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At least 307 records · Page 17Linked to original sources
USGS2017

Trawl-based assessment of Lake Ontario pelagic prey fishes including Alewife and Rainbow Smelt

Managing Lake Ontario fisheries in an ecosystem-context, requires reliable data on the status and trends of prey fishes that support predator populations. We report on the community and population dynamics of Lake Ontario pelagic prey fishes, based on bottom trawl surveys. We emphasize information that supports the international Lake Ontario Committee’s Fish Community Objectives. In 2016, 142 bottom trawls were collected in U.S. waters, and for the first time 46 trawls were conducted in Canadian waters. A total of 420,386 fish from 24 species were captured. Alewife were 89% of the total fish catch and 93% of the pelagic prey fish catch. The Rainbow Smelt abundance index in U.S. waters increased slightly in 2016 relative to 2015. Interestingly, the Rainbow Smelt abundance index from tows in Canadian waters was 35% higher than the U.S. index. Abundances of Threespine Stickleback and Emerald Shiners in both U.S. and Canadian waters were low in 2016 relative to their peak abundances in the late 1990s, but Cisco abundance indices suggest a recent increase in their abundance. This year, the reported Alewife abundance time series was truncated to only include values since 1997, which were collected with the same trawl and eliminated the need to adjust values for different trawls. The 2016 adult Alewife abundance index was the second lowest abundance ever observed in the time series. This value was expected to decline from the 2015 value since the indices of juvenile Alewife were low in 2014 and the lowest ever observed in 2015. The fall condition index of adult Alewife increased in 2016 and is consistent with lower abundance and reduced competition for zooplankton resources. The 2016 Age-1 Alewife index increased relative to 2014 and 2015, and suggested lake conditions were favorable for Age-1 survival and growth during the summer of 2015 and the 2015-2016 winter. Interestingly, the catch of adult and Age1 Alewife was higher in trawls conducted in Canadian waters relative to U. S. waters. The larger trawl catches in Canadian waters suggest there may be important spatial differences in lake-wide distribution of prey fishes in April when trawling is conducted. Future surveys should to continue to sample at the whole-lake scale to understand the year to year variability in spatial distribution and the physical or biotic factors driving those distribution differences.

Report↗
USGS2008

Petrographic and Vitrinite Reflectance Analyses of a Suite of High Volatile Bituminous Coal Samples from the United States and Venezuela

This report presents vitrinite reflectance and detailed organic composition data for nine high volatile bituminous coal samples. These samples were selected to provide a single, internally consistent set of reflectance and composition analyses to facilitate the study of linkages among coal composition, bitumen generation during thermal maturation, and geochemical characteristics of generated hydrocarbons. Understanding these linkages is important for addressing several issues, including: the role of coal as a source rock within a petroleum system, the potential for conversion of coal resources to liquid hydrocarbon fuels, and the interactions between coal and carbon dioxide during enhanced coalbed methane recovery and(or) carbon dioxide sequestration in coal beds.

Open-File Report↗
USGS2008

Report of the Federal Advisory Committee on the Bird Banding Laboratory

In the fall of 2005, the Directors of the U.S. Geological Survey (USGS) and the U.S. Fish and Wildlife Service (FWS) determined that to ensure that the Bird Banding Laboratory (BBL) of the USGS maintains and continues its important support of conservation and management of birds, it should be guided by a clear vision for the future. In order to carry out this task, they impaneled a fourteen-member Federal Advisory Committee (FAC) on the Bird Banding Laboratory. It was made up of representatives of the broad bird-banding community, public and private, and was cochaired by a senior representative from each agency. The Committee met four times and a writing subgroup met three times over the course of its work. The Committee identified a new vision and mission for the BBL and identified six goals that it believes should be integral to the development of a strategic plan to achieve them. Those goals are: 1. Facilitate the identification of individual birds through marking. 2. Create automated, electronic systems that efficiently verify, accept, store, and manage data associated with individually marked birds. 3. Facilitate access to and use of data from marked birds for science, conservation, and management. 4. Administer permits in an efficient, timely, and modern manner, and use them to ensure that bird welfare and data quality remain top priorities. 5. Work closely with national and international partners to achieve the mission of the BBL. 6. Manage the BBL in an efficient, cost-effective manner to maximize use of available resources. Most of the report is structured around these goals. The Committee made 2 programmatic recommendations and identified 23 objectives and 58 specific recommendations. The programmatic recommendations are: (1) that the primary role of the BBL is and should continue to be to support the use of banding and banding data by researchers and managers engaged in science, conservation, and management of birds, and not to play a lead role in original research; and (2) that the BBL be managed nationally by USGS headquarters as a research and operational support unit and provided with the resources appropriate to its national and international functions and responsibilities; it should continue to be located physically at the Patuxent Wildlife Research Center (PWRC). In order to achieve its vision and mission, the Committee believes that the BBL must work towards achieving all of the recommendations in this report. Nevertheless, it identified five objectives that stand out as high priority, and they are as follows: *Objective 1.1?to ensure a continuing, adequate supply of high-quality, Federally issued numeric bands of required sizes, materials, and types; *Objective 2.1?to improve mechanisms for verifying, accepting, storing, and managing bird-banding data; *Objective 2.3?to accommodate recapture data; *Objective 4.1?to ensure through the permitting process that banders know how to safely handle birds, collect data accurately, and maintain birds in humane and healthful conditions; and *Objective 5.3?to encourage the development of banding programs in Latin America and the Caribbean. Finally, this Committee believes that the BBL will be well served if it continues to support a Federal Advisory Committee, composed similarly to this one, to continue offering guidance and direction from the broad bird-banding community.

Circular↗
USGS2008

The Virtual Data Center Tagged-Format Tool: Introduction and executive summary

This Report introduces and summarizes the new Virtual Data Center (VDC) Tagged Format (VTF) Tool, which was developed by a diverse group of seismologists, earthquake engineers, and information technology professionals for internal use by the COSMOS VDC and other interested parties for the exchange, archiving, and analysis of earthquake strong-ground-motion data.

Open-File Report↗
USGS1998

Catalog of the historically active volcanoes of Alaska

Alaska hosts within its borders over 80 major volcanic centers that have erupted during Holocene time (< 10,000 years). At least 29 of these volcanic centers (table 1) had historical eruptions and 12 additional volcanic centers may have had historical eruptions. Historical in Alaska generally means the period since 1760 when explorers, travelers, and inhabitants kept written records. These 41 volcanic centers have been the source for >265 eruptions reported from Alaska volcanoes. With the exception of Wrangell volcano, all the centers are in, or near, the Aleutian volcanic arc, which extends 2500 km from Hayes volcano 145 km west of Anchorage in the Alaska-Aleutian Range to Buldir Island in the western Aleutian Islands (fig. 1). The volcanic arc, a subduction-related feature associated with underthrusting of the Pacific plate beneath the North American plate is divided between oceanic island arc and continental margin segments, the boundary occurring at about 165° W longitude (fig. 1). An additional 7 volcanic centers in the Aleutian arc (table 2; fig. 1 A) have active fumarole fields but no reported historical eruptions. This report discusses the location, physiography and structure, eruptive history, and geology of those volcanoes in Alaska that have experienced one or more eruptions that have been recorded in the written history (i.e., in historical time). It is part of the group of catalogs entitled Catalogue of Active Volcanoes of the World published beginning in 1951 under the auspices of the International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI). A knowledge of the information contained in such catalogs aids in understanding the type and scale of activity that might be expected during a particular eruption, the hazards the eruption may pose, and even the prediction of eruptions. The catalog will thus be of value not only to the inhabitants of Alaska but to government agencies concerned with emergency response, air traffic operations, and weather, as well as to industry and scientists. The combination of the hazard posed by volcanic ash to jet aircraft and the heavy use of international air routes located parallel to, and on either side of, the Aleutian volcanic arc means that even remote volcanoes in Alaska now pose significant hazards to life and property. Although this report is concerned with historical eruptions from Alaskan volcanoes, other volcanoes in Alaska have erupted in the past 10,000 years and might therefore be expected to erupt again. Several Holocene volcanic centers in the Aleutian arc have no reported historical activity. Elsewhere in Alaska the Bering Sea basalt fields cover large areas of the Yukon Delta, Seward Peninsula, and several of the islands of the Bering Sea. Holocene centers also occur in the Wrangell Mountains and in isolated occurrences in the interior and southeastern Alaska. Eruptions from these centers have occurred within the past several hundred years but none were transcribed in the written record. Moodie and others (1992), however, report oral traditions among the Northern Athapaskan Indians of the southwestern Yukon Territory that may record the second and younger deposition of the White River Ash circa A.D. 720. This lobe of the White River Ash was deposited during the paroxysmal eruption of Churchill volcano in the Wrangell Mountains of eastcentral Alaska (McGimsey and others, 1992; Richter and others, 1995).

Alaska↗
USGS2007

Input, flux, and persistence of six select pesticides in San Francisco Bay

Temporal patterns of pesticide inputs to San Francisco Bay were identified and correlated with timing of application and transport mechanism. Fluxes were calculated from measured concentrations and estimated flow. Persistence of the pesticides under typical riverine or estuarine conditions were estimated from laboratory experiments. Simazine was detected most frequently and had the highest flux into the Bay, which could be explained by its continuous use and long half-life. In comparison, diazinon was detected at lower concentrations and had a lower flux which corresponded to its lower use and shorter half-life. The order-of-magnitude lower fluxes of carbofuran and methidathion corresponded to their lower use and expected hydrolysis. Molinate was detected at the highest concentration but its flux was lower than expected, considering its very high use and persistence in the laboratory experiments. Additional loss of molinate is likely to occur from volatilization and photodegradation on the rice fields. Although thiobencarb had the second highest use, it had the lowest flux of the six pesticides, which can be attributed to its loss via hydrolysis, photodegradation, volatilization, and sorption to sediments. Fluxes into San Francisco Bay were equal to or greater than those reported for other estuaries, except for the Gulf of Mexico.

California↗
USGS1980

Additional studies of competition and performance in OCS oil and gas sales, 1954-1975

Economic rent is commonly defined in economics as any payment to a factor of production in excess of the minimum necessary to engage it in production. In the case of OCS lands owned by the federal government, the minimum supply price necessary to induce the federal government to lease production rights would be the costs of establishing and administering lease contracts. Assuming, for the sake of simplicity, that these costs are small enough to be ignored in the analysis, all payments to the federal government for use of OCS lands are forms of economic rent. An ideal leasing system should transfer the full amount of economic rent implicit in OCS resources to the federal government. Whether such a complete transfer of economic rent occurs depends upon the conditions of competition in the market for OCS leases. The principal means for capturing economic rent under the bidding system employed by the federal government over the years 1954-1969 are the bonus paid by the highest bidder and a royalty payment which has historically been fixed at 16 2/3 percent of gross production value. Of less importance is an annual rental payment, usually about \$3.00 per acre, which is paid as long as a tract under lease is not producing. In the sections which follow, major factors affecting the capture of economic rent by the federal government are discussed and data are presented which demonstrate the importance of the different means used. In computing the amounts of economic rent captured by the federal government, the discounted cash flow technique is employed. This requires selection of an appropriate discount rate, in contrast to the internal rate of return analysis used in Part I, above.

Report↗
USGS2007

Climate Change Research at USGS Center for Earth Resources Observation and Science (EROS)

Research and development projects at EROS apply unique resources to support the USGS mission of developing understanding, monitoring, and modeling of climate variability and change and their human, physical, and biological impacts. Remote sensing resources, both new and archived, form the core of our ability to determine changes in the state or condition of the Earth’s surface and its dynamic landscape and ecosystem processes. This rich resource provides powerful biophysical information for local to global areas. Archival data form the basis for assessing human and climate impacts on the land surface, trends of land use, and an understanding of climate and management impacts. Biophysical information from satellite data is assimilated into quantitative models that allow all disciplines of the USGS to understand impacts on ecosystem processes. Major processes and problems we address include: carbon fluxes, hydrological processes, albedo changes and regional climates, mangroves and wetland protection of coastal environments, natural and manmade hazards (e.g., fire and drought), ecosystem change and succession, land use and land cover change, and more. The integration of remote sensing, modeling, and multidisciplinary approaches fosters international scientific leadership across all disciplines for the USGS.

Fact Sheet↗
USGS2015

Climate change: evaluating your local and regional water resources

The BCM is a fine-scale hydrologic model that uses detailed maps of soils, geology, topography, and transient monthly or daily maps of potential evapotranspiration, air temperature, and precipitation to generate maps of recharge, runoff, snow pack, actual evapotranspiration, and climatic water deficit. With these comprehensive environmental inputs and experienced scientific analysis, the BCM provides resource managers with important hydrologic and ecologic understanding of a landscape or basin at hillslope to regional scales. The model is calibrated using historical climate and streamflow data over the range of geologic materials specific to an area. Once calibrated, the model is used to translate climate-change data into hydrologic responses for a defined landscape, to provide managers an understanding of potential ecological risks and threats to water supplies and managed hydrologic systems. Although limited to estimates of unimpaired hydrologic conditions, estimates of impaired conditions, such as agricultural demand, diversions, or reservoir outflows can be incorporated into the calibration of the model to expand its utility. Additionally, the model can be linked to other models, such as groundwater-flow models (that is, MODFLOW) or the integrated hydrologic model (MF-FMP), to provide information about subsurface hydrologic processes. The model can be applied at a relatively small scale, but also can be applied to large-scale national and international river basins.

Fact Sheet↗
USGS2000

Data for Quaternary faults, liquefaction features, and possible tectonic features in the Central and Eastern United States, east of the Rocky Mountain Front

The USGS is currently leading an effort to compile published geological information on Quaternary faults, folds, and earthquake-induced liquefaction in order to develop an internally consistent database on the locations, ages, and activity rates of major earthquake-related features throughout the United States. This report is the compilation for such features in the Central and Eastern United States (CEUS), which for the purposes of the compilation, is defined as the region extending from the Rocky Mountain Front eastward to the Atlantic seaboard. A key objective of this national compilation is to provide a comprehensive database of Quaternary features that might generate strong ground motion and therefore, should be considered in assessing the seismic hazard throughout the country. In addition to printed versions of regional and individual state compilations, the database will be available on the World-Wide Web, where it will be readily available to everyone. The primary purpose of these compilations and the derivative database is to provide a comprehensive, uniform source of geological information that can by used to complement the other types of data that are used in seismic-hazard assessments. Within our CEUS study area, which encompasses more than 60 percent of the continuous U.S., we summarize the geological information on 69 features that are categorized into four classes (Class A, B, C, and D) based on what is known about the feature's Quaternary activity. The CEUS contains only 13 features of tectonic origin for which there is convincing evidence of Quaternary activity (Class A features). Of the remaining 56 features, 11 require further study in order to confidently define their potential as possible sources of earthquake-induced ground motion (Class B), whereas the remaining features either lack convincing geologic evidence of Quaternary tectonic faulting or have been studied carefully enough to determine that they do not pose a significant seismic hazard (Classes C and D). The correlation between historical seismicity and Quaternary faults and liquefaction features in the CEUS is generally poor, which probably reflects the long return times between successive movements on individual structures. Some Quaternary faults and liquefaction features are located in aseismic areas or where historical seismicity is sparse. These relations indicate that the record of historical seismicity does not identify all potential seismic sources in the CEUS. Furthermore, geological studies of some currently aseismic faults have shown that the faults have generated strong earthquakes in the geologically recent past. Thus, the combination of geological information and seismological data can provide better insight into potential earthquake sources and thereby, contribute to better, more comprehensive seismic-hazard assessments.

Open-File Report↗
USGS2014

Distribution and extent of heavy metal accumulation in Song Sparrows ( Melospiza melodia ), upper Santa Cruz River watershed, southern Arizona, 2011-12

Riparian ecosystems in arid environments provide critical habitat for breeding, migratory, and wintering birds, yet are often at risk of contamination by heavy metals. Birds and other animals living in contaminated areas are susceptible to adverse health effects as a result of long-term exposure and bioaccumulation of heavy metals. We investigated the distribution and cascading extent of heavy metal accumulation in Song Sparrows ( Melospiza melodia ) in Arizona’s upper Santa Cruz River watershed. This study had three goals: (1) quantify the degree of heavy metal accumulation in sparrows and determine the distributional patterns among study sites, (2) compare concentrations of metals found in this study to those found in studies performed prior to the 2009 international wastewater treatment plant upgrade, and (3) assess sparrow condition among sites with differing potential sources of contamination exposure. We examined six study sites that reflected different potential sources of contamination. Hematocrit values, body mass residuals, and leukocyte counts were used to assess sparrow condition. Cadmium, copper, mercury, nickel, and selenium exceeded background concentrations at some sites, but generally were lower than or similar to concentrations found in earlier studies performed prior to the 2009 international wastewater treatment plant upgrade. Concentrations were higher in recaptured birds in 2012 than in 2011 for 7 metals in feathers and 14 metals in blood, suggesting possible bioaccumulation. We found no cascading effects as a result of heavy metal exposure, but did find that heavy metal concentrations were reduced following the 2009 international wastewater treatment plant upgrade.

Arizona↗
USGS2014

Mapping habitat for multiple species in the Desert Southwest

Many utility scale renewable energy projects are currently proposed across the Mojave Ecoregion. Agencies that manage biological resources throughout this region need to understand the potential impacts of these renewable energy projects and their associated infrastructure (for example, transmission corridors, substations, access roads, etc.) on species movement, genetic exchange among populations, and species’ abilities to adapt to changing environmental conditions. Understanding these factors will help managers’ select appropriate project sites and possibly mitigate for anticipated effects of management activities. We used species distribution models to map habitat for 15 species across the Mojave Ecoregion to aid regional land-use management planning. Models were developed using a common 1 × 1 kilometer resolution with maximum entropy and generalized additive models. Occurrence data were compiled from multiple sources, including VertNet ( http://vertnet.org/ ), HerpNET ( http://www.herpnet.org ), and MaNIS ( http://manisnet.org ), as well as from internal U.S. Geological Survey databases and other biologists. Background data included 20 environmental covariates representing terrain, vegetation, and climate covariates. This report summarizes these environmental covariates and species distribution models used to predict habitat for the 15 species across the Mojave Ecoregion.

Mojave Ecoregion↗
USGS2017

Concentration and trend of 1,4-dioxane in wells sampled during 2002–2017 in the vicinity of the Tucson International Airport Area Superfund Site, Arizona

Industrial activities causing extensive groundwater contamination led to the listing of the Tucson International Airport Area (TIAA) as a Superfund Site in 1983. Early groundwater investigations identified volatile organic compounds (VOCs), including the chlorinated solvents trichloroethylene (TCE) and perchloroethylene (PCE), in wells in the area. Several responsible parties were identified and cleanup activities began in the late 1980s. In 2002, the compound 1,4-dioxane was discovered in wells in the area and has since been detected in measurable concentrations throughout the site. The U.S. Environmental Protection Agency (USEPA) classifies 1,4-dioxane as a likely human carcinogen. The purpose of this map is to present 1,4-dioxane concentrations in wells sampled from 2002 through mid-2017 in the TIAA Superfund Site area to indicate both the current status and trends in 1,4-dioxane groundwater contamination. This map includes data from wells in the commercial and residential community in the TIAA and does not include data from wells in suspected or confirmed source areas, such as Air Force Plant 44 and Tucson International Airport, or from wells within treatment facilities.

Arizona↗
USGS2000

Exploration

This summary of international nonfuel mineral exploration activities for 1999 draws upon available data from literature, industry and US Geological Survey (USGS) specialists. The report documents data on exploration budgets by region and commodity and identifies significant mineral discoveries and exploration target areas. It also discusses government programs affecting the mineral exploration industry. And it presents inferences and observations on mineral industry direction based on these data and discussions.

Mining Engineering↗
USGS2023

Community and citizen science on the Elwha River: Past, present, and future

This report reflects on the past, present, and potential future of community and citizen science (CCS) in the Elwha River watershed, with particular focus on the years before and after a major restoration event: the removal of two dams that had impacted the river system for a century. We ask: how does CCS feature in the Elwha story and how could it feature? We use the term CCS to reference the broad range of ways in which members of the public might participate in authentic science and monitoring processes, including students and both paid and unpaid interns: participants are individuals contributing to scientific projects without prior formal training in the topic. Removal of the Elwha dams was a large-scale, complex project, and communities had an important role to play: the Lower Elwha Klallam Tribe (LEKT) and other local groups were a large part of the original drive to remove the dams. Some funding and policy requirements for monitoring are ending, but there is still much to learn from the changes happening in the Elwha, requiring ongoing research and monitoring. In 2022, the Elwha scientific community came together in a multifaceted effort called the “Elwha ScienceScape” to mark the ten-year anniversary of dam removal and to plan for future monitoring. One of ScienceScape’s priorities is expanding CCS efforts, and because the Elwha dam removal is a powerful international symbol of large-scale watershed restoration, ScienceScape is well-positioned to inform and emphasize the potential role of CCS in dam removal worldwide. This report presents insights about Elwha CCS from an academic literature review and discussions with scientists and many others that have been working in the Elwha. We found that the history of CCS on the Elwha is important but understated, with few scientific papers acknowledging support by volunteers of various kinds. Recent and ongoing CCS projects on the Elwha tend to be focused on biological phenomena, and most are associated with educational opportunities (across many types of institutions) and paid internships. We also noted that most Elwha CCS projects required volunteers with particular pre-existing skill sets (e.g., botanical knowledge) or time to impart specialized training (e.g. boat use), leading many projects towards engagement with a smaller number of volunteers. Partners working in the Elwha are considering a wide range of potential new CCS projects, and these ideas are in varying stages of development. Many new projects would broaden public involvement in terms of the opportunities available and increase the variety of focal topics for research and monitoring. This increased breadth is promising: there are indications that the local community’s interests also range widely, from fish recovery after dam removal to dam removal impacts on humans. Elwha CCS projects have encountered some challenges and barriers, including the administrative burden of coordinating volunteers and managing liability concerns. But Elwha ScienceScape scientists are committed to the value that CCS brings both to the research itself as well as to those who participate in these projects. CCS can be a way to increase equity in science and engage people who would not otherwise participate in research, and in many cases the research simply wouldn’t be possible without their help. Support with project administration, volunteer management, and data management could help in expanding CCS efforts and broadening their inclusivity. More systematic tracking of CCS projects to assess how they contribute to research and to community and participant benefit could be helpful in establishing and maintaining a long-term CCS strategy in the Elwha.

Wshington↗
USGS2018

The Central African Republic Diamond Database—A geodatabase of archival diamond occurrences and areas of recent artisanal and small-scale diamond mining

The alluvial diamond deposits of the Central African Republic (CAR) are mined almost exclusively by way of informal artisanal and small-scale mining (ASM) methods. ASM sites range in diameter from a few meters to 30 meters or more, and are typically excavated by crews of diggers using hand tools, sieves, and jigs. CAR’s reported annual production has ranged from 300,000 to 470,000 carats over the past decade. This production is significant for CAR because it accounts for a large portion of the country’s export income and employs an estimated 60,000 to 90,000 miners nationally. Diamond production has also been linked to the violent conflict and political instability which have plagued the country for decades. The most recent conflict began in 2012 and resulted in an international embargo on the export of rough diamonds from CAR. This embargo was followed by a ceasefire and a return of peace in certain zones of the country in 2015; however, political and economic instability continues to afflict many areas of the country. International efforts to restore peace in CAR have included United Nations support as well as international technical assistance in tracking, assessing, and monitoring diamond production. In 2015, the Kimberley Process (KP) developed an operational framework allowing for legitimate exports from five subprefectures in CAR that were deemed to be compliant with KP internal controls and which were also considered to be free from systematic violence or control of armed groups. The goal of this study was to address information gaps regarding the location and extent of diamond occurrences and mining activity through the integration of geologic research with remote sensing, geographic information systems analysis, and fieldwork. Effective and efficient monitoring of diamond mining activity using satellite imagery requires detailed understanding of the geographic distribution of diamond sources and mining activities. A two-phase methodology was developed to address the knowledge gaps. The first phase consisted of the creation of a comprehensive geospatial catalogue of diamond mining and occurrence locations from archival records such as historical maps, mining reports, academic publications, and field data. Building upon this locational database, the second phase consisted of the creation of a geospatial dataset cataloguing current mining activity locations through manual interpretation of recently acquired satellite imagery. The accuracy of this second geospatial dataset was then assessed using field observations made between 2016 and 2017 by the U.S. Agency for International Development’s Property Rights and Artisanal Diamond Development II project. This report presents a two-part geodatabase: part 1 contains the locations of diamond mine sites and occurrences from archival sources, and part 2 indicates areas of current or recent mining activity. This geodatabase is unique in its temporal and spatial extent and may be used to analyze the geographic distribution of CAR’s known diamond resources, to assess the effect of recent violent conflicts and KP actions on diamond produc-tion, to provide decision makers with information regarding small-scale diamond mining, and to improve the monitoring of mining in regions of the country prone to conflict.

Open-File Report↗