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At least 1,189 records · Page 66Linked to original sources

USGS1972

Cenozoic rocks of the Santa Rita Mountains, southeast of Tucson, Arizona

The Santa Rita Mountains of southeastern Arizona are underlain, in part, by volcanic and sedimentary rocks and by many small intrusives, of Cenozoic age. These rocks provide a more complete geologic record than that of other ranges in the region, and consequently the Santa Rita Mountains are a useful reference area from which to develop the Cenozoic geologic history of the region. Many isotopic ages provide the basis for dating key units and add to the confidence in the interpretations of the geologic record of the rocks themselves. The rocks of the greatest potential economic interest are the Greaterville intrusives of the Helvetia and Greaterville mining districts and the quartz vein swarm of the Tyndall and Wrightson mining districts.

Arizona↗

USGS2005

Monitoring-well network and sampling design for ground-water quality, Wind River Indian Reservation, Wyoming

The Wind River Indian Reservation, located in parts of Fremont and Hot Springs Counties, Wyoming, has a total land area of more than 3,500 square miles. Ground water on the Wind River Indian Reservation is a valuable resource for Shoshone and Northern Arapahoe tribal members and others who live on the Reservation. There are many types of land uses on the Reservation that have the potential to affect the quality of ground-water resources. Urban areas, rural housing developments, agricultural lands, landfills, oil and natural gas fields, mining, and pipeline utility corridors all have the potential to affect ground-water quality. A cooperative study was developed between the U.S. Geological Survey and the Wind River Environmental Quality Commission to identify areas of the Reservation that have the highest potential for ground-water contamination and develop a comprehensive plan to monitor these areas. An arithmetic overlay model for the Wind River Indian Reservation was created using seven geographic information system data layers representing factors with varying potential to affect ground-water quality. The data layers used were: the National Land Cover Dataset, water well density, aquifer sensitivity, oil and natural gas fields and petroleum pipelines, sites with potential contaminant sources, sites that are known to have ground-water contamination, and National Pollutant Discharge Elimination System sites. A prioritization map for monitoring ground-water quality on the Reservation was created using the model. The prioritization map ranks the priority for monitoring ground-water quality in different areas of the Reservation as low, medium, or high. To help minimize bias in selecting sites for a monitoring well network, an automated stratified random site-selection approach was used to select 30 sites for ground-water quality monitoring within the high priority areas. In addition, the study also provided a sampling design for constituents to be monitored, sampling frequency, and a simple water-table level observation well network.

Scientific Investigations Report↗

USGS2007

Quality of Selected Hungarian Coals

As part of a program conducted jointly by the U.S. Geological Survey and the Hungarian Geological Survey under the auspices of the United States-Hungarian Science and Technology Fund, a total of 39 samples from five coal mines in Hungary were selected for analysis. The mine areas sampled represent most of the coal mined recently in Hungary. Almost all the coal is used to generate electricity. Coals from the five mines (four underground, one surface) reflect differences in age, depositional setting, organic and inorganic components of the original sediments, and deformational history. Classified according to the ranking system of the American Society for Testing and Materials, the coals range in rank from lignite B (Pliocene[?] coals) to high volatile A bituminous (Jurassic coals). With respect to grade classification, based on seam-weighted averages of moisture, ash, and sulfur contents: (1) all contain high moisture (more than 10 percent), (2) all except the Eocene coals are high (more than 15 percent) in ash yield, and (3) two (Jurassic and Eocene coals) are high in sulfur (more than 3 percent) and three (Cretaceous, Miocene, and Pliocene coals) have medium sulfur contents (1 to 3 percent). Average heat values range from 4,000 to 8,650 British thermal units per pound.

Scientific Investigations Report↗

USGS2013

Zirconium

Zirconium is the 20th most abundant element in the Earth’s crust. It occurs in a variety of rock types and geologic environments but most often in igneous rocks in the form of zircon (ZrSiO 4 ). Zircon is recovered as a coproduct of the mining and processing of heavy mineral sands for the titanium minerals ilmenite and rutile. The sands are formed by the weathering and erosion of rock containing zircon and titanium heavy minerals and their subsequent concentration in sedimentary systems, particularly in coastal environments. A small quantity of zirconium, less than 10 kt/a (11,000 stpy), compared with total world production of 1.4 Mt (1.5 million st) in 2012, was derived from the mineral baddeleyite (ZrO 2 ), produced from a single source in Kovdor, Russia.

Mining Engineering↗

USGS2016

Manganese nodules

The existence of manganese (Mn) nodules (Figure 1) has been known since the late 1800s when they were collected during the Challenger expedition of 1873–1876. However, it was not until after WWII that nodules were further studied in detail for their ability to adsorb metals from seawater. Many of the early studies did not distinguish Mn nodules from Mn crusts. Economic interest in Mn nodules began in the late 1950s and early 1960s when John Mero finished his Ph.D. thesis on this subject, which was published in the journal Economic Geology (Mero, 1962) and later as a book (Mero, 1965). By the mid-1970s, large consortia had formed to search for and mine Mn nodules that occur between the Clarion and Clipperton fracture zones (CCZ) in the NE Pacific (Figure 2). This is still the area considered of greatest economic potential in the global ocean because of high nickel (Ni), copper (Cu), and Mn contents and the dense distribution of nodules in the area. While the mining of nodules was fully expected to begin in the late 1970s or early 1980s, this never occurred due to a downturn in the price of metals on the global market. Since then, many research cruises have been undertaken to study the CCZ nodules, and now 15 contracts for exploration sites have been given or are pending by the International Seabed Authority (ISA). Many books and science journal articles have been published summarizing the early work (e.g., Baturin, 1988; Halbach et al., 1988), and research has continued to the present day (e.g., ISA, 1999; ISA, 2010). Although the initial attraction for nodules was their high Ni, Cu, and Mn contents, subsequent work has shown that nodules host large quantities of other critical metals needed for high-tech, green-tech, and energy applications (Hein et al., 2013; Hein and Koschinsky, 2014).

Book chapter↗

USGS2022

Development and description of a composite hydrogeologic framework for inclusion in a geoenvironmental assessment of undiscovered uranium resources in Pliocene- to Pleistocene-age geologic units of the Texas Coastal Plain

A previously completed mineral resources assessment of the Texas Coastal Plain indicated the potential for the future discovery of uranium resources. Geoenvironmental assessments that include the hydrogeologic framework can be used as a tool to understand the potential effects of mining operations. The hydrogeologic framework for this study focused on the composite hydrogeologic unit of the tract permissive for the occurrence of uranium consisting of the upper part of the Miocene-age Fleming Formation/Lagarto Clay, Pliocene-age Goliad and Pleistocene-age Willis Sands, Pleistocene-age Lissie and Beaumont Formations, and Holocene-age alluvial sediments (fluvial alluvium and eolian sand deposits). This composite hydrogeologic unit, which contains the Chicot and Evangeline aquifers of the Gulf Coast aquifer system, is intended for inclusion in a regional-scale geoenvironmental assessment of as yet undiscovered uranium resources. This article provides (1) a brief literature review describing the geologic and hydrogeologic settings, (2) the methodology used to develop a composite hydrogeologic framework, and (3) descriptions and maps of the land-surface altitude, composite hydrogeologic unit base and midpoint depth, water-level altitude, depth of water, unsaturated and saturated zone thickness, and transmissivity and hydraulic conductivity. A composite hydrogeologic unit, created by combining geologic and hydrogeologic data and maps for individual geologic and hydrogeologic units, is intended for use as a tool in a geoenvironmental assessment to evaluate potential contaminant migration through various avenues. Potential applications include using the hydrogeologic framework as an input into a geoenvironmental assessment to help estimate the potential for (1) runoff of contaminants into surface water, (2) infiltration of contaminants into the groundwater (aquifers), or (3) movement of contaminants from the mining area through wind, groundwater-flow, or streamflow in a given permissive tract. The procedures outlined in this paper also provide a method for developing hydrogeologic frameworks that can be applied in other areas where mining may occur.

Texas↗

USGS2015

Frac sand in the United States: a geological and industry overview

A new mineral rush is underway in the upper Midwest of the United States, especially in Wisconsin and Minnesota, for deposits of high-quality frac sand that the mining industry calls “Northern White” sand or “Ottawa” sand. Frac sand is a specialized type of sand that is added to fracking fluids that are injected into unconventional oil and gas wells during hydraulic fracturing (fracking or hydrofracking), a process that enhances petroleum extraction from tight (low permeability) reservoirs. Frac sand consists of natural sand grains with strict mineralogical and textural specifications that act as a proppant (keeping induced fractures open), extending the time of release and the flow rate of hydrocarbons from fractured rock surfaces in contact with the wellbore. The current sand mining surge has been driven by the boom in unconventional oil and gas production that has been largely spurred by advancements in technology promoting the expansion of hydraulic fracturing and horizontal drilling over the past decade. Because of its superior quality, the sand of the upper Midwest not only supports the majority of domestic oil and gas production, but it also supplies frac sand to some of Canada’s western shale basins. The principal sources of “Northern White” or “Ottawa” sand in the upper Midwest are the Middle and Upper Ordovician St. Peter Sandstone and the Lower Ordovician and Upper Cambrian Jordan Formation, with the Upper Cambrian Wonewoc and Mount Simon Formations gaining in importance. Additional frac sand sources to the south include the Upper Cambrian Hickory Sandstone Member of the Riley Formation in Texas, which is referred to informally as “Brown” or “Brady” sand, and the Middle Ordovician Oil Creek Formation in Oklahoma. More than 40 United States industry operators are involved in the mining, processing, transportation, and distribution of frac sand to a robust market that is fast-growing in the United States and throughout the world. In addition to the abrupt rise in frac sand mining and distribution, a new industry has emerged from the production of alternative proppants, such as coated sand and synthetic beads. Alternative proppants, developed through new technologies, are competing with supplies of natural frac sand. In the long term, the vitality of both industries will be tied to the future of hydraulic fracturing of tight oil and gas reservoirs, which will be driven by the anticipated increases in global energy consumption.

Open-File Report↗

USGS2004

Environmental behavior of two molybdenum porphyry systems

Our study focuses on the geology, hydrology, and geochemistry of a variety of molybdenum (Mo) porphyry systems. The systems are either high fluorine, granite, Climax-type, systems (e.g. Mount Emmons/ Redwell Mo deposit, Colorado and Questa Mo deposit, New Mexico) or low fluorine granodiorite systems (e.g. Buckingham Stockwork Mo deposit, Battle Mountain, Nevada and Cannivan Gulch Mo deposit, Montana). The water quality of streams, natural springs, mine discharge, and ground water from drill holes were assessed in the region of these deposits. The ultimate goal of our study is to understand the environmental behavior of these Mo porphyry systems in the context of geologic setting, hydrologic regime, and climate.

Conference Paper↗

USGS2006

Quantification of mass loading to Strawberry Creek near the Gilt Edge mine, Lawrence County, South Dakota, June 2003

Although remedial actions have taken place at the Gilt Edge mine in the Black Hills of South Dakota, questions remain about a possible hydrologic connection along shear zones between some of the pit lakes at the mine site and Strawberry Creek. Spatially detailed chemical sampling of stream and inflow sites occurred during low-flow conditions in June 2003 as part of a mass-loading study by the U.S. Geological Survey to investigate the possible connection of shear zones to the stream. Stream discharge was calculated by tracer dilution; discharge increased by 25.3 liters per second along the study reach, with 9.73 liters per second coming from three tributaries and the remaining increase coming from small springs and dispersed, subsurface inflow. Chemical differences among inflow samples were distinguished by cluster analysis and indicated that inflows ranged from those unaffected by interaction with mine wastes to those that could have been affected by drainage from pit lakes. Mass loading to the stream from several inflows resulted in distinct chemical changes in stream water along the study reach. Mass loading of the mine-related metals, including cadmium, copper, nickel, and zinc, principally occurred from the discharge from the Gilt Edge mine, and those metals were substantially attenuated downstream. Secondary loadings of metals occurred in the vicinity of the Oro Fino shaft and from two more inflows about 200 m downstream from there. These are both locations where shear zones intersect the stream and may indicate loading associatedwith these zones. Loading downstream from the Oro Fino shaft had a unique chemical character, high in base-metal concentrations, that could indicate an association with water in the pit lakes. The loading from these downstream sources, however, is small in comparison to that from the initial mine discharge and does not appear to have a substantial impact on Strawberry Creek.

South Dakota↗

USGS2019

Rare earth elements in coal and coal fly ash

The rare earth elements (REEs) are a group of 17 elements sharing similar chemical properties. They include yttrium (Y, atomic number 39), scandium (Sc, atomic number 21), and the 15 elements of the lanthanide series, atomic numbers 57 (lanthanum, La) to 71 (lutetium, Lu). Because promethium (Pm, atomic number 61) does not occur in the Earth’s crust and scandium typically has different geological occurrences from other REEs, they are not discussed further herein. REEs are, on average, more abundant than precious metals (for example, gold, silver, and platinum), but because of their unique geochemical properties, they do not commonly form economically viable ore deposits. Nevertheless, REEs are increasingly required for a range of modern applications in defense and renewable energy technologies and in commercial products, primarily as magnets, batteries, and catalysts. The United States currently (2018) produces REEs from a single mine in California, accounting for just 9 percent of global production, whereas 70 percent of global REE production comes from China. For these reasons, REEs are considered a critical resource, and the U.S. Geological Survey (USGS) has an interest in helping to identify new sources of REEs for domestic production. In 2017, coal use accounted for about 30 percent of the electric power generated in the United States. Fly ash, produced during the burning of coal, is a fine-grained solid derived from noncombustible constituents of coal, such as clay minerals and quartz. When coal is burned, REEs are retained and enriched in the fly ash and, as a result, fly ash has long been considered a potential resource for REEs. The United States has the world’s largest coal reserves and, even though gas-fired power generation has increased significantly in the last decade, the United States continues to produce vast quantities of fly ash, about half of which is beneficially reused, primarily in construction materials. The remainder is stored, mostly in landfills and impoundments. Thus, annual fly ash production, combined with fly ash already in storage, constitutes a large potential resource. Research into how to utilize coal and coal fly ash as sources of REEs is ongoing. Viable recovery of REEs from coal and coal ash requires identification of coals and ashes with the highest REE concentrations and development of workable methods for REE extraction and recovery. Understanding how REEs occur within fly ash, described in this fact sheet, is one of the keys to developing possible methods for their recovery.

Fact Sheet↗

USGS1998

Evidence for Proterozoic and late Cretaceous-early Tertiary ore-forming events in the Coeur d'Alene district, Idaho and Montana

New 40 Ar/ 39 Ar age spectra on sericite and lead isotope data on tetrahedrite, siderite, galena, bournonite, and stibnite, together with previously published isotopic, geochemical, and geologic studies provide evidence for two major vein-forming events in the Coeur d'Alene district and surrounding areas of the Belt basin. The data suggest that the zinc- and lead-rich veins (e.g., Bunker Hill and Star-Morning mines) formed in the Proterozoic (1.0 Ga), whereas the silver-rich veins (e.g., Silver belt mines), antimony veins (e.g., U.S. Antimony mine), and gold-bearing quartz veins (Murry subdistrict) formed in Late Cretaceous to early Tetitary time.

Economic Geology↗

USGS2019

Quantifying erosion rates by using terrestrial laser scanning at Malakoff Diggins State Historic Park, Nevada County, California, 2014–17

The abandoned hydraulic mine pit at Malakoff Diggins near Grass Valley, California, can produce large volumes of eroded sediment transportable by storm runoff. Sediment-laden water discharged from the pit is a major source of heavy metals to Humbug Creek and the South Yuba River. To develop a comprehensive sediment budget for the Malakoff Diggins mine pit and identify sources of sediment and metals within the pit that can become entrained as suspended sediment in runoff discharged from the pit, the U.S. Geological Survey, working in cooperation with the California Department of Water Resources, the California Department of Parks and Recreation, and the Nevada Irrigation District, used terrestrial laser scanning technology to quantify eroded volumes and erosion rates of sedimentary units exposed in the pit walls. The results for eroded volumes and rates reported here are part one of a three-part study. High-resolution terrestrial laser scanning surveys were repeated annually from 2014 through 2017, including before and after dry and wet winters, measuring centimeter-scale topographic changes to quantify the volume of sediment eroded from outcrops at Malakoff Diggins State Historic Park, located on the western slope of the northern Sierra Nevada about 17 kilometers northeast of Grass Valley, California. Terrestrial laser scanning enabled construction of three-dimensional maps of the complex outcrop surfaces, which could not be mapped non-destructively or in sufficient detail with traditional surveying techniques. Eroded volumes from discrete sedimentary units were calculated at four study sites (numbered 1, 2, 4, and 5) throughout the mine pit for the December 2014 to August 2017 period. Eroded volumes at the four study sites during the 32-month study ranged from 288 plus or minus (±) 13 cubic meters (m 3 ) of sediment at site 1 to 8,517±145 m 3 at site 4. Annual erosion rates at the four study sites ranged from 0.06±0.01 cubic meters per square meter per year (m 3 /m 2 /yr) at site 4 to 0.14±0.01 m 3 /m 2 /yr at site 2. The total eroded volume documented with terrestrial laser scanning at all four study sites from December 2014 to August 2017 was 12,934±334 m 3 of sediment, and the average annual erosion rate for the four study sites was 0.10±0.04 m 3 /m 2 /yr. Horizontal erosional-change maps indicate that a variety of erosional processes were responsible for the eroded sediment volume. These included areally broad and smaller-scale processes such as persistent dry ravel, periodic sheet wash, and frost heave and more localized and larger-scale processes such as coalescing fluvial incision, rotational landslides, and translational block-fall failures.

California↗

USGS2009

Geochemistry of surface water in alpine catchments in central Colorado, USA: Resolving host-rock effects at different spatial scales

The US Geological Survey is conducting a study of surface-water quality in the Rocky Mountains of central Colorado, an area of approximately 55,000 km 2 . Using new and existing geologic maps, the more than 200 rock formations represented in the area were arranged into 17 groups based on lithologic similarity. The dominant regional geologic feature affecting water quality in central Colorado is the Colorado mineral belt (CMB), a NE-trending zone hosting many polymetallic vein or replacement deposits, and porphyry Mo deposits, many of which have been mined historically. The influence of the CMB is seen in lower surface-water pH (<5), and higher concentrations of SO 4 2 - (>100 mg/L) and chalcophile metals such as Cu (>10 ??g/L), Zn (>100 ??g/L), and Cd (>1 ??g/L) relative to surface water outside the CMB. Not all streams within the CMB have been affected by mineralization, as there are numerous catchments within the CMB that have no mineralization or alteration exposed at the surface. At the regional-scale, and away from sites affected by mineralization, hydrothermal alteration, or mining, the effects of lithology on water quality can be distinguished using geochemical reaction modeling and principal components analysis. At local scales (100 s of km 2 ), effects of individual rock units on water chemistry are subtle but discernible, as shown by variations in concentrations of major lithophile elements or ratios between them. These results demonstrate the usefulness of regional geochemical sampling of surface waters and process-based interpretations incorporating geologic and geochemical understanding to establish geochemical baselines.

Applied Geochemistry↗

USGS2021

Groundwater/surface-water interactions in the Partridge River Basin and evaluation of hypothetical future mine pits, Minnesota

The Partridge River Basin (PRB) covers 156 square miles in northeastern Minnesota with headwaters in the Mesabi Iron Range. The basin is characterized by extensive wetlands, lakes, and streams in poorly drained and often thin glacial material overlying Proterozoic bedrock. To better understand the interaction between these extensive surface water features and the groundwater system, a three-dimensional, steady-state, groundwater-flow model of the PRB was developed by the U.S. Geological Survey in cooperation with the Great Lakes Indian Fish & Wildlife Commission using the finite-difference computer code MODFLOW-NWT. The model simulates steady-state base flow in streams and groundwater interactions using the streamflow routing (SFR2) package. Existing mining features including tailings basins, stockpiles, pumped mine pits, and flooded mine pits were simulated using either high hydraulic conductivity zones or the drain (DRN) package. The unsaturated zone flow (UZF) package was used to better represent the groundwater system in areas with a high water table and for wetlands often associated with such areas. UZF typically is used to represent unsaturated zone processes but also can simulate the rejection of recharge and groundwater discharge to the land surface when the water table is near land surface. The steady-state model used data from the 2011 to 2013 period when 2011 high-resolution land surface (light detecting and ranging [lidar]) data were available that reflected land-surface and water elevations from mining activity in the basin. The parameter-estimation software suite PEST_HP was used to obtain a best fit of the modeled to measured groundwater levels, streamflow, pit inflow rates, and mapped peat deposits. The PEST calibration used the target residuals from two models with the same model parameters and targets from two separate periods: (1) a 1995–2015 calibration model, which provided a larger number of calibration targets, and (2) a 2011–2013 mining conditions model, which included calibration targets that reflected conditions consistent with the modeled mine-workings topography. Calibration of the PRB model resulted in ranges of glacial horizontal hydraulic conductivity parameters that generally agreed with literature values and other models of the region. Horizontal hydraulic conductivity of the bedrock was higher in the upper bedrock layers where numerous and continuous fractures have been observed and lower in the deeper bedrock layers. Average basin-wide calibrated infiltration was 5.3 inches per year. An average of 4.6 inches per year of infiltration crosses the water table and becomes recharge and 0.7 inch per year is rejected by UZF due to saturated conditions at the land surface. Simulated groundwater runoff (the sum of rejected recharge and groundwater seepage to the land surface) can either be routed to streams or removed from the model as evapotranspiration. The calibrated model indicates relatively shallow groundwater-flow paths dominating and approximately 50 percent of the stream base flow coming from groundwater runoff. The 2011–2013 mining conditions model was then used to develop five model scenarios simulating the response of the groundwater and surface-water system to potential hydrologic stress. The purpose of these mine pit scenarios is to present a possible workflow to quantify a model’s uncertainty for a given model forecast and serve as a possible guide for initial data collection that may improve a future model’s ability to make such a forecast. The scenarios included one scenario with the currently existing Peter Mitchell pit at final buildout and flooded to an elevation of 1,500 feet, and four scenarios with a hypothetical, new mine pit plus the flooded Peter Mitchell at final buildout. The five model scenarios were used to forecast streamflow at six locations in the PRB, pit inflow rates for the new mine pits and the flooded Peter Mitchell pit, and the average depth to water in 12 wetlands. A linear uncertainty analysis was performed using information from the PEST calibration and tools in the PyEMU python package to assess model uncertainty propagation to the model forecasts. Streamflows generally were reduced with future mining and the greatest streamflow reductions occurred from the flooded Peter Mitchell Pit, probably due to its large size. Average depth to groundwater in wetlands was most affected the closer the wetland was to a new mine pit. Linear uncertainty methods were also used to evaluate data worth, which is the ability for potential new groundwater elevation observations to reduce the uncertainty in scenario forecasts. Data worth was performed for a grid of new hydraulic head observations. Overall, areas with nonnegligible data worth generally corresponded to wetland areas with no groundwater seepage to land surface from UZF. These model behaviors indicated that the land-surface boundary condition simulated by the UZF package was pinning the groundwater elevations to the land surface in areas with groundwater seepage (33 percent of the 2011–2013 base conditions model) such that the sensitivity to new observations in these areas was minimal. Therefore, representing wetlands as boundary conditions minimized the usefulness of data worth calculations because wetland areas were present over a large part of the model domain. Probabilistic capture zones were estimated for each of the mines in the model scenarios. A capture zone represents the area contributing recharge to a model feature, like a well or a mine pit, and can be calculated by forward tracking particles from the water table. By using Monte Carlo techniques, it is possible to generate estimated capture zones that include the probability of recharge capture given the uncertainty present in the model. Monte Carlo techniques use randomly generated model parameter sets sampled from a plausible parameter range to create many possible realizations. The resulting capture zone arrays were calculated by tallying the total number of realizations in which a particle from a model cell was captured by the feature. Probabilities from the Monte Carlo runs ranged from 1 (captured in 100 percent of the runs) near the pits to 0 (captured in 0 percent of the runs) at the edges of the capture zone. Capture zones were not always spatially continuous; for example, the capture zone for the proposed mine pits south of the flooded Peter Mitchell pit was discontinuous with capture surrounding the proposed mine pit and north of the flooded Peter Mitchell pit. This northern section represents deeper groundwater flow paths that originate in the topographic high, move under the flooded pit, and discharge into the proposed pit. This pattern of capture indicates the possibility of some deeper flow through the upper fractured bedrock when the shallow groundwater flow system is modified. These results underscore that future site-specific applications of the base condition model require the input of site-specific data and recalibration to focus on the site of interest.

Minnesota↗

USGS1944

Graphite deposits on the north side of the Kigluaik Mountains, Seward Peninsula, Alaska

The graphite deposits on the north side of the Kigluaik Mountains have been known for many years, and have yielded a small quantity of flake graphite, but they have been only slightly developed. The author spent 4 days of June 1943 in company with Mr. H. E. Heide, mining engineer of the Bureau of Mines, and Mr. Norman Tweet, part owner of one of the properties. Acknowledgment is due Mr. John Read and the Lomen Commercial Company for many favors rendered in connection with the investigation. The chemical analyses in this report were made by F. S. Grimaldi, of the Geological Survey. The deposits were examined many years ago by Harrington 1/ who discussed the general geology and described the developments up to the date of'his examination. Much of the history of the district given below is taken from his report. According to Harrington, the first claims were staked in 1900. Two principal groups of claims were worked, those of the Uncle Sam Alaska Mining Syndicate and those of the Alaska Graphite Mining Company. Harrington records that the claims of the Alaska Graphite Mining Company were staked in part in 1905 and in part in 1915 or 1916. A production of 35 tons picked from talus was reported for 1907. According to Mertie, 2/ the production in 1916 was about 100 tons, which according to Harrington, was shipped in 1917, together with several tons mined from an open cut in that year. In 1912, according to Mertie, shipments totalling 130 tons of graphite were made by the Uncle Sam. Alaska Mining Syndicate, and 300 tons were ready for shipment in 1916. Harrington, who visited the area in 1917, reported that no shipments were made in that year by that company. No records of subsequent production have been found. The properties apparently lay dormant until the summer of 1943, when renewed interest was expressed in the restaking of claims. Graphite deposits are widespread in the Kigluaik Mountains. 3/ The deposits described in the report have received the most attention because of their relative accessibility. These deposits are about 36 miles northwest of Nome and about 26 miles east of Teller (see fig. 1). The principal deposits are 2 to 3 miles from an arm of the Imuruk Basin, and about 27 miles by salt water from Teller. Most of the Imuruk Basin is shallow and does not exceed a fathom in depth at distances as much as a mile from shore. Arrangements may be made at Teller to charter small boats for the trip to the graphite-bearing area. The portion of the area between the Kigluaik Mountains and the Imuruk Basin (see fig. 2) is chiefly a gently-sloping alluvial fan, in which the larger creeks are intrenched from 10 to 30 feet near the mountain front. The creek herein called Graphite Creek, the northeasternmost creek shown on figure 2, is about 2 miles southwest of the Cobblestone River. Ruby, Ptarmigan and Trail Creeks transect the mountain front in the order named, proceeding southwestward from Glacier Creep. Farther to the southwest, some of the smaller creeks are unnamed. The creek about 1.4 miles southwest of Trail Creek is herein called Christophosen Creek in order to have a convenient means of reference.

Alaska↗

USGS1987

Geology of the Holocene surficial uranium deposit of the north fork of Flodelle Creek, northeastern Washington (USA)

The north fork of Flodelle Creek drainage basin in northeastern Washington contains the first surficial uranium deposit to be mined in the United States. The uranium was leached from granitic bedrock and fixed in organic-rich pond sediments. The distribution of these pond sediments and, therefore, the uranium has been strongly influenced by relict glacial topography, slope processes, and beaver activity. The north fork of Flodelle Creek drainage basin was covered by the Cordilleran ice sheet during the Fraser (late Wisconsin) glaciation. Till and outwash were deposited on the valley slopes and valley floor as ice receded. Outwash incision and melting of stagnant ice led to formation of a terrace and kames. Shortly after deglaciation, a small pond formed in the upper part of the valley when unconsolidated glacial sediment slumped off the valley slopes and restricted drainage. Fluvial processes dominated in the central and downstream parts of the valley for several thousand years after deglaciation, although drainage was partly restricted by kames. Beavers began to occupy and build dams on the wide outwash plains in the valley floor ∼5000 yr B.P. Beaver ponds in the central part of the basin subsequently filled with sediment and were abandoned, whereas downstream ponds remained relatively free of clastic input and are presently occupied by beavers. Ponds in the drainage basin have been sinks for fine-grained, organic-rich sediments. These organic-rich sediments provide a suitable geochemical environment for precipitation and adsorption of uranium leached from granitic bedrock into ground, spring, and surface waters. Processes of pond formation have thus been important in the development of surficial uranium deposits in the north fork of Flodelle Creek drainage basin and may have similar significance in other areas.

Washington↗

USGS1888

Geology of the quicksilver deposits of the Pacific slope, with an atlas

The field work of the investigations recorded in this volume occupied nearly the whole of three seasons, beginning in 1883. All the mines might have been examined and the maps colored in a much shorter time, but it was found soon after the examinations were begun that they could not be completed satisfactorily without also solving some important general problems affecting the whole region, and much of the time spent was devoted to these questions.

California↗

USGS2017

Manganese

Manganese is an essential element for modern industrial societies. Its principal use is in steelmaking, where it serves as a purifying agent in iron-ore refining and as an alloy that converts iron into steel. Although the amount of manganese consumed to make a ton of steel is small, ranging from 6 to 9 kilograms, it is an irreplaceable component in the production of this fundamental material. The United States has been totally reliant on imports of manganese for many decades and will continue to be so for at least the near future. There are no domestic reserves, and although some large low-grade resources are known, they are far inferior to manganese ores readily available on the international market. World reserves of manganese are about 630 million metric tons, and annual global consumption is about 16 million metric tons. Current reserves are adequate to meet global demand for several decades. Global resources in traditional land-based deposits, including both reserves and rocks sufficiently enriched in manganese to be ores in the future, are much larger, at about 17 billion metric tons. Manganese resources in seabed deposits of ferromanganese nodules and crusts are larger than those on land and have not been fully quantified. No production from seabed deposits has yet been done, but current research and development activities are substantial and may bring parts of these seabed resources into production in the future. The advent of economically successful seabed mining could substantially alter the current scenario of manganese supply by providing a large new source of manganese in addition to traditional land-based deposits. From a purely geologic perspective, there is no global shortage of proven ores and potential new ores that could be developed from the vast tonnage of identified resources. Reserves and resources are very unevenly distributed, however. The Kalahari manganese district in South Africa contains 70 percent of the world’s identified resources and about 25 percent of its reserves. South Africa, Brazil, and Ukraine together accounted for nearly 65 percent of reserves in 2013. The combination of total import reliance for manganese, the mineral commodity’s essential uses in our industrialized society, and the potential for supply disruptions because of the limited sources of the ore makes manganese among the most critical minerals for the United States. Manganese is the 12th most abundant element in Earth’s crust. Its concentration varies among common types of rocks, mostly in the range of from 0.1 to 0.2 percent. The highest quality manganese ores contain from 40 to 45 percent manganese. The formation of these ores requires specialized geologic conditions that concentrate manganese at several hundred times its average crustal abundance. The dominant processes in forming the world’s principal deposits take place in the oceans. As a result, most important manganese deposits occur in ancient marine sedimentary rocks that are now exposed on continents as a result of subsequent tectonic uplift and erosion. In many cases, other processes have further enriched these manganiferous sedimentary rocks to form some of today’s highest grade ores. Modern seabed resources of ferromanganese nodules cover vast areas of the present ocean floor and are still forming by complex interactions of marine microorganisms, manganese dissolved in seawater, and chemical processes on the seabed. Manganese is ubiquitous in soil, water, and air. It occurs most often in solid form but can become soluble under acidic conditions. Manganese mining, like any activity that disturbs large areas of Earth’s surface, has the potential to produce increases in manganese concentrations that could be harmful to humans or the environment if not properly controlled. Although manganese is an essential nutrient for humans and most other organisms, overexposure can lead to neurotoxicity in humans. Workers at manganese mining and processing facilities have the greatest potential to inhale manganese-rich dust. Without proper protective equipment, these workers may develop a permanent neurological disorder known as manganism. Each manganese mine is unique and presents its own suite of potential hazards and preventative measures. Likewise, various nations have their own sets of standards to ensure safe mining, isolation of mine waste, treatment of mine waters, and mine closure and restoration. Interest in mining trace metals contained in ferromanganese nodules and crusts on the seabed has increased rapidly in the past decade. Prime areas for future research include overcoming the technological challenges presented by mining as deep as 6,500 meters below sea level and understanding and mitigating the potential impacts of seabed mining on marine ecosystems.

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