal-based acid-mine drainage concentrate REEs to levels that are of interest for recovery, and these are also promising sources for extraction at the pilot scale.

Book chapter↗
USGS1973

Geology and mineral resources of central Antioquia Department (Zone IIA), Colombia

This report summarizes the geology of an area of some 6000 square kilometers in the northern part of the Central Cordillera of the Colombian Andes. The area, in north-central Department of Antioquia, was mapped between 1964 and 1968 as part of the Inventario Minero Nacional (IMN) project. Mineral resources are summarized within a larger area, designated as subzone ILK of IMN Zone If, which comprises almost 22,000 sq. kin, including the area mapped geologically by IMN and additional areas mapped by other agencies. The oldest formation is a micaceous paragneiss of early Paleozoic or possibly late Precambrian age. A thick geosynclinal sedimentary series accumulated during the Paleozoic Era and became regionally metamorphosed to greenschist (locally amphibolite) facies during the Permian or early Triassic; these schists and gneisses are designated collectively as the Valdivia Group. The Permian(?) orogenic episode included intrusion of concordant syntectonic plutons, mostly of tonalitic composition. Rocks of unequivocal Triassic or Jurassic age are not recognized. The Cretaceous is well represented by both igneous and sedimentary assemblages. Eugeosynclinal alpine ophiolites comprising submarine basalt flows and numerous intrusions of gabbro and serpentinite are prominent in the Lower Cretaceous, together with flysch composed of marine shale and lesser sandstone and conglomerate. The Upper Cretaceous is represented along the west border of the mapped area by submarine basalt flows and pyroclastic rocks, locally Interbedded with fine-grained clastic sedimentary beds, and lenses of dark laminated chert, at least part of which is radiolarian. The Late Cretaceous was marked by an orogenic event that profoundly folded and faulted all rocks and in the Central Cordillera caused low-grade metamorphism, the overprint of which is hardly observable in pre-Cretaceous rocks elsewhere. The Late Cretaceous orogeny culminated with discordant intrusion of the epizonal tonalitic Antioquian batholith. Displacement along the great Romeral wrench fault may have begun in the Cretaceous. Plutonism continued into the Cenozoic, exemplified by the hornblende-diorite Sabanalarga pluton. Intermontane basins were filled with molasse derived from the erosion of adjacent highlands; Tertiary sedimentation in marshy areas included organic carboniferous matter subsequently converted to lignite or subbituminous coal. The Sabanalarga fault system originated in the Late Tertiary; intermittent displacement continued on the older wrench faults such as the Romeral. Epeirogenic uplift, which probably began in the Pliocene and continued through the Pleistocene and Holocene, brought on renewed erosion which has sculptured the mountains into their present form. Mineral resources in subzone IIA are varied but not of outstanding importance. Gold and silver mining, significant in past centuries, is minor today. Ferruginous laterite on serpentinite once considered as a potential source of iron ore is not economically exploitable. IMN has explored nickeliferous laterite at the extreme northwest corner of subzone IIA; this is a potential resource, exploitable only after exhaustion of the larger and richer nickel laterite deposit at Cerro Matoso, farther to the north and outside the boundaries of Zone If. Known deposits of mercury, chromium, manganese, and copper are small, with limited economic potential. Nonmetallic resources include raw materials for cement, including portland cement. Saprolite clay is widely used in making common red brick and tile, still a dominant construction material in all but the most modern multistory buildings. Aggregate materials are varied and abundant. Kaolin of good quality near La Union is important as a ceramic raw mineral filler. Tertiary subbituminous coal beds are an important energy resource in western subzone IIA, and have a good potential for greater development. Deposits of sodic feldspar, talc, decorative stone, and silica a

Open-File Report↗