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Digital data and geologic map of the Powder Mill Ferry Quadrangle, Shannon and Reynolds counties, Missouri

The geology of the Powder Mill Ferry 7 1/2-minute quadrangle , Shannon and Reynolds Counties, Missouri was mapped from 1997 through 1998 as part of the Midcontinent Karst Systems and Geologic Mapping Project, Eastern Earth Surface Processes Team. The map supports the production of a geologic framework that will be used in hydrogeologic investigations related to potential lead and zinc mining in the Mark Twain National Forest adjacent to the Ozark National Scenic Riverways (National Park Service). Digital geologic coverages will be used by other federal and state agencies in hydrogeologic analyses of the Ozark karst system and in ecological models.

IMAP↗

Applications of imaging spectroscopy data: A case study at Summitville, Colorado

From 1985 through 1992, the Summitville open-pit mine produced gold from lowgrade ore using cyanide heap-leach techniques, a method to extract gold whereby the ore pile is sprayed with water containing cyanide, which dissolves the minute gold grains. Environmental problems due to mining activity at Summitville include significant increases in acidic and metal-rich drainage from the site, leakage of cyanide-bearing solutions from the heap-leach pad into an underdrain system, and several surface leaks of cyanide-bearing solutions into the Wightman Fork of the Alamosa River. In general, drainage from the Summitville mine moves downslope into the Wightman Fork, a small tributary of the Alamosa River, which in turn flows east into the Terrace Reservoir before entering the agricultural lands of the San Luis Valley. The increase in the trace-metal burden of the Alamosa River watershed due to the mining activities at Summitville is of concern to farmers and fisherman, as well as Federal and State of Colorado agencies having responsibility for land stewardship. The environment of the Summitville area is a result of 1) its geologic evolution, that culminated in the formation of precious-metal mineral deposits; and 2) previous metal mining activity. Mining accentuates, accelerates, and pertubates natural geochemical processes. The development of underground workings, open pits, mill tailings, and spoil heaps and the extractive processing of ore enhances the likelihood of releasing chemicals and elements to the surrounding areas and at increased rates relative to unmined areas. Both mined and unmined mineralized areas can produce acid drainage from the formation and movement of highly acidic water rich in heavy metals. This acidic water forms principally through the chemical reaction of oxygenated surface water and shallow subsurface water with rocks that contain sulfide minerals, producing sulphuric acid. Heavy metals can be leached by the acid solution that comes in contact with mineralized rocks, a process that may be enhanced by bacterial action. The resulting fluids may be highly toxic and, when mixed with groundwater, surface water, and soil, may have harmful effects on humans, animals, and plants. Thus, understanding the geologic and hydrologic history of this area is a critical piece of the environmental puzzle in the Summitville area. The Summitville mine operators had ceased active mining and begun environmental remediation, including treatment of the heap-leach pile and installation of a water-treatment facility, when it declared bankruptcy in December 1992 and abandoned the mine site. The U.S. Environmental Protection Agency (EPA) immediately took over the Summitville site under EPA Superfund Emergency Response authority. Summitville has focused public attention on the environmental effects of modern mineral-resource development. Soon after the mine was abandoned, Federal, State, and local agencies, along with Alamosa River water users and private companies, began extensive studies at the mine site and surrounding areas. These studies included analysis of water, soil, livestock and vegetation. The role of the U.S. Geological Survey (USGS) was to provide geologic, hydrologic and agricultural information about the mine and surrounding area and to describe and evaluate the environmental condition of the Summitville mine and the downstream effects of the mine on the San Luis Valley (King 1995).

Colorado↗

Mineral resource assessment of rare-earth elements, thorium, titanium, and uranium in the Greenville 1° x 2° quadrangle, South Carolina, Georgia, and North Carolina

Mineral resources of the Greenville 1° x 2° quadrangle, South Carolina, Georgia, and North Carolina, were assessed between 1984 and 1990 under the Conterminuous United States Mineral Assessment Program (CUSMAP) of the U.S. Geological Survey (USGS). The mineral resource assessments were made on the basis of geologic, geochemical, and geophysical investigations and the presence of mines, prospects, and mineral occurrences from the literature. This report is an assessment of the rare-earth elements (REE), thorium, titanium, and uranium resources in the Greenville quadrangle and is based on heavy mineral concentrates collected in 1951-54 by the USGS (Overstreet and others, 1968; Caldwell and White, 1973; Cuppels and White, 1973); on the results of the U.S. Department of Energy, National Uranium Resource Evaluation (NURE) sampling program (Ferguson, 1978, 1979); on analyses of stream-sediment and heavy-mineral-concentrate samples (Jackson and Moore, 1992, G.C Cullin, USGS, unpub. data, 1992) on maps showing aerial gamma radiation in the Greenville quadrangle (D.L. Daniels, USGS, unpub. data, 1992); and on the geology as mapped by Nelson and others (1987, 1989).

Georgia, North Carolina, South Carolina↗

Analyses of rock and stream-sediment samples from the Sumdum C-4 Quadrangle, Alaska

Analytical data for 31 rock and 33 stream-sediment samples from the Sumdum C-4 , 1:63,360 scale quadrangle are presented in this report, together with a statistical treatment of the data. The samples were collected in 1969 as part of the Heavy Metals Program of the U.S. Geological Survey. The most comprehensive discussion of the geology of the study area is a report by A. F. Buddington and Theodore Chapin (1929). Known metalliferous lodes of the area are described and additional references to specific areas are given by Berg and Cobb (1967). Additional data is given in reports by Herbert and Race (1964) and Alaska Department of Mines (1950). Supplemental publications are being prepared on the general geology and mineral occurrences of the study area.

Alaska↗

Remote-sensing methods for monitoring surface coal mining in the northern Great Plains

Recent studies at a large surface coal mine in southern Montana confirm that remote sensing is both feasible and effective for gathering land-use and environmental data (spatial, dynamic, and seasonal) for large-scale surface mines in the northern Great Plains. The Western Energy Co.'s Rosebud mine near Colstrip, Mont., was selected as a test site because it typifies surface operations in the Powder River Basin of Montana and Wyoming and elsewhere in the northern Great Plains. Several basic interpretive and analytical remote-sensing techniques were used to identify and delineate various categories of surface-mining operations and concurrent stages of reclamation that characterize most, if not all, such mining operations. Color infrared and black-and-white aerial photographs and a black-and-white band 5 Landsat image were used to identify (1) high wall and bench areas, (2) ungraded spoils, (3) graded and recontoured areas, (4) revegetated recontoured areas, (5) natural and impounded surface water, and (6) miscellaneous areas. Over the lifespan of an extensive surface mine, cultural and natural processes and cumulative environmental effects can be monitored by capitalizing on the close correlation between enhanced satellite imagery, infrared and (or) black-and-white aerial photography, standard large-scale topographic maps (such as U.S. Geological Survey 7½-minute quadrangle maps), and results of onsite inspection of mining and reclamation by Federal or State agencies.

Montana↗

Questa baseline and pre-mining ground-water quality investigation. 25. Summary of results and baseline and pre-mining ground-water geochemistry, Red River Valley, Taos County, New Mexico, 2001-2005

Active and inactive mine sites are challenging to remediate because of their complexity and scale. Regulations meant to achieve environmental restoration at mine sites are equally challenging to apply for the same reasons. The goal of environmental restoration should be to restore contaminated mine sites, as closely as possible, to pre-mining conditions. Metalliferous mine sites in the Western United States are commonly located in hydrothermally altered and mineralized terrain in which pre-mining concentrations of metals were already anomalously high. Typically, those pre-mining concentrations were not measured, but sometimes they can be reconstructed using scientific inference. Molycorp?s Questa molybdenum mine in the Red River Valley, northern New Mexico, is located near the margin of the Questa caldera in a highly mineralized region. The State of New Mexico requires that ground-water quality standards be met on closure unless it can be shown that potential contaminant concentrations were higher than the standards before mining. No ground water at the mine site had been chemically analyzed before mining. The aim of this investigation, in cooperation with the New Mexico Environment Department (NMED), is to infer the pre-mining ground-water quality by an examination of the geologic, hydrologic, and geochemical controls on ground-water quality in a nearby, or proximal, analog site in the Straight Creek drainage basin. Twenty-seven reports contain details of investigations on the geological, hydrological, and geochemical characteristics of the Red River Valley that are summarized in this report. These studies include mapping of surface mineralogy by Airborne Visible-Infrared Imaging Spectrometry (AVIRIS); compilations of historical surface- and ground- water quality data; synoptic/tracer studies with mass loading and temporal water-quality trends of the Red River; reaction-transport modeling of the Red River; environmental geology of the Red River Valley; lake-sediment chemistry; geomorphology and its effect on ground-water flow; geophysical studies on depth to ground-water table and depth to bedrock; bedrock fractures and their potential influence on ground-water flow; leaching studies of scars and waste-rock piles; mineralogy and mineral chemistry and their effect on ground-water quality; debris-flow hazards; hydrology and water balance for the Red River Valley; ground-water geochemistry of selected wells undisturbed by mining in the Red River Valley; and quality assurance and quality control of water analyses. Studies aimed specifically at the Straight Creek natural-analog site include electrical surveys; high-resolution seismic survey; age-dating with tritium/helium; water budget; ground-water hydrology and geochemistry; and comparison of mineralogy and lithology to that of the mine site. The highly mineralized and hydrothermally altered volcanic rocks of the Red River Valley contain several percent pyrite in the quartz-sericite-pyrite (QSP) alteration zone, which weather naturally to acid-sulfate surface and ground waters that discharge to the Red River. Weathering of waste-rock piles containing pyrite also contributes acid water that eventually discharges into the Red River. These acid discharges are neutralized by circumneutral-pH, carbonate-buffered surface and ground waters of the Red River. The buffering capacity of the Red River, however, decreases from the town of Red River to the U.S. Geological Survey (USGS) gaging station near Questa. During short, but intense, storm events, the buffering capacity is exceeded and the river becomes acid from the rapid flushing of acidic materials from natural scar areas. The lithology, mineralogy, elevation, and hydrology of the Straight Creek proximal analog site were found to closely approximate those of the mine site with the exception of the mine site?s Sulphur Gulch catchment. Sulphur Gulch contains three subcatchments?upper Sulphur Gulch, Blind Gulch, and Spring Gulc

New Mexico↗

Regional geochemical maps of the Tonopah 1 degree by 2 degrees Quadrangle, Nevada, based on samples of stream sediment and nonmagnetic heavy-mineral concentrate

This report is part of a series of geologic, geochemical, and geophysical maps of the Tonopah 1° x 2° quadrangle, Nevada, prepared during studies of the area for the Conterminous United States Mineral Assessment Program (CUSMAP). Included here are 21 maps showing the distributions of selected elements or combinations of elements. These regional geochemical maps are based on chemical analyses of the minus-60 mesh (0.25 mm) fraction of stream-sediment samples and the nonmagnetic heavy-mineral concentrate derived from stream sediment. Stream sediments were collected at 1,217 sites. Our geochemical studies of mineralized rock samples provide a framework for evaluating the results from stream sediments. The Tonopah 1° x 2° quadrangle comprises about 19,100 km 2 (7,450 mi 2 ) in west-central Nevada (fig. 1). Topography is typical of the Basin and Range province, consisting of angular mountain ranges separated by broad valleys that comprise about half the area. Topographic relief is generally about 1,000 m but in some places is more than 1,500 m. Most of the ranges have well-developed drainages in steep-walled canyons occupied by intermittent streams. The climate is semi-arid to arid. Pinon pine and juniper grow in most places at elevations above 2,100 m, and sagebrush is abundant at lower elevations. Major access is provided by U.S. Routes 6 and 95, and there are numerous county maintained gravel roads and unmaintained jeep trails. Bedrock geology of the Tonopah quadrangle is a complex mosaic of late Precambrian to Tertiary rocks juxtaposed by numerous thrust and high-angle faults. Useful geologic summaries can be found in reports by Ross (1961), Albers and Stewart (1972), Stewart and Carlson (1978), and Kleinhampl and Ziony (1985). Mineral prospects and mines occur in igneous, metamorphic, and sedimentary rocks of all ages, and mines are particularly abundant in the central and western parts of the quadrangle. The complex geology produces clasts of mixed lithology in alluvium in all drainage basins sampled in this study, and the numerous mines and prospects probably contaminate many drainages. The geochemical maps in this report are based on analytical results reported by Fairfield and others (1985), Hill and others (1986), and Siems and others (1986). These reports also describe the sample preparation and analytical methods and provide information on the location of the sample sites.

Nevada↗

Graphite

Graphite is a form of pure carbon that normally occurs as black crystal flakes and masses. It has important properties, such as chemical inertness, thermal stability, high electrical conductivity, and lubricity (slipperiness) that make it suitable for many industrial applications, including electronics, lubricants, metallurgy, and steelmaking. For some of these uses, no suitable substitutes are available. Steelmaking and refractory applications in metallurgy use the largest amount of produced graphite; however, emerging technology uses in large-scale fuel cell, battery, and lightweight high-strength composite applications could substantially increase world demand for graphite. Graphite ores are classified as “amorphous” (microcrystalline), and “crystalline” (“flake” or “lump or chip”) based on the ore’s crystallinity, grain-size, and morphology. All graphite deposits mined today formed from metamorphism of carbonaceous sedimentary rocks, and the ore type is determined by the geologic setting. Thermally metamorphosed coal is the usual source of amorphous graphite. Disseminated crystalline flake graphite is mined from carbonaceous metamorphic rocks, and lump or chip graphite is mined from veins in high-grade metamorphic regions. Because graphite is chemically inert and nontoxic, the main environmental concerns associated with graphite mining are inhalation of fine-grained dusts, including silicate and sulfide mineral particles, and hydrocarbon vapors produced during the mining and processing of ore. Synthetic graphite is manufactured from hydrocarbon sources using high-temperature heat treatment, and it is more expensive to produce than natural graphite. Production of natural graphite is dominated by China, India, and Brazil, which export graphite worldwide. China provides approximately 67 percent of worldwide output of natural graphite, and, as the dominant exporter, has the ability to set world prices. China has significant graphite reserves, and China’s graphite production is expected to increase, although rising labor costs and some mine production problems are developing. China is expected to continue to be the dominant exporter for the near future. Mexico and Canada export graphite mainly to the United States, which has not had domestic production of natural graphite since the 1950s. Most graphite deposits in the United States are too small, low-grade, or remote to be of commercial value in the near future, and the likelihood of discovering larger, higher-grade, or favorably located domestic deposits is unlikely. The United States is a major producer of synthetic graphite.

Professional Paper↗

Arsenic and mercury contamination related to historical goldmining in the Sierra Nevada, California

Arsenic (As) is a naturally occurring constituent in low-sulphide gold-quartz vein deposits, the dominant deposit type for lode mines in the Sierra Nevada Foothills (SNFH) gold (Au) province of California. Concentrations of naturally occurring mercury (Hg) in the SNFH Au province are low, but extensive use and loss of elemental Hg during amalgamation processing of ore from lode and placer Au deposits led to widespread contamination of Hg in the Sierra Nevada foothills and downstream areas, such as the Sacramento–San Joaquin Delta and San Francisco Bay. This review paper provides an overview of As and Hg contamination related to historical Au mining in the Sierra Nevada of California. It summarizes the geology, mineralogy, and geochemistry of the Au deposits, and provides information on specific areas where detailed studies have been done in association with past, ongoing, and planned remediation activities related to the environmental As and Hg contamination. Arsenic is a naturally occurring constituent in low-sulphide Au-quartz vein deposits, the dominant deposit type for lode mines in the Sierra Nevada Foothills (SNFH) Au province ( Ashley 2002 ). Because of elevated concentrations of As in accessory iron-sulphide minerals including arsenopyrite (FeAsS) and arsenian pyrite (Fe(S,As) 2 ), As is commonly a contaminant of concern in lode Au mine waste, including waste rock and mill tailings. The principal pathways of human As exposure from mine waste include ingestion of soil or drinking water, and inhalation of dust in contaminated areas ( Mitchell 2014 ). Concentrations of naturally occurring Hg in the SNFH Au province are low, but extensive use and loss of elemental Hg during amalgamation processing of ore from lode and placer Au deposits ( Churchill 2000 ) led to widespread contamination of Hg in the Sierra Nevada foothills and downstream areas, such as the Sacramento–San Joaquin Delta and San Francisco Bay ( Alpers et al. 2005 a ). Conversion of Hg to monomethylmercury (MeHg) by sulphate-reducing and iron-reducing microbes facilitates its bioaccumulation ( Wiener et al. 2003 ). The human Hg exposure pathway of main concern is ingestion of MeHg from sport (non-commercial) fish, especially higher trophic levels such as bass species ( Davis et al. 2008 ). Wildlife exposure to MeHg is also a concern because of chronic and reproductive effects, for example in fish-eating and invertebrate-foraging birds (e.g. Wiener et al. 2003 ; Eagles-Smith et al. 2009 ; Ackerman et al. 2016 ).

California↗

Preliminary report on diamond-drill exploration on Outlaw Mesa, Mesa County, Colorado

Outlaw Mesa is northeast of the Dolores River, about 10 miles southeast of Gateway, Mesa County, Colo. It is an oval-shaped area of about 17 square miles lying mostly within T. 50 N., R. 17 W«, and T. 50 No, R. 18 W., New Mexico principal meridian. The area is accessible by three unimproved roads from Colorado Highway 141. The altitude of the mesa ranges from about 5,500 feet to over 7,000 feet. Total production from Outlaw Mesa from 1914 to 1949 was about 4,000 tons of carnotite ore, having an estimated grade of about 0.50 percent U30Q and 2.5 percent V 2 O 5 . The production from 1949 to October 1951 was about 18,000 tons, having an estimated grade of about 0.35 percent U 3 O 8 and 1.6 percent V 2 O 5 . About 80 percent of the production from 1949 to October 1951 was from deposits discovered by U. S. Geological Survey diamond-drilling in public land, now leased to the Climax Uranium Co. A more complete history of mining and production OE Outlaw Mesa has been given in earlier reports. The results of Geological Survey exploration on Outlaw Mesa are summarized in this preliminary report. A final and more comprehensive report will be transmitted later. No additional drilling is planned.

Colorado↗

Climate change lessons from a warm world

In the early 1970’s to early 1980’s Soviet climatologists were making comparisons to past intervals of warmth in the geologic record and suggesting that these intervals could be possible analogs for 21st century “greenhouse” conditions. Some saw regional warming as a benefit to the Soviet Union and made comments along the lines of “Set fire to the coal mines!” These sentiments were alarming to some, and the United States Geological Survey (USGS) leadership thought they could provide a more quantitative analysis of the data the Soviets were using for the most recent of these warm intervals, the Early Pliocene.

Transactions of the Leicester Literary & Philosoph↗

Aeromagnetic maps of the Mazatzal Wilderness and contiguous roadless areas, Gila, Maricopa, and Yavapai counties, Arizona

The Mazatzal Wilderness and contiguous roadless areas are located in Tonto and Coconino National Forests, west and southwest of Payson, and are almost exactly in the geographic center of Arizona. This is a region of relatively small mining districts and few mines, but occurrences of many different metals are widespread. The Mazatzal Mountains constitute the dominant physiographic feature of the wilderness. The eastern slopes of these mountains rise steeply from about 3,500 ft in altitude along the valley of Rye Creek east of the range, to 7,903 ft at Mazatzal Peak. To the west, the range slopes steeply from the crest then more gently along the lower flanks to the Werde River, one of the main drainage channels of Arizona. In the northern part of the wilderness, the East Werde River, a tributary of the Verde, occupies a deep canyon that separates the Mazatzal Mountains from mesas to the north. The lowest parts of the wilderness have altitudes of about 2,200 ft and are located near Bartlett Reservoir in the southwestern part of the area studied. Two aeromagnetic surveys were flown and interpreted to aid in the delineation of subsurface lithology and structure: one survey was flown at a low level (1,000 ft above ground) and the other at a high level (9,000 ft above sea level). In addition, the results of a small-scale electromagnetic (EM) survey are briefly discussed; the surface EM survey took place in an area of copper concentrations and past exploration activity to look for evidence of massive sulfide mineralization. Studies of the geology, geochemistry (Marsh and others, 1983a, b, Erickson, 1984), mines and prospects (Ellis, 1982), and mineral resource potential (Wrucke and others, 1983) of the Mazatzal Wilderness and contiguous roadless areas have been published elsewhere.

Arizona↗

Geologic map of the Granite 7.5' quadrangle, Lake and Chaffee Counties, Colorado

The geologic map of the Granite 7.5' quadrangle, Lake and Chaffee Counties, Colorado, portrays the geology in the upper Arkansas valley and along the lower flanks of the Sawatch Range and Mosquito Range near the town of Granite. The oldest rocks, exposed in the southern and eastern parts of the quadrangle, include gneiss and plutonic rocks of Paleoproterozoic age. These rocks are intruded by younger plutonic rocks of Mesoproterozoic age. Felsic hypabyssal dikes, plugs, and plutons, ranging in age from Late Cretaceous or Paleocene to late Oligocene, locally intruded Proterozoic rocks. A small andesite lava flow of upper Oligocene age overlies Paleoproterozoic rock, just south of the Twin Lakes Reservoir. Gravelly fluvial and fan deposits of the Miocene and lower Pliocene(?) Dry Union Formation are preserved in the post-30 Ma upper Arkansas valley graben, a northern extension of the Rio Grande rift. Mostly north-northwest-trending faults displace deposits of the Dry Union Formation and older rock units. Light detection and ranging (lidar) imagery suggests that two short faults, near the Arkansas River, may displace surficial deposits as young as middle Pleistocene. Surficial deposits of middle Pleistocene to Holocene age are widespread in the Granite quadrangle, particularly in the major valleys and on slopes underlain by the Dry Union Formation. The main deposits are glacial outwash and post-glacial alluvium; mass-movement deposits transported by creep, debris flow, landsliding, and rockfall; till deposited during the Pinedale, Bull Lake, and pre-Bull Lake glaciations; rock-glacier deposits; and placer-tailings deposits formed by hydraulic mining and other mining methods used to concentrate native gold. Hydrologic and geologic processes locally affect use of the land and locally may be of concern regarding the stability of buildings and infrastructure, chiefly in low-lying areas along and near stream channels and locally in areas of moderate to steep slopes. Low-lying areas along major and minor streams are subject to periodic stream flooding. Mass-movement deposits and deposits of the Dry Union Formation that underlie moderate to steep slopes are locally subject to creep, debris-flow deposition, and landsliding. Proterozoic rocks that underlie steep slopes are locally subject to rockfall. Sand and gravel resources for construction and other uses in and near the Granite quadrangle are present in outwash-terrace deposits of middle and late Pleistocene age along the Arkansas River and along tributary streams in glaciated valleys.

Colorado↗

Hydrologic data from wells at or in the vicinity of the San Juan coal mine, San Juan County, New Mexico

In 2010, in cooperation with the Mining and Minerals Division (MMD) of the State of New Mexico Energy, Minerals and Natural Resources Department, the U.S. Geological Survey (USGS) initiated a 4-year assessment of hydrologic conditions at the San Juan coal mine (SJCM), located about 14 miles west-northwest of the city of Farmington, San Juan County, New Mexico. The mine produces coal for power generation at the adjacent San Juan Generating Station (SJGS) and stores coal-combustion byproducts from the SJGS in mined-out surface-mining pits. The purpose of the hydrologic assessment is to identify groundwater flow paths away from SJCM coal-combustion-byproduct storage sites that might allow metals that may be leached from coal-combustion byproducts to eventually reach wells or streams after regional dewatering ceases and groundwater recovers to predevelopment levels. The hydrologic assessment, undertaken between 2010 and 2013, included compilation of existing data. The purpose of this report is to present data that were acquired and compiled by the USGS for the SJCM hydrologic assessment.

New Mexico↗

Ground geophysical study of the Buckeye mine tailings, Boulder watershed, Montana

The Buckeye mine site is located in the Boulder River watershed along Basin Creek, in northern Jefferson County, Montana. This project is part of the Boulder River watershed Abandoned Mine Lands Initiative, and is a collaborative effort between the U.S. Geological Survey and Bureau of Land Management in the U.S. Department of the Interior, and the U.S. Forest Service in the U.S. Department of Agriculture. The site includes a large flotation milltailing deposit, which extends to the stream and meadows below the mine. These tailings contain elevated levels of metals, such as silver, cadmium, copper, lead, and zinc. Metal-rich fluvial tailings containing these metals, are possible sources of ground and surface water contamination. Geophysical methods were used to characterize the sediments at the Buckeye mine site. Ground geophysical surveys, including electromagnetics, DC resistivity, and total field magnetic methods, were used to delineate anomalies that probably correlate with subsurface metal contamination. Subsurface conductivity was mapped using EM-31 and EM-34 terrain conductivity measuring systems. The conductivity maps represent variation of concentration of dissolved solids in the subsurface from a few meters, to an approximate depth of 30 meters. Conductive sulfides several centimeters thick were encountered in a shallow trench, dug in an area of very high conductivity, at a depth of approximately 1 to1.5 meters. Laboratory measurements of samples of the sulfide layers show the conductivity is on the order of 1000 millisiemens. DC resistivity soundings were used to quantify subsurface conductivity variations and to estimate the depth to bedrock. Total field magnetic measurements were used to identify magnetic metals in the subsurface. The EM surveys identified several areas of relatively high conductivity and detected a conductive plume extending to the southwest, toward the stream. This plume correlates well with the potentiometric surface and direction of ground water flow, and with water quality data from monitoring wells in and around the tailings. The electrical geophysical data suggests there has been vertical migration of high dissolved solids. A DC sounding made on a nearby granite outcrop to the north of the mine showed that the shallow conductivity is on the order of 5 millisiemens/m. Granite underlying the mine tailings, with similar electrical properties as the outcropping area, may be more than 30 meters deep.

Montana↗

Estimation of volume and mass and of changes in volume and mass of selected chat piles in the Picher mining district, Ottawa County, Oklahoma, 2005-10

From the 1890s through the 1970s the Picher mining district in northeastern Ottawa County, Oklahoma, was the site of mining and processing of lead and zinc ore. When mining ceased in about 1979, as much as 165–300 million tons of mine tailings, locally referred to as “chat,” remained in the Picher mining district. Since 1979, some chat piles have been mined for aggregate materials and have decreased in volume and mass. Currently (2013), the land surface in the Picher mining district is covered by thousands of acres of chat, much of which remains on Indian trust land owned by allottees. The Bureau of Indian Affairs manages these allotted lands and oversees the sale and removal of chat from these properties. To help the Bureau of Indian Affairs better manage the sale and removal of chat, the U.S. Geological Survey, in cooperation with the Bureau of Indian Affairs, estimated the 2005 and 2010 volumes and masses of selected chat piles remaining on allotted lands in the Picher mining district. The U.S. Geological Survey also estimated the changes in volume and mass of these chat piles for the period 2005 through 2010. The 2005 and 2010 chat-pile volume and mass estimates were computed for 34 selected chat piles on 16 properties in the study area. All computations of volume and mass were performed on individual chat piles and on groups of chat piles in the same property. The Sooner property had the greatest estimated volume (4.644 million cubic yards) and mass (5.253 ± 0.473 million tons) of chat in 2010. Five of the selected properties (Sooner, Western, Lawyers, Skelton, and St. Joe) contained estimated chat volumes exceeding 1 million cubic yards and estimated chat masses exceeding 1 million tons in 2010. Four of the selected properties (Lucky Bill Humbah, Ta Mee Heh, Bird Dog, and St. Louis No. 6) contained estimated chat volumes of less than 0.1 million cubic yards and estimated chat masses of less than 0.1 million tons in 2010. The total volume of all selected chat piles was estimated to be 18.073 million cubic yards in 2005 and 16.171 million cubic yards in 2010. The total mass of all selected chat piles was estimated to be 20.445 ± 1.840 million tons in 2005 and 18.294 ± 1.646 million tons in 2010. All of the selected chat piles decreased in volume and mass for the period 2005 through 2010. Chat piles CP022 (Ottawa property) and CP013 (Sooner property) had some within-property chat-pile redistribution, with both chat piles having net decreases in volume and mass for the period 2005 through 2010. The Sooner property and the St. Joe property had the greatest volume (and mass) changes, with 1.266 million cubic yards and 0.217 million cubic yards (1.432 ± 0.129 million tons and 0.246 ± 0.022 million tons) of chat being removed, respectively. The chat removed from the Sooner and St. Joe properties accounts for about 78 percent of the chat removed from all selected chat piles and properties. The total volume and mass removed from all selected chat piles for the period 2005 through 2010 were estimated to be 1.902 million cubic yards and 2.151 ± 0.194 million tons, respectively.

Oklahoma↗