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Mineral Resources of the McCullough Peaks Wilderness Study Area, Park County, Wyoming
From abstract: The McCullough Peaks Wilderness Study Area (WY-010-335) is located near the western edge of the Bighorn Basin, Park County, Wyoming. The area is about 10 miles northeast of Cody. Mineral and energy resource assessment of the McCullough Peaks Wilderness Study Area indicates a total of 52 million tons of measured and indicated subbituminous coal resources.
Mineral Resources of the Negro Bill Canyon Wilderness Study Area, Grand County, Utah
Abstract: The Negro Bill Canyon (UT-060-138) Wilderness Study Area is in southeastern Utah in Grand County southeast of Arches National Monument and covers 7,620 acres. No mineral resources are identified in the study area. Lode mining claims cover the western part of the Negro Bill Canyon Wilderness Study Area; there are no patented claims in the study area. The mineral resource potential for gypsum, potash, halite, and bentonite on the surface and in the subsurface beneath the wilderness study area is high. The energy and mineral resource potential for oil, gas, carbon dioxide, uranium and vanadium on the surface and beneath the wilderness study area is moderate. The potential for helium gas, geothermal sources, and metals other than uranium and vanadium is low.
Mineral Resources of the Sleeping Giant Wilderness Study Area, Lewis and Clark County, Montana
From abstract: A mineral resource survey was conducted in 1987 by the U.S. Geological Survey and the U.S. Bureau of Mines to evaluate mineral resources (known) and mineral resource potential (undiscovered) of the Sleeping Giant Wilderness Study Area (MT-075-111) in Lewis and Clark County, Montana. The only economic resource in the study area is an inferred 1.35-million-ton reserve of decorative stone (slate); a small gold placer resource is subeconomic. A high resource potential for decorative slate exists directly adjacent to the area of identified slate resource and in the northeastern part of the study area. The rest of the study area has a low potential for decorative slate. The westernmost part of the study area has a moderate resource potential for copper and associated silver in strata-bound deposits in green beds and limestone; potential is low in the rest of the study area.
Mineral Resources of the Willow Creek and Skull Creek Wilderness Study Areas, Moffat County, Colorado
Abstract: The Willow Creek Wilderness Study Area (CO-010-002) and the Skull Creek Wilderness Study Area (C-010-003), which contain 13,368 acres and 13,739 acres, respectively, are in northwest Colorado near the Utah border. There are no identified resources in either of the study areas. The study areas have low resource potential for undiscovered uranium, vanadium, copper, and all other metals; oil and gas; and coal.
Mineral Resources of the Coal Canyon, Spruce Canyon, and Flume Canyon Wilderness Study Areas, Grand County, Utah
From abstract: The Coal Canyon (UT-060-1000), Spruce Canyon (UT-060-100D), and Flume Canyon (UT-060-100B) Wilderness Study Areas are in the Book Cliffs in Grand County, eastern Utah. Demonstrated coal reserves totaling 22,060,800 short tons, and demonstrated subeconomic coal resources totaling 39,180,000 short tons are in the Coal Canyon Wilderness Study Area. Also, inferred subeconomic coal resources totaling 143,954,000 short tons are within the Coal Canyon Wilderness Study Area. No known deposits of industrial minerals are in any of the wilderness study areas. All three of the wilderness study areas have a high resource potential for undiscovered deposits of coal and for undiscovered oil and gas.
Mineral Resources of the Paria-Hackberry Wilderness Study Area, Kane County, Utah
From abstract: The Paria-Hackberry Wilderness Study Area, in central Kane County, southern Utah, is a region of generally flat-lying, gently folded sedimentary rocks, bounded on the east by the east-dipping limb of the East Kaibab monocline and cut by sheer-walled, narrow canyons. The area selected for study by the U.S. Bureau of Land Management totaled 94,642 acres (148 square miles); because of uncertainty as to final boundaries, the U.S. Geological Survey studied an additional contiguous 41,180 acres (64 square miles).
Mineral Resources of the Wabayuma Peak Wilderness Study Area, Mohave County, Arizona
From abstract: The Wabayuma Peak Wilderness Study Area (AZ-020-037/043), for which a mineral survey was requested by the U.S. Bureau of Land Management, encompasses 40,118 acres in northwestern Arizona. Fieldwork was carried out in 1986-88 by the U.S. Bureau of Mines and the U.S. Geological Survey to appraise the identified (known) resources and assess the mineral resource potential (undiscovered) of the wilderness study area. Within the Wabayuma Peak Wilderness Study Area are 14 private parcels of land totaling 1,315 acres. The Wabayuma Peak Wilderness Study Area, including the 14 private parcels of land, is herein referred to as the "wilderness study area" or the "study area." The Boriana, Antler, and Copper World mines lie near the east boundary of the study area. The Boriana mine was a major tungsten-producing mine of the United States during World War II. The Antler and Copper World mines produced relatively small amounts of copper and zinc prior to 1970.
Mineral Resources of the Warm Springs Wilderness Study Area, Mohave County, Arizona
From abstract: At the request of the U.S. Bureau of Land Management, approximately 113,500 acres of the Warm Springs Wilderness Study Area (AZ-020-028/029) were evaluated for mineral resources and mineral resource potential. In this report, the area studied is referred to as the "wilderness study area" or "study area"; any reference to the Warm Springs Wilderness Study Area refers only to that part of the wilderness study area for which a mineral survey was requested. This study area is located in west-central Arizona. The U.S. Geological Survey and the U.S. Bureau of Mines conducted geological, geochemical, and geophysical surveys to appraise the identified mineral resources (known) and assess the mineral resource potential (undiscovered) of the study area. Fieldwork for this report was carried out largely in 1986-1989.
Mineral Resources of the Black Mountains North and Burns Spring Wilderness Study Areas, Mohave County, Arizona
From abstract: At the request of the U.S. Bureau of Land Management, approximately 19,300 acres of the Black Mountains North Wilderness Study Area (AZ-020-009) and 23,310 acres of the Burns Spring Wilderness Study Area (AZ-020-010) were evaluated for mineral resources and mineral resource potential. In this report, the area studied is referred to, collectively or individually, as the 'wilderness study area' or simply 'the study area'; any reference to the Black Mountains North or Burns Spring Wilderness Study Areas refers only to that part of the wilderness study area for which a mineral survey was requested by the U.S. Bureau of Land Management. The study area is located in western Arizona, about 30 mi northwest of Kingman. There are no identified resources in the study area.
Mineral Resources of the Desolation Canyon, Turtle Canyon, and Floy Canyon Wilderness Study Areas, Carbon, Emery, and Grand Counties, Utah
From abstract: In 1985, 1986, and 1988, the U.S. Bureau of Mines and the U.S. Geological Survey studied the Desolation Canyon (UT-060-068A), Turtle Canyon (UT-060-067), and Floy Canyon (UT-060-068B) Wilderness Study Areas, which are contiguous and located in Carbon, Emery, and Grand Counties in eastern Utah. The study areas include 242,000 acres, 33,690 acres, and 23,140 acres respectively. Coal deposits underlie the Desolation Canyon, Turtle Canyon, and Floy Canyon study areas.
Characterization of Chronic Sources and Impacts of Tar along the Louisiana Coast
No Description Available.
Gulf of Mexico Offshore Operations Monitoring Experiment
An interim report of the "Gulf of Mexico Offshore Monitoring Experiment (GOOMEX): Phase 1" that analyzes the effects of offshore drilling and its resultant contaminants on the life cycles and composition of resident marine life. Data obtained from soil and tissue samples of marine life both near and far from contaminated areas is used to determine and manage the environmental changes rendered by offshore drilling.
Our Changing Planet: The FY 1999 U.S. Global Change Research Program
The purpose of this report, which was prepared under the auspices of the President's National Science and Technology Council (NSTC), is to provide highlights of the Program's recent research and to describe future plans and directions.
Methane Emissions from the Natural Gas Industry: Volume 2: Technical Report
This report describes the results of a study to quantify the annual methane emissions from the natural gas industry.
Methane Emissions from the Natural Gas Industry, Volume 1
This study is documented in a multi-volume set where this executive summary is the first volume. It is major sstudy to quantify methane emissions from U.S. natural gas operations.
News-Notes, Number 19, March 1992
Bulletin providing information and news about the condition of the water-related environment, the control of nonpoint sources of water pollution (NPS), and the ecosystem-driven management and restoration of watersheds in the United States.
Wetlands Losses in the United States 1780's to 1980's
Report to Congress on the status of wetland resources in the United States. This report, a one-time effort, focuses on documenting historical wetland losses that occurred from colonial times through the 1980s.
Form CJ-8, Probation Data Survey: 1999
Blank probation data survey containing a series of questions related to the probationary population in a particular location, with instructions for filling out the survey.
Revisions to the Unregulated Containment Monitoring Regulation for Public Water Systems
64 FR 50556. Final rule establishing criteria for a program to monitor unregulated contaminants and to publish a list of contaminants to be monitored under the Safe Drinking Water Act (SWDA), as amended in 1996.
Form CJ-7, Parole Data Survey: 1999
Blank parole data survey containing a series of questions related to the parole population in a particular location, with instructions for filling out the survey.
Texas Costal Wetlands: Status and Trends, Mid-1950s to Early 1990s
This report analyzes data collected for the 12.8 million-acre coastal Texas area to detect changes in wetlands, deepwater habitats, and uplands acreage.
Final Administrative Changes to the Coastal Nonpoint Pollution Control Program Guidance for Section 6217 of the Coastal Zone Act Reauthorization Amendments of 1990 (CZARA)
Final revisions by the National Oceanic and Atmospheric Administration (NOAA) and the Environmental Protection Agency (EPA) regarding guidelines for coastal states to develop programs to reduce polluted runoff in accordance with the Coastal Zone Act Reauthorization Amendments of 1990 (CZARA). The text outlines administrative changes to the program including targeting, enforceable policies and mechanisms, timeframes, program implementation/evaluation, and resources. It also includes the transmittal letter, outlining the purpose.
Structural Analysis of a Mechanized LHD Trench Undercut Caving System
Abstract: This U. S. Bureau of Mines (USBM) report presents results of stress analyses and field observations to investigate the effects of elevated trench drifts on the structural stability of rock mass zones surrounding a production draw drift in a mine utilizing a mechanized load-haul-dump (LHD) trench undercut panel caving system. A two-dimensional boundary-element mine stress model was developed to predict the locations and extent of damaged rock mass zones surrounding draw drifts where adjacent, parallel trench drifts are either elevated or not elevated above the LHD production draw drift level. A Mohr-Coulomb shear-failure criterion was obtained directly from in situ borehole shear test data. Hoek-Brown shear-failure parameter values were computed from borehole-shear and triaxial test data. A procedure is described to estimate these parameters when a rock mass rating (RMR) value and triaxial data on intact samples exist, and no borehole shear test data exist. Results indicate that trench drifts, elevated to the level equal to the height of the LHD production draw drift, would not minimize material damage nor significantly enhance the stability of rib and crown pillar zones surrounding production draw drifts in the mechanized LHD trench undercut caving panel investigated at this mine.
Effects of Remote Drop and Pumpdown Placement on Cellular Concrete
Abstract: The hazards to the public posed by abandoned mine shafts are well documented. As private development encroaches on previously mined areas, the potential for fatalities and serious injuries from abandoned mine shafts increases. The U.S. Bureau of Mines has conducted research into cellular concrete as a material for sealing these openings. The current work involves testing the characteristics of cellular concrete before and after it had been pumped or dropped from different heights into a simulated mine shaft. Cellular concrete was pumped vertically up to and subsequently dropped from heights of 18 and 37 m into concrete forms. Wet density measurements were made at multiple sampling points in the test circuit. Air content determinations and uniaxial compressive strength testing were conducted. Research results showed significant loss in air content and changes in the characteristics of cellular concrete during pumping or dropping from various heights. Recommendations on effective use of cellular concrete for sealing abandoned mine shafts are made.
Improved Performance of Linear Coal Cutting Compared with Rotary Cutting
From abstract: The linear cutting system, developed by the U.S. Bureau of Mines, uses geometric principles developed by Cardan to produce a nearly constant cut depth. The new system has been extensively tested in a synthetic material under laboratory conditions to verify mechanical capability and to identify operational characteristics. This report details the improved performance versus rotary cutting.
Ten-Cycle Bench-Scale Study of Simplified Clay-Hydrogen Chloride Process for Alumina Production
From abstract: This U.S. Bureau of Mines (USBM) research simplified an earlier hydrogen chloride (HCl) leachsparge process developed by the USBM to recover reduction-grade alumina from domestic kaolin clay. Improvements were made by decreasing the initial leaching acid concentration from 25 to 20 pct, decreasing the leaching time from 1 to 2 h to 15 to 30 min, eliminating the solvent extraction step for Fe removal, and eliminating the step to recover the Al content of the bleedstream circuit. A 10-cycle bench-scale experiment of the simplified process showed that the ferric chloride (FeC 3) concentration built up to 9.3 g/L in the recycle stream. This did not interfere with any of the unit operations or final alumina product purity because Fe forms stable soluble chloride complexes when sparged with HC and is easily washed from the large aluminum chloride hexahydrate (ACH) crystals. The reduced leaching time and acid concentration did not decrease Al extraction.
High-Temperature Cyanide Leaching of Platinum-Group Metals from Automobile Catalysts--Pilot Plant Study
From abstract: The U.S. Bureau of Mines Reno Research Center investigated, developed, and patented a high temperature cyanide leaching process for recovering platinum-group metals (PGM) from automobile catalysts. A batch pilot plant was constructed at the center and operated to demonstrate this technology to industry.
Teleoperation of a Compact Loader-Trammer
Abstract: The U.S. Bureau of Mines has developed a portable, inexpensive teleoperation system for mobile hard-rock mining equipment. The system was tested on a compact loader-trammer in a simulated stope. The teleoperation system includes radio remote control and computer-assisted navigation. A recent enhancement includes video cameras mounted on the machine to provide visual information to the operator. This system allows the operator to remain in a safe location while operating the machine from a distance, thus increasing both operator safety and mining productivity.
Field Demonstration of Two Pneumatic Backfilling Technologies
Abstract: This U.S. Bureau of Mines (USBM) report summarizes a field demonstration of pneumatic backfiling technologies conducted at the abandoned Hillside Coal and Iron Slope in Vandling, PA. Researchers demonstrated tro pneumatic backfilling technologies recently developed under the USBM's Abandoned Mine Reclamation Research Program, the Pneumatic Pipefeeder and the High-Efficiency Ejector. Both systems had previously been evaluated at the USBM's subsidence abatement investigation laboratory near Fairchance, PA. The objective of the demonstration was to fill 100% of the abandoned tunnel with backfill stone to prevent further subsidence. The Pneumatic Pipefeeder was used for 21 days, at a rate of 63 to 124 t/d (69 to 136 st/d), to fill 88% of the tunnel. The High-Efficiency Ejector was used for 2 days, at a rate of 125 to 132 t/d (138 to 146 st/d) to fill the remaining 12% of the tunnel. The backfill placed by both systems was tightly compacted. The major problem encountered was wear on the polyethylene pipeline from the abrasion of the high-velocity backfill. The use of heavier steel pipe minimized the problem. A cost analysis for the entire project is given.
Development of Coal Combustion Sensitivity Tests for Smoke Detectors
Standard smoldering and flaming combustion tests using small coal samples have been developed by the U.S. Bureau of Mines as a method to evaluate the response of a smoke detector. The tests are conducted using a standard smoke box designed and constructed according to Underwriters Laboratories. The tests provide a standard, easily reproducible smoke characteristic for smoldering and flaming coal combustion, based upon a comparison of the smoke optical density and the response of a standard ionization chamber to the smoke. With these standard tests, the range of threshold limits for the response of a smoke detector and the detector's reliability can be evaluated for nearly identical smoke visibility and smoke physical characteristics. The detector's threshold response limits and reliability need to be well defined prior to the instrument's use as part of a mine fire warning system for improved mine safety.
Reactivity in the South Spoils and Hillside Dump at the Midnite Mine
The Midnite Mine is an inactive open-pit uranium mine located on the Spokane Indian Reservation in Washington State. Drill samples from two large waste rock dumps on the site, known as South Spoils and Hillside Dump, were collected with a Becker hammer drill and evaluated to determine potential of the rock to generate acid mine drainage (AMD). Waste rock at this mine contains both pyrite and uranium, and AMD effects are more complicated on this site than most in that uranium is soluble in both acidic and neutral aqueous solutions. Although AMD protocols identified 26% of the South Spoils samples as potentially acid, under 7% of the spoil samples were actually producing acid. Considerable calcite exists in the South Spoils, and weathering feldspars further contribute to acid neutralization. The Hillside Dump has low concentrations of pyrite and calcite that acid-base accounting protocols would predict to be non-acidic. Accumulation of sulfate in rocks with concentrations of less than 0.3% S causes some of those normally non-acid producing rocks to produce acid in the Hillside Dump.
Data Dictionary and Discussion for the Midnite Mine GIS Database
Abstract: A geographic information system (GIS) database has been developed by the U.S. Bureau of Mines (USBM) for the Midnite Mine and surroundings in northeastern Washington State (Stevens County) on the Spokane Indian Reservation. The mine is an open pit uranium mine which has been inactive since 1981. The GIS database was compiled to serve as a repository and source of historical and research information on the mine site. The database supported USBM hydrological and reclamation research on the mine site. The database also will be used by the Bureau of Land Management and the Bureau of Indian Affairs (as well as others) for environmental assessment and reclamation planning for future remediation and reclamation of the site. This report describes the data in the GIS database and their characteristics. The report also discusses known backgrounds on the data sets and any special considerations encountered by the USBM in developing the database. Most of the database also is planned to be available to the public as a two-CD-ROM set, although separately from this report.
Inflatable Devices for Use in Combating Mine Fires
Abstract: The U.S. Bureau of Mines is conducting full-scale laboratory studies on the development of lightweight inflatable devices that can be used for rapidly isolating mine fire areas to allow for fire suppression and/or personnel escape. These inflatable devices were able to stop airflows of over 1,100 m3/min within several minutes. The remotely installed bag was designed to rapidly isolate the fire zone and to then serve, if necessary, as a containment form for the remote injection of low-dersil organic or inorganic foams. Other inflatable bag concepts that were tested include an inflatable feed-tube seal for high-expansion foam generators and a positive pressure inflatable walk-through escape device. Laboratory studies indicated that a high-expansion foam plug will travel 183 m through an entry with a 4.5 pct rise in elevation before foam leakage from around the inflatable feed-tube seal. Additionally, the positive-pressure, inflatable walk-through escape device with its "pass-through" feature may allow extra time for personnel evacuation. All of these inflatable devices have shown merit during laboratory studies in providing a rapid method for isolation of a mine fire prior to suppressant foam injection or personnel escape.
Real-Time Monitoring of Field Measurements for Mine Design: Greens Creek Mine, Admiralty Island, Alaska
Abstract: Researchers at the U.S. Bureau of Mines conducted field investigations at the Greens Creek Mine in southeast Alaska for the purpose of validating computer design of mining methods and assessing real-time monitoring capabilities. The field study required the application of new technology because of the remoteness of the study site, the need for timely acquisition of data, and a limited budget for instruments and data acquisition. Various sensors were installed to monitor rock mass deformation and strain, temperature, SO gas emissions, and blasting. Data were collected through a distributed personal computer network and high-speed modems. These readings were used to develop visualization models of underground metal mining operations and drift-and-fill mining and real-time graphics displays of ground conditions. Results of the field tests showed that it is possible to gather, process, visualize, and verify mine designs on a real-time basis.
1995 Midnite Mine Radiation Survey
Abstract: During the week of September 4, 1995, personnel from the U.S. Bureau of Mines conducted a Ra-226 survey at the Midnite Mine. One hundred thirty measurements were made on a rectangular grid with 150-m spacings. Concurrently, Shepherd Miller, Inc., took gross gamma readings in gR/h at the same grid points. In addition, the USBM collected 17 soil samples to be analyzed for radium, thorium, and potassium. The results of this survey are summarized in this report.
Groundwater Flow Model (GWFM) Development, Midnite Mine, Wellpinit, Washington
This Report of Investigations (RI) is one of several describing work that has been completed by the U.S. Bureau of Mines at the Midnite uranium mine, Wellpinit, WA. Dean (in preparation) describes the entire project history. Four diskettes containing three archives compressed using WINZIP (or PKZIP) accompany the current RI. The ultimate purpose of this research effort was to develop a groundwater flow model (GWFM) for the Midnite Mine that can be utilized by the contractor preparing the Environmental Impact Statement (EIS) and by other interested parties. The objectives of this study were to (1) develop a shell model of the geology at the site, (2) develop the basis for a GWFM that will meet criteria described elsewhere in this RI and that can be updated with new information generated during the EIS process, and (3) present the results of two steady-state simulations of groundwater flow within the bedrock units. The current GWFM generates nonunique solutions because flow data for the bedrock units currently do not exist. However, the model provides useful results with respect to direction of flow. More data are required to model the bedrock aquifer system accurately. Volmnetric flow rates of the bedrock units should be measured or estimated. Measurements obtained from one or two drains completed in the bedrock in the southern portion of the site should yield these values.
U.S. Bureau of Mines Final Report : Midnite Mine Water Treatment Studies
The U.S. Bureau of Mines reviewed and evaluated options for treatment of the approximately 500 million gallons of contaminated water in flooded pits at the Midnite Mine on the Spokane Indian Reservation. While current lime treatment produces discharge quality water, the resultant sludges are radioactive, presenting a disposal problem. Of the 24 commercial processes and seven emerging technologies evaluated, none demonstrated a significant advantage over ion exchange using a strong base anion exchange resin in either laboratory or field tests. Uranium was lowered from 22 ppm to 0.2 ppb in treated water. Radium was lowered from 44 pCi/L to <1 pCi/L using a modified precipitation with BaCl2 . The natural zeolite, clinoptilolite, lowered radium to 6-8 pCi/L when used as an ion exchanger.
Hydraulic Characterization of Midnite Mine, Wellpinit, Washington: Summary of 1994 Field Season
The Midnite Mine is an inactive uranium mine on the Spokane Indian Reservation in Washington State. Oxidation of sulfide-containing minerals, primarily pyrite, produces acidic water. Uranium and other radioactive constituents are chemically leached and dissolved in ground and surface waters. The U.S. Bureau of Mines (USBM) has worked closely with the Bureau of Indian Affairs, the Bureau of Land Management, and the Spokane Tribe of Indians to address data needs for remediation of the disturbed area. As part of this effort, USBM personnel initiated research to determine water quality and define groundwater flow characteristics. Preliminary results of hydraulic stress tests performed in the bedrock at the site are described. Slug tests and pumping tests were conducted using preexisting USBM monitoring wells. Slug test results were used to generate hydraulic conductivity estimates for fractured and unfractured intrusives. The pumping tests demonstrated varying degrees of spatial continuity. Hydraulically continuous fractured zones along north-south planes were demonstrated in two cases for distances of 90 and 116 m (300 and 380 ft). The short-term pumping tests provided no evidence of east-west hydraulic continuity in fractured zones.
Midnite Mine Summary Report
The Midni'e Mine is an inactive, hard-rock uranium mine in Stevens County, WA. Oxidation of sulfide-containing minerals in the ore body produces large quantities of acidic water. The U.S. Bureau of Mines was directed by Congress in Fiscal Year 1994 to perform technological research on the treatment of radioactive water and disposal of treatment residues at the Midnite Mine and en overall site reclamation. This Report of Investigations summarizes the studies that were completed on: 1) treatment alternatives for uranium contaminated acid mine drainage, and 2) overall site reclamation, including: ground water flowpaths in the bedrock, radiation, and waste rock reactivity. As an aid to site reclamation, a Geographic Information System database was also produced that contains available current and historic data and information on the Midnite Mine. This report explains the scope of the Bureau's study and summarizes the results of its investigations.
Dust Sources and Controls for Multiple-Machine Longwall Faces
Abstract: Longwall mining in lower seam heights may necessitate the use of single-drum shearers to overcome size constraints associated with standard double-drum shearers. To avoid the operational problem of clearance in the tailgate entry with one single-drum shearer, two single-drum machines can be operated on the same face, with each shearer responsible for mining a predefined portion of the face. However, utilization of two shearers on the same face necessitates the positioning of one shearer operator and a jacksetter in the return air of the upwind shearer, thus complicating respirable dust control on the longwall. In an effort to evaluate the unique dust control problems associated with this type of mining, the U.S. Bureau of Mines conducted dust surveys on two multiple-machine longwall operations. Sampling was done to quantify major sources of respirable dust and to identify potential solutions to problem areas. Sampling results indicate that the cutting sequences utilized on multiple-machine faces may have to be designed to minimize dust exposure, as opposed to optimizing productivity or facilitating operational requirements. Also, state-of-the-art dust control techniques typically found on double-drum shearer longwalls must be employed to help minimize the exposure of all face personnel to traditional dust sources.
Petrographic and Geochemical Analyses of Leach Samples from Artillery Peak, Mohave County, Arizona
Abstract: The first step in determining whether Mn can be recovered by in situ leaching is to develop and test a selective lixiviant. Two column leach tests and one core leach test were conducted by the U.S. Bureau of Mines on Mn oxide ore using aqueous sulfur dioxide (SO2) as the lixiviant. The column tests showed that aqueous SO2 could selectively dissolve available Mn oxides from calcite-rich ore in a heap leach system. However, the core test showed that calcite gangue side reactions can have pronounced negative effects on the likelihood of successful in situ leaching of a calcite-rich ore with aqueous SO2. Petrographic and geochemical analyses showed that both Mn (IV, II) oxides and calcite were dissolved. The abundance of dissolved Ca caused precipitation of gypsum. Acid consumption by calcite dissolution caused a rise in pH that caused the S02/S species to shift to SO32- (sulfite), which hindered reductive dissolution of Mn oxide. Gypsum precipitation did not affect complete leaching of the rock fragments in the column tests; however, it plugged the natural permeability in the core. Manganese recoveries were high for the column tests and low for the core test.
Improved Grindability of Taconite Ores by Microwave Heating
The 11.S. Bureau of Mines has conducted studies to utilize rapid microwave heating to stress fracture ore samples. Iron ores containing hematite, magnetite, and goethite were subjected to microwave energy in batch operations at 3 kW and heated to average maximum temperatures between 840 and 940 *C. Standard Bond grindability tests showed that microwave heating reduced the work index of iron ores by 10 to 24 pct. In a microwave chamber designed to simulate a continuous throughput operation at 3 kW, the grindability of a tacon-te ore was improved by 13 pct at a bulk temperature of 197 *C. Because stress cracking occurred at a lower temperature, less energy was consumed. To further improve the economics of microwave fracturing, higher powers up to 16 kW were used to rapidly heat samples to relatively low temperatures in a continuous, belt-fed applicator. A significant improvement of grindability was obtained with a larger rod mill feed size in comparison to a minus 6-mesh Bond feed.
Numerical Modeling Analysis of Stress Transfer Modification Concepts for Deep Longwall Mines
Abstract: This U. S. Bureau of Mines (USBM) report evaluates three stress-transfermodification concepts for their potential in reducing longwall gate road stresses and closures. In each of the three concepts - packwalling, gob infilling, and entry filling - support structures are constructed on the headgate side of the panel parallel with or inby the face line. When the headgate becomes the tailgate of the adjacent panel, these structures are in place to accept stresses transferred from the mined-out panel. Using the USBM nonlinear boundary-element program MULSIM/NL, baseline models of typical longwall stress transfer behavior were developed for both intermediate depth and deep mining conditions. These models were verified by comparing model results with field measurements and observations. The stresstransfer-modification concepts were then incorporated into the deep baseline model to quantify the effects of each concept on tailgate closure. Modeling results indicated that entry filling is the most effective concept in reducing tailgate escapeway closure. Using only 18 m3 of a weak fill per meter of face advance (7.3 yd3 per ft of face advance), tailgate escapeway closure was reduced by 33%. By improving the quality of the fill, similar results were achieved using 50% less volume.
Well-Point Containment of Impoundment Leakage
Research was conducted to evaluate the effectiveness of a well-point dewatering system in conjunction with a french drain to intercept waste impoundment leakage while reducing the volume of waste water requiring treatment. A well-point dewatering system composed of 585 production wells was installed around the perimeter of a leaking impoundment that previously used only a french-drain system for leakage control. The placement of the well-point system was designed to intercept and remove the leakage from the groundwater before the contaminant reached the french drain. Groundwater monitoring at this site revealed that after a period of approximately 40 days the well-point dewatering system had stabilized and effectively prevented the further spread of contamination to the french drain.
Bending Fatigue Tests on Flattened Strand Wire Rope at High Working Loads
Abstract: The U.S. Bureau of Mines established a wire rope research laboratory to examine the factors that affect the safety and the useful life of wire rope. In the most recent work, two 32-mm 6x27H flattened strand ropes were degraded on a bending fatigue machine. The two tests were run at constant loads of 285 and 347 kN or safety factors of 2.5 and 2. Nondestructive and tensile strength tests were performed on samples of the ropes to determine the relationship between rope deterioration and rope breaking strength. Neither the area loss nor the number of broken wires measured from nondestructive tests could be used as clear indicators of the loss of strength. However, it was found from the tensile tests for both rope specimens that the strength loss was associated with the reduction of breaking strain. This suggests that measuring the strain of many short sections of a rope in the elastic region may locate the high stress sections and thus determine the condition of the rope.
Human Factors Analysis of Roof Bolting Hazards in Underground Coal Mines
Abstract: The U.S. Bureau of Mines conducted a human factors analysis of hazards associated with roof bolting activities in underground coal mines. Emphasis was placed on hazards related to the movement of the drill-head boom or mast of a roof bolting machine. The objective was to identify hazards and recommend solutions. The data-collection effort consisted of analysis of U.S. Mine Safety and Health Administration accident data; visits to underground mines and interviews with experienced roof bolting machine operators; discussions with roof bolting machine manufacturers; interviews with workers injured while performing roof bolting tasks; and reviews of research on roof bolting safety. A set of recommendations to increase the safety of roof bolting operations was developed. In particular, the following list of recommendations was presented in ranking order: (1) use an interlock device to cut off power to controls when an operator is out of position,,(2) place fixed barriers at pinch points, (3) provide appropriate control guarding, (4) reduce fast-feed speed, (5) use automatic cutoff switches at pinch points, (6) redesign control bank to conform to accepted ergonomic principles, and (7) use resin insertion tools and resin cartridge retainers.
Electrochemical Reduction of Titanium in Nonaqueous Solvents
Abstract: Electrorefining of Ti in nonaqueous solvents has been studied by the U.S. Bureau of Mines as a method for recycling impure scrap Ti. Electrochemical behavior of Ti species was investigated using cyclic voltammetry. Research results showed that Ti metal can be dissolved in polar solvents such as dimethylformamide or dimethyl sulfoxide. However, deposition of Ti from these solvents was not successful. Several solvent systems were investigated for electrodepos.tion of Ti but no deposits were obtained. Reduction of Ti' complexes to Ti" proved to be straightforward, but reduction to lower oxidation states could not be confirmed. In dimethylformamide solutions, cyclic voltammetry results demonstrated the reduction of Ti to an oxidation state of less than three, but no Ti metal was identified. In dimethyl sulfoxide solutions containing LiCl, it was possible to deposit Li metal. After adding Ti salts to the solution, electrolysis quickly passivated the electrode. Deposition of Ti was also investigated in solutions of dimethoxyethane and propylene carbonate but, again, no reduction of Ti to oxidation states of less than three occurred. Therefore, the prospects for a nonaqueous electrorefining system for Ti metal do not appear promising.
The Reduction of Airborne Dust Generated by Roof Bolt Drill Bits Through the Use of Water
Abstract: In the vast majority of American coal mines, roof bolt holes are drilled dry, mainly because of mine operator concern with the spent water creating adverse working conditions. Wet drilling, however, can increase drilling rates and the effective lifetime of the drill bits used. This study, carried out as part of an ongoing cooperative research program between the U.S. Bureau of Mines and the University of Missouri-Rolla, shows that the large volumes of water conventionally used in wet drilling are not necessary, and the performance benefits from wet drilling can be achieved with total volume flows on the order of 0.4 L per hole. This conclusion is validated based on the measured respirable dust generated in drilling Berea sandstone. The results are confirmed using a variety of bit shapes, which are also shown to have a significant effect on penetration rate.
Timing and Duration of Subsidence Due to Longwall Mining
Subsidence data gathered by the U.S. Bureau of Mines over a series of longwall panels in the Pittsburgh Coalbed were studied to obtain insight as to the role of time in the subsidence process. It was found that subsidence began essentially with undermining and was completed within 1 year. The progress of the subsidence was dependent upon location above the panel. Subsidence in the central area of the subsidence trough, where subsidence is the greatest, was about 90 pct complete by the time the face had progressed a distance equal to one overburden thickness beyond a particular surface point. For a point over the rib of the longwall panel, the subsidence was only about 60 pct complete at this time. Data from three other sites in the northern Appalachian Coal Basin were analyzed to determine if an anomaly or the true characteristics of the subsidence process had been observed. All sites behaved similarly in the central portion of the subsidence trough. However, the subsidence of points over and adjacent to the ribs of the longwall panels was site specific. The fact that movement across the width of the panel was not uniform should be taken into account in assessing damages or the potential for damages resulting from mining-induced subsidence.
An Adaptive System for Process Control
Abstract: Researchers at the U.S. Bureau of Mines (USBM) have developed adaptive process control systems in which genetic algorithms (GA's) are used to augment fuzzy logic controllers (FLC's). GA's are search algorithms that rapidly locate near-optimum solutions to a wide spectrum of problems by loosely modeling the search procedures of natural genetics. FLC's are rule-based systems that efficiently manipulate a problem environment by modeling the "rule-of-thumb" strategy used in human decisionmaking. Together, GA's and FLC's include all of the capabilities necessary to produce powerful, efficient, and robust adaptive control systems. To perform efficiently, such control systems require a cont element to manipulate the problem environment, an analysis element to recognize changes in the problem environment, and an adaptive element to adjust to the changes in the problem environment. The control system also employs a computer simulation of the problem environment. Details of an overall adaptive control system are discussed. A specific laboratory acid-base pH system is used to demonstrate the ideas presented; all results are from the physical laboratory system and not from a computer simulation.