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USGS2014

Water withdrawals, use, and trends in Florida, 2010

In 2010, the total amount of water withdrawn in Florida was estimated to be 14,988 million gallons per day (Mgal/d). Saline water accounted for 8,589 Mgal/d (57 percent) and freshwater accounted for 6,399 Mgal/d (43 percent). Groundwater accounted for 4,166 Mgal/d (65 percent) of freshwater withdrawals, and surface water accounted for the remaining 2,233 Mgal/d (35 percent). Surface water accounted for nearly all (99.9 percent) saline-water withdrawals. An additional 659 Mgal/d of reclaimed wastewater was used in Florida during 2010. Freshwater withdrawals were greatest in Palm Beach County (707 Mgal/d), and saline-water withdrawals were greatest in Hillsborough County (1,715 Mgal/d). Fresh groundwater provided drinking water (public supplied and self-supplied) for 17.33 million people (92 percent of Florida’s population), and fresh surface water provided drinking water for 1.47 million people (8 percent). The statewide public-supply gross per capita use for 2010 was 134 gallons per day, whereas the statewide public-supply domestic per capita use was 85 gallons per day. The majority of groundwater withdrawals (almost 62 percent) in 2010 were obtained from the Floridan aquifer system, which is present throughout most of the State. The majority of fresh surface-water withdrawals (56 percent) came from the southern Florida hydrologic unit subregion and is associated with Lake Okeechobee and the canals in the Everglades Agricultural Area of Glades, Hendry, and Palm Beach Counties, as well as the Caloosahatchee River and its tributaries in the agricultural areas of Collier, Glades, Hendry, and Lee Counties. Overall, agricultural irrigation accounted for 40 percent of the total freshwater withdrawals (ground and surface), followed by public supply with 35 percent. Public supply accounted for 48 percent of groundwater withdrawals, followed by agricultural self-supplied (34 percent), commercial-industrial-mining self-supplied (7 percent), recreational-landscape irrigation and domestic self-supplied (5 percent each), and power generation (less than 1 percent). Agricultural self-supplied accounted for 51 percent of fresh surface-water withdrawals, followed by power generation (25 percent), public supply (11 percent), recreational-landscape irrigation (9 percent), and commercial-industrial-mining self-supplied (4 percent). Power generation accounted for nearly all (99.8 percent) saline-water withdrawals. Of the 18.80 million people who resided in Florida during 2010, 41 percent (7.68 million people) resided in the South Florida Water Management District (SFWMD), 25 percent each resided in the Southwest Florida Water Management District (SWFWMD) and the St. Johns River Water Management District (SJRWMD) (4.73 and 4.70 million people, respectively), 7 percent (1.36 million people) resided in the Northwest Florida Water Management District (NWFWMD), and 2 percent (0.33 million people) resided in the Suwannee River Water Management District (SRWMD). The largest percentage of freshwater withdrawals was from the SFWMD (47 percent), followed by the SJRWMD (21 percent), SWFWMD (18 percent), NWFWMD (9 percent), and SRWMD (5 percent). Between 1950 and 2010, the population of Florida increased by 16.03 million (580 percent), and the total water withdrawals (fresh and saline) increased by 12,334 Mgal/d (465 percent). More recently, total freshwater withdrawals decreased by more than 1,792 Mgal/d (22 percent) between 2000 and 2010, while the population increased by 2.82 million (18 percent), and total freshwater withdrawals decreased by more than 474 Mgal/d (7 percent) between 2005 and 2010, while the population increased by 0.88 million (8 percent). The recent trend of decreases in freshwater withdrawals is a result of increased rainfall during this period, the development and use of alternative water sources, water conservation efforts, more conservative regulations and mandates, changes in economic conditions, and losses of irrigated lands. Fresh-water withdrawals for public supply, agricultural self-supplied use, and commercial-industrial-mining self-supplied use all decreased between 2000 and 2010 and between 2005 and 2010, whereas freshwater withdrawals for domestic self-supplied use, recreational-landscape irrigation use, and power generation use either remained the same or changed slightly during the decade. The use of highly mineralized groundwater (referred to as nonpotable water) as a source of drinking water has increased in Florida. Nonpotable water use for public supply has increased from nearly 2 Mgal/d in 1970 to about 165 Mgal/d in 2010. Nonpotable water is either blended or treated to meet drinking-water standards and is mostly used along the east and west coasts of central and southern Florida. The use of reclaimed wastewater increased from about 206 Mgal/d in 1986 to nearly 659 Mgal/d in 2010. More than three-quarters (79 percent) of reclaimed wastewater in 2010 was used to supplement potable-quality water withdrawals for urban irrigation, agricultural irrigation, and industrial use.

Florida↗

USGS2015

Biogeochemical aspects of uranium mineralization, mining, milling, and remediation

Natural uranium (U) occurs as a mixture of three radioactive isotopes: 238 U, 235 U, and 234 U. Only 235 U is fissionable and makes up about 0.7% of natural U, while 238 U is overwhelmingly the most abundant at greater than 99% of the total mass of U. Prior to the 1940s, U was predominantly used as a coloring agent, and U-bearing ores were mined mainly for their radium (Ra) and/or vanadium (V) content; the bulk of the U was discarded with the tailings (Finch et al., 1972). Once nuclear fission was discovered, the economic importance of U increased greatly. The mining and milling of U-bearing ores is the first step in the nuclear fuel cycle, and the contact of residual waste with natural water is a potential source of contamination of U and associated elements to the environment. Uranium is mined by three basic methods: surface (open pit), underground, and solution mining (in situ leaching or in situ recovery), depending on the deposit grade, size, location, geology and economic considerations (Abdelouas, 2006). Solid wastes at U mill tailings (UMT) sites can include both standard tailings (i.e., leached ore rock residues) and solids generated on site by waste treatment processes. The latter can include sludge or “mud” from neutralization of acidic mine/mill effluents, containing Fe and a range of coprecipitated constituents, or barium sulfate precipitates that selectively remove Ra (e.g., Carvalho et al., 2007). In this chapter, we review the hydrometallurgical processes by which U is extracted from ore, the biogeochemical processes that can affect the fate and transport of U and associated elements in the environment, and possible remediation strategies for site closure and aquifer restoration. This paper represents the fourth in a series of review papers from the U.S. Geological Survey (USGS) on geochemical aspects of UMT management that span more than three decades. The first paper (Landa, 1980) in this series is a primer on the nature of tailings and radionuclide mobilization from them. The second paper (Landa, 1999) includes coverage of research carried out under the U.S. Department of Energy’s Uranium Mill Tailings Remedial Action Program (UMTRA). The third paper (Landa, 2004) reflects the increased focus of researchers on biotic effects in UMT environs. This paper expands the focus to U mining, milling, and remedial actions, and includes extensive coverage of the increasingly important alkaline in situ recovery and groundwater restoration.

Applied Geochemistry↗

USGS1969

Physiographic, stratigraphic, and structural development of the Quadrilatero Ferrifero, Minas Gerais, Brazil

The Quadrilatero Ferrifero is an area of some 7,000 square kilometers in central Minas Gerais, Brazil centered about lat. 20°15' S, long. 43°30' W. For 250 years the region has poured forth a variety of mineral riches, now totaling more than $2 billion, and future production will undoubtedly be even greater. The main products are iron ore, manganese ore, and gold. To assist this development, the Braziliam and American Governments in 1946 jointly undertook the first detailed geologic study of the region: this report is a synthesis of the results of work and mapping by 17 Brazilian and American geologists under this program; other reports discussing the economic geology, the metamorphic geology, and the igneous geology of the region as a whole are being prepared.

Minas Gerais↗

USGS2003

Biostratigraphy and structure of paleozoic host rocks and their relationship to Carlin-type gold deposits in the Jerritt Canyon mining district, Nevada

The Jerritt Canyon mining district in the northern Independence Range, northern Nevada, contains multiple, nearly horizontal, thrust masses of platform carbonate rocks that are exposed in a series of north- to northeast-elongated, tectonic windows through rocks of the Roberts Mountains allochthon. The Roberts Mountains allochthon was emplaced during the Late Devonian to Early Mississippian Antler orogeny. These thrust masses contain structurally and stratigraphically controlled Carlin-type gold deposits. The gold deposits are hosted in tectonically truncated units of the Silurian to Devonian Hanson Creek and Roberts Mountains Formations that lie within structural slices of an Eastern assemblage of Cambrian to Devonian carbonate rocks. In addition, these multiply thrust-faulted and folded host rocks are structurally interleaved with Mississippian siliciclastic rocks and are overlain structurally by Cambrian to Devonian siliciclastic units of the Roberts Mountains allochthon. All sedimentary rocks were involved in thrusting, high-angle faulting, and folding, and some of these events indicate substantial late Paleozoic and/or Mesozoic regional shortening. Early Pennsylvanian and late Eocene dikes also intrude the sedimentary rocks. These rocks all were uplifted into a northeast-trending range by subsequent late Cenozoic Basin and Range faulting. Eocene sedimentary and volcanic rocks flank part of the range. Pathways of hydrothermal fluid flow and locations of Carlin-type gold orebodies in the Jerritt Canyon mining district were controlled by structural and host-rock geometries within specific lithologies of the stacked thrust masses of Eastern assemblage rocks. The gold deposits are most common proximal to intersections of northeast-striking faults, northwest-striking dikes, and thrust planes that lie adjacent to permeable stratigraphic horizons. The host stratigraphic units include carbonate sequences that contained primary intercrystalline permeability, which provided initial pathways for fluid flow and later served as precipitation sites for ore minerals. Alteration, during, and perhaps prior to mineralization, enhanced primary permeability by dissolution, by removal of calcite, and by formation of dolomite. Ore-stage sulfide minerals and alteration minerals commonly precipitated in pore spaces among dolomite grains. Microveinlets and microbrecciation in zones of intense alteration also provided networks of secondary permeability that further enhanced fluid flux and produced additional sites for ore deposition.

Economic Geology↗

USGS1960

Pumice and pozzolan deposits in the Lesser Antilles

Early in 1959 the International Cooperation Administration requested the U. S. Geological Survey to assign a geologist to a reconnaissance study of the pumice and pozzolan deposits of the Lesser Antilles. As a result, I made brief field examinations of all the reported deposits during the period May 25 - June 23, 1959. In company with Mr. Peter Martin-Kaye, Government Geologist, Windward Islands, headquartered at Castries, St. Lucia, I examined potential pumice and pozzolan deposits in Grenada, Dominica, St. Vincent and St. Lucia. With Dr. Percy C. Henriquez of the Technical-Economic Council, Netherlands Antilles, headquartered in Curacao, I saw those of St. Eustatius. I also visited pumice deposits on Martinique, in company with Mr. Edward T. Foster, Vice President of Meekins West Indies Company of Hollywood, Fla. Short visits were made to the islands of Antigua, Barbados, Nevis, St. Kitts, and Trinidad, partly to meet the necessities of inter-island transportation and partly to get some idea of the actual or potential mineral resources of these islands.

Open-File Report↗

USGS1976

Diamond drilling at the Ma'milah Mine, Kingdom of Saudi Arabia

The Ma'millah gold mine is about 90 km southeast of At Ta'if at lat 21°03'N., long 41°18'E., in southwestern Saudi Arabia. The deposit, which was worked extensively by ancient miners, consists of several veins and massive lenses of quartz along a regional fault. The extensive ancient mine workings, large size of some quartz outcrops, and significant gold content of several samples indicated that subsurface exploration was warranted. Accordingly, two holes were drilled into the deposit during the interval December 1972 to February 1973. The drill findings were disappointing; the grade of vein material was found to be too low to be of economic interest and the quartz bodies were found to pinch out both along strike and downdip. The drilling program therefore was terminated. The deposit is not worth further exploration

Ma'milah Mine↗

USGS2025

Formation of the Mount Weld rare earth deposit, Western Australia: Geochronology constraints

Constraining the age of protracted chemical weathering in stable cratonic areas that may form thick regoliths and the potential enrichment of various elements is challenging. Economic deposits of aluminium, iron, copper, nickel, cobalt, niobium, and rare earth elements (REEs) form in this manner. Determining the age of formation can provide key information for exploration of similar deposits as well as to better constrain paleoclimatic conditions. This study describes our effort to constrain the age of formation of the Mount Weld deposit, a world-class carbonatite-derived REE laterite deposit. We utilize multiple geochronological techniques on different minerals. The oldest dates, ranging from ca. 100 to 50 Ma, were from laser ablation ICPMS, Lu-Hf dating of churchite, a heavy REE phosphate mineral formed by mineral saturation in groundwater. Growth bands on individual minerals show a younging outwards. 40 Ar/ 39 Ar geochronology of cryptomelane, a potassium-bearing manganese oxide mineral, yielded ages ranging from ca. 40 to 26 Ma. Similarly, (U–Th)/He geochronology of goethite yielded ages from ca. 45 to 19 Ma.

Mount Weld deposit↗

USGS1950

Value of domestic production of minerals from various classes of rocks

Fluids and sedimentary rocks accounted for 48 and 36 percent, respectively, of the total value of the 1946 domestic mineral production. The epigenetic (vein and replacement) and metamorphic deposits each contributed 6 percent of the total, and residual and igneous deposits accounted for 3 and 1 percent, respectively. Fuels were the most valuable of all the minerals produced--77 percent of the total. Petroleum, natural gas, and similar fluid fuels accounted for 47 percent of the total production and 98 percent of that from fluids; bituminous coal made up 24 percent of the total production and 67 percent of that from sedimentary rocks; anthracite coal was valued at 6 percent of the total production and 92 percent of that from metamorphic rocks. Exclusive of fuels, the bulk of the production of nonmetallics, and of the total mineral production too, was from sedimentary rocks (74 and 50 percent, respectively) and from veins and replacements (8 and 28 percent, respectively). Most of the production of metals, however, was from veins, etc. (62 percent) and residuum (29 percent).

Economic Geology↗

USGS1965

Electrochemical geothermometer: A possible new method of geothermometry with electro-conductive minerals

It was demonstrated with artificially processed sulfides that the minimum temperature of equilibration of a pair of electro - conductive minerals can be determined electrochemically. The procedure consists of setting up an electrochemical cell with the mineral electrodes and a suitable electrolyte, changing the temperature of the cell slowly in a furnace, and finding the temperature at which the emf of the cell becomes zero. The experimental results strongly suggest that this electrochemical method could be used as a new method of geothermometry .

Economic Geology↗

USGS1984

Government investment in mineral resource information on leasable public lands: The case of strippable coal

A scheme is presented to aid the government in estimating the net benefits, in terms of itsrecovery of expected rents, of performing various levels of exploration of mineral tracts prior to leasing and making such information available to potential bidders. Conditions are identified where the government will profit by investment in geologic data that are collected and provided to potential bidders without reducing the expected returns to bidders. Expected benefits of an optimal data-collection program depend on (1) the degree of bidder risk aversion, (2) the expected degree of lease competition and (3) unique lease tract factors that determine economic rents—thickness of seams, proximity to markets, extraction costs, and the spatial correlation characteristics of data. The effects of price uncertainty and government policies affecting market stability on the value of information are also discussed.

Resources and Energy↗

USGS2004

Formation of a paleothermal anomaly and disseminated gold deposits associated with the Bingham Canyon porphyry Cu-Au-Mo system, Utah

The thermal history of the Oquirrh Mountains, Utah, indicates that hydrothermal fluids associated with emplacement of the 37 Ma Bingham Canyon porphyry Cu-Au-Mo deposit extended at least 10 km north of the Bingham pit. An associated paleothermal anomaly enclosed the Barneys Canyon and Melco disseminated gold deposits and several smaller gold deposits between them. Previous studies have shown the Barneys Canyon deposit is near the outer limit of an irregular distal Au-As geochemical halo, about 3 km beyond an intermediate Pb-Zn halo, and 7 km beyond a proximal pyrite halo centered on the Bingham porphyry copper deposit. The Melco deposit also lies near the outer limit of the Au-As halo. Analysis of several geothermometers from samples collected tip to 22 km north of the Bingham Canyon porphyry Cu-Au-Mo deposit indicate that most sedimentary rocks of the Oquirrh Mountains, including those at the gold deposits, have not been regionally heated beyond the "oil window" (less than about 150??C). For geologically reasonable heating durations, the maximum sustained temperature at Melco, 6 km north of the Bingham pit, and at Barneys Canyon, 7.5 km north of the pit, was between 100??C and 140??C, as indicated by combinations of conodont color alteration indices of 1.5 to 2, mean random solid bitumen reflectance of about 1.0 percent, lack of annealing of zircon fission tracks, and partial to complete annealing of apatite fission tracks. The pattern of reset apatite fission-track ages indicates that the gold deposits are located approximately on the 120??C isotherm of the 37 Ma paleothermal anomaly assuming a heating duration of about 106 years. The conodont data further constrain the duration of heating to between 5 ?? 104 and 106 years at approximately 120??C. The ??18O of quartzite host rocks generally increases from about 12.6 per mil at the porphyry to about 15.8 per mil approximately 11 km from the Bingham deposit. This change reflects interaction of interstitial clays in the quartzite with circulating meteoric water related to the Bingham Canyon porphyry system. The ??18O and ??13C values of limestone vary with respect to degree of recrystallization and proximity to open fractures. Recrystallized limestone at the Melco and Barneys Canyon gold deposits has the highest ??18O values (about 30???), whereas limestone adjacent to the porphyry copper deposit has the lowest values (about 10???). The high ??18O values for the recrystallized limestone at Barneys Canyon and Melco strongly suggest that mineralization was related to low temperature fluids with exceptionally high ??18OH2O values such as could be derived from water in a crater lake of an active volcano. The age of formation of the gold deposits has been interpreted to range from Jurassic to Eocene. The mineralized rocks at the Barneys Canyon and Melco deposits are likely the same age as the geochemically similar deposits that are present in north-striking, late faults that cut the Bingham Canyon porphyry. The patterns of apatite and zircon fission-track data, conodont color alteration indices, solid bitumen reflectivity, stable isotope data, and mineral zoning are consistent with the gold deposits being genetically related to formation of the 37 Ma Bingham porphyry deposit. We interpret the disseminated gold mineralization to be related to collapse of the Bingham Canyon hydrothermal system in which isotopically heavy, oxidizing, acidic waters, possibly from an internally draining acidic crater lake, mixed with and were entrained into reduced gold-bearing meteoric water fluids in the collapsing main-stage hydrothermal system. Most of this fluid mixing and cooling was probably located close to the hydrologic interface between the sedimentary basement rocks and overlying volcanic rocks. ??2004 by Economic Geology.

Economic Geology↗

USGS2020

Genesis and evolution of ferromanganese crusts from the summit of Rio Grande Rise, southwest Atlantic Ocean

The Rio Grande Rise (RGR) is a large elevation in the Atlantic Ocean and known to host potential mineral resources of ferromanganese crusts (Fe–Mn), but no investigation into their general characteristics have been made in detail. Here, we investigate the chemical and mineralogical composition, growth rates and ages of initiation, and phosphatization of relatively shallow-water (650–825 m) Fe–Mn crusts dredged from the summit of RGR by using computed tomography, X-ray diffraction, 87 Sr/ 86 Sr ratios, U–Th isotopes, and various analytical techniques to determine their chemical composition. Fe–Mn crusts from RGR have two distinct generations. The older one has an estimated age of initiation around 48–55 Ma and was extensively affected by post-depositional processes under suboxic conditions resulting in phosphatization during the Miocene (from 20 to 6.8 Ma). As a result, the older generation shows characteristics of diagenetic Fe–Mn deposits, such as low Fe/Mn ratios (mean 0.52), high Mn, Ni, and Li contents and the presence of a 10 Å phyllomanganate, combined with the highest P content among crusts (up to 7.7 wt %). The younger generation is typical of hydrogenetic crusts formed under oxic conditions, with a mean Fe/Mn ratio of 0.75 and mean Co content of 0.66 wt %, and has the highest mean contents of Bi, Nb, Ni, Te, Rh, Ru, and Pt among crusts formed elsewhere. The regeneration of nutrients from local biological productivity in the water column is the main source of metals to crusts, providing mainly metals that regenerate rapidly in the water column and are made available at relatively shallow water depths (Ni, As, V, and Cd), at the expense of metals of slower regeneration (Si and Cu). Additionally, important contributions of nutrients may derive from various water masses, especially the South Atlantic Mode Water and Antarctic Intermediate Water (AAIW). Bulk Fe–Mn crusts from the summit of RGR plateau are generally depleted in metals considered of greatest economic interest in crusts like Co, REE, Mo, Te, and Zr, but are the most enriched in the critical metals Ni and Li compared to other crusts. Further investigations are warranted on Fe–Mn crusts from deeper-water depths along the RGR plateau and surrounding areas, which would less likely be affected by phosphatization.

Rio Grande Rise↗

USGS2016

U-Pb, Re-Os, and Ar/Ar geochronology of rare earth element (REE)-rich breccia pipes and associated host rocks from the Mesoproterozoic Pea Ridge Fe-REE-Au deposit, St. Francois Mountains, Missouri

Rare earth element (REE)-rich breccia pipes (600,000 t @ 12% rare earth oxides) are preserved along the margins of the 136-million metric ton (Mt) Pea Ridge magnetite-apatite deposit, within Mesoproterozoic (~1.47 Ga) volcanic-plutonic rocks of the St. Francois Mountains terrane in southeastern Missouri, United States. The breccia pipes cut the rhyolite-hosted magnetite deposit and contain clasts of nearly all local bedrock and mineralized lithologies. Grains of monazite and xenotime were extracted from breccia pipe samples for SHRIMP U-Pb geochronology; both minerals were also dated in one polished thin section. Monazite forms two morphologies: (1) matrix granular grains composed of numerous small (<50 μ m) crystallites intergrown with rare xenotime, thorite, apatite, and magnetite; and (2) coarse euhedral, glassy, bright-yellow grains similar to typical igneous or metamorphic monazite. Trace element abundances (including REE patterns) were determined on selected grains of monazite (both morphologies) and xenotime. Zircon grains from two samples of host rhyolite and two late felsic dikes collected underground at Pea Ridge were also dated. Additional geochronology done on breccia pipe minerals includes Re-Os on fine-grained molybdenite and 40 Ar/ 39 Ar on muscovite, biotite, and K-feldspar. Ages (±2 σ errors) obtained by SHRIMP U-Pb analysis are as follows: (1) zircon from the two host rhyolite samples have ages of 1473.6 ± 8.0 and 1472.7 ± 5.6 Ma; most zircon in late felsic dikes is interpreted as xenocrystic (age range ca. 1522–1455 Ma); a population of rare spongy zircon is likely of igneous origin and yields an age of 1441 ± 9 Ma; (2) pale-yellow granular monazite—1464.9 ± 3.3 Ma (no dated xenotime); (3) reddish matrix granular monazite—1462.0 ± 3.5 Ma and associated xenotime—1453 ± 11 Ma; (4) coarse glassy-yellow monazite—1464.8 ± 2.1, 1461.7 ± 3.7 Ma, with rims at 1447.2 ± 4.7 Ma; and (5) matrix monazite (in situ)—1464.1 ± 3.6 and 1454.6 ± 9.6 Ma, and matrix xenotime (in situ)—1468.0 ± 8.0 Ma. Two slightly older ages of cores are about 1478 Ma. The young age of rims on the coarse glassy monazite coincides with an Re-Os age of 1440.6 ± 9.2 Ma determined in this study for molybdenite intergrown with quartz and allanite, and with the age of monazite inclusions in apatite from the magnetite ore ( Neymark et al., 2016 ). A 40 Ar/ 39 Ar age of 1473 ± 1 Ma was obtained for muscovite from a breccia pipe sample. Geochronology and trace element geochemical data suggest that the granular matrix monazite and xenotime (in polygonal texture), and cores of coarse glassy monazite precipitated from hydrothermal fluids during breccia pipes formation at about 1465 Ma. The second episode of mineral growth at ca. 1443 Ma may be related to faulting and fluid flow that rebrecciated the pipes. The ca. 10-m.y. gap between the ages of host volcanic rocks and breccia pipe monazite and xenotime suggests that breccia pipe mineral formation cannot be related to the felsic magmatism represented by the rhyolitic volcanic rocks, and hence is linked to a different magmatic-hydrothermal system.

Missouri↗

USGS1975

Geochemical studies in the Park City district; II, Sulfide mineralogy and minor-element chemistry, Mayflower mine

Fissure-filling and replacement Pb-Zn-Cu-Au-Ag ores of the Mayflower mine occur in calcareous sedimentary and intrusive wall rocks over a vertical interval of 3,000 feet. The ores are exceptional in the district for their chalcopyrite and gold content and for the unusual associated gangue minerals anhydrite, chlorite, and hematite. High oxygen fugacities are indicated for many stages of mineralization. Sphalerite compositions are highly variable in the range 0.09 to 5.9 weight percent Fe, an indication of large fluctuations in sulfur fugacity. Silver is carried in tetrahedrite-tennantite (0.2 to 16 wt %), enargite (0.5 to 0.8 wt %), in coupled substitution with Bi + Sb in galena (0.02 to 2.9 wt %), and in the minerals argentite, matildite, chalcocite, and bornite. Content of As, Se, Te, and other minor elements is small. Fractionation of Cd between sphalerite and coexisting galena is relatively consistent whereas the fractionation of Mn between sphalerite and galena is variable; calculated temperatures of formation are high and unreliable.

Economic Geology↗

USGS2026

Quantitative mineral resource assessment of lithium pegmatite deposits in the southern Appalachian orogen

The first quantitative mineral resource assessment for undiscovered lithium pegmatite deposits in the southern Appalachian region of the United States was conducted. Permissive tracts for lithium pegmatite deposits were delineated by integrating lithological, tectonic, geochemical, geophysical and mineral occurrence data. Lithium pegmatite prospectivity of the tracts was ranked with simplified mappable criteria, including proximity to Paleozoic felsic intrusions and major lithotectonic structures, stream sediment geochemical anomalies, and pegmatite occurrence data. The geospatial data and permissive tracts were used to estimate the number of undiscovered lithium pegmatite deposits. These estimates were integrated into probabilistic simulations along with a new global lithium pegmatite grade and tonnage dataset to quantify potential contained undiscovered lithium resources. An economic filter was applied to convert the probabilistic estimates of contained lithium into recoverable material. The identified lithium pegmatite resources for the Carolina Lithium and Kings Mountain deposits, North Carolina, contain 1589 thousand tons (kt) of Li 2 O. The median contained undiscovered resource for the southern Appalachian orogen was estimated to be 2240 kt Li 2 O. At 90% confidence, the region contains at least 130 kt Li 2 O, and 10,700 kt at 10% confidence. After applying economic filters, the median recoverable contained resource was 1430 kt Li 2 O, corresponding to approximately 201 years of current lithium imports for consumption in the United States. North and South Carolina are likely to contain most of these resources. Coarse data resolution and intra-state variations in the geological data contribute to uncertainty of undiscovered lithium pegmatite resources. Continued efforts to harmonize disparate geospatial datasets with updated or new information can improve the accuracy and precision of estimated undiscovered lithium pegmatite resources in the study area and at broader scales.

Alabama, Georgia, Maryland, North Carolina, South ↗

USGS2019

Demonstrating the value of Earth observations—methods, practical applications, and solutions—group on Earth observations side event proceedings

Executive Summary The U.S. Geological Survey, the National Oceanic and Atmospheric Administration, the European Association for Remote Sensing Companies, and the European Space Agency in coordination with the GEOValue Community hosted a side event to the Group on Earth Observations Plenary on October 23–24, 2017, in Washington, D.C. The workshop, entitled “Demonstrating the Value of Earth Observations: Methods, Practical Applications and Solutions,” brought together more than 60 international experts including economists, scientists, and engineers to consider the state of the science and applications of valuing Earth observations (EO). This 2-day workshop built upon previous activities developed under the GEOValue initiative. This workshop brought together expert analysts from multiple disciplines and backgrounds who are developing methods to identify and measure the value of information generated from the use of satellite and in-situ data. The mix of government agencies, international financial institutions, and independent consultants who participated in the workshop blended to develop a rich mix of views, approaches, and outcomes. During the first part of the workshop, the focus was on the latest science in valuing EO. A number of methodologies were described. Approaches generally assess the societal benefits of specific actions (for example, investments in EO). Some methods focus on broad measures of economic activity (for example, gross domestic product) or methods to assess total economic value such as contingent valuation surveys. Alternatively, use-case approaches (a use case is defined as an evaluation in which one or more decisions, applications, or other uses of data, information, and information products are specifically considered) start with the specific actions and how information is used to support decision making and affect outcomes. The second part of the meeting was focused on the use and development of value chains and decision trees. A value chain can be defined as the set of value-adding activities that one or more organizations perform in creating and distributing goods and services. In terms of EO, the value chain approach can be applied to consider societal benefits of the data and assess the value of data and data features. The EO value chain considers the geospatial data sources and the processing of the data into value added information to be incorporated into decision-support systems, leading to decision makers’ actions. To understand the value of EO, one would also need to recognize the demand side of the equation or how EO benefits users. Extending the value chain concept and incorporating tenets of Bayesian decision making, a decision tree would include one or more use cases. The value provided by the marginal increase in information could flow from one or several parts of the supply side of the value chain. The decision tree is based on the premise that information has no value if it is not used in at least one decision. By connecting the value chain and the decision tree, a framework is created that allows for conceptualizing the value of EO in its many uses. One can then apply economic techniques to monetize the marginal benefit of an outcome with information versus one without. A third part of the meeting applied the value chain and decision-tree frameworks to five specific thematic areas, each with the focus of using information for a decision point: Effect of increasing temperatures on human health; Flooding—Mitigating, managing, and avoiding impacts to safety and property damage; Harmful algal blooms—Effects on human health, recreation, and tourism; Energy and mineral supply—Mitigating, managing, and avoiding impacts of shortfalls on the economy; and Effects of natural hazards on transportation systems—Effects on mobility, safety, and the economy. During the working session, five separate groups worked to define and delineate the value chains and decision trees associated with each topic, discussing the related challenges and data needs. The outcomes were reported back to the full group. Because of the complexity of the topics, most groups first identified a network of value chains and then narrowed the scope to develop a single value chain to address their group’s topic. Although they worked separately and on different topics, the groups came to similar conclusions, concurring that the value chain and decision-tree frameworks are very effective for informing quantitative impact assessments and developing a relatable narrative to assist the public in understanding the link between EO and citizens.

Open-File Report↗

USGS1991

Simplified cost models for prefeasibility mineral evaluations

In this U.S. Bureau of Mines report, mine and mill cost models are presented to make quick estimates of the cost to develop mineral deposits in the desert region of the Southwest United States. Regression analysis was used to generate capital and operating cost equations for each model in the form Y = AX', where Y is the cost estimated and X is the assumed daily capacity in short tons. A and B are constants determined by the regression analysis. Each is broken down into 11 subcategories to facilitate escalation of costs for inflation and to increase their versatility in economic evaluation work. This report contains 2 open pit models, 6 underground mine models, 11 mill models, and cost equations for access roads, power lines, and tailings ponds. In addition, adjustment factors for variation in haulage distances are provided for open pit models and variation in mining depths for underground models.

Information Circular↗

USGS1953

Reconnaissance for radioactive materials in northeastern United States during 1952

Reconnaissance for radioactive materials was made in parts of Maine, New York, New Jersey, and Pennsylvania. The primary objective was to examine the iron ore deposits and associated rocks in the Adirondack Mountains of New York and the Highlands of New Jersey. In addition, several deposits known or reported to contain radioactive minerals were examined to delimit their extent. Most of the deposits examined are not significant as possible sources of radioactive elements and the data pertaining to them are summarized in table form. Deposits that do warrant more description than can be given in table form are: Benson Mines, St. Lawrence County, N. Y.; Rutgers mine, Clinton County, N. Y.; Mineville Mines, Essex County, N. Y.l Canfield phosphate mine, Morris County, N. J.; Mullgan quarry, Hunterdon County, N. J.; and the Chestnut Hill-Marble Mountain area, Pennsylvania and New Jersey. The Old Bed in the Mineville district is the only deposit that may be economically significant. Apatite from Old Bed ore contains as much as 4.9 percent total rare earth. 0.04 percent thorium, and 0.018 percent uranium. Magnetite ore at the Rutgers mine contains radioactive zircon and apatite. Radioactivity measurements of outcrops and dump material show that the ore contains from 0.005 to 0.010 percent equivalent uranium. One sample of lean magnetite ore contains 0.006 percent equivalent uranium. Garnet-rich zones in the Benson Mines magnetite deposit contain as much as 0.017 equivalent uranium. Most of the rock and ore, however, contains about 0.005 percent equivalent uranium. Available data indicate that the garnet-rich zones are enriched in radioactive allanite. A shear zone in the Kittatinny limestone of Cambrian age at the Mulligan quarry contains uraniferous material. Radioactivity anomalies elsewhere in the quarry and in adjacent fields indicate that there may be other uraniferous shear zones. Assays of samples and measurements of outcrop radioactivity indicate that the uranium content of these zones is low; samples contain from 0.008 to 0.068 percent equivalent uranium. The anomalies, however, may indicate greater concentrations of uranium below surficial leached zones. The Chestnut Hill-Marble Mountain area contains radioactivity anomalies for about 2 miles along the strike of the contact of pre-Cambrian Pickering gneiss and Franklin limestone formations. In places this contact is injected with pegmatite, which probably was the source of the radioelements. The most favorable area for further study is at Marble Mountain, where a nearly continuous anomaly extends for about 1500 feet. Samples from part of this area contain as much as 0.044 percent equivalent uranium and 0.005 percent uranium. Radioactive hematite and florencite, in which thorium may have substituted for cerium, are the only radioactive minerals observed in the Marble Mountain area.

New Jersey;New York;Pennsylvania↗