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By Robert T. Beckman

Education of inspection and operating personnel is essential to protection from radiation hazards in the mining industry. For over 10 years, MSHA has presented the only formal course on radiation measurements and control available to the mining community. Course objectives and content are described in this paper.

Jan 1, 1981

By J. R. Nawrot

Reclamation of potentially acid producing coal processing waste requires a 4-foot cover, and/or treatment to allow vegetation establishment. If not planned properly, soil covering alone does not prevent refuse acidification or formation of acid seeps. Adequate neutralization enhancement prior to soil covering can maintain an alkaline environment in the soil refuse interface and prevent acidification. Direct vegetation establishment using only limestone amendment (without soil cover) can successfully reclaim aged and weathered fine (Blurry) and coarse (gob) refuse if adequate neutralization treatment is provided for the oxidized surface zone. Acid seeps, representing an "after-the-fact" verification of an imbalance of acid-base equilibrium may also be corrected using upslope alkaline recharge techniques. Concentrated alkaline recharge pools have been constructed above previously soil covered acid gob at the Peabody Will Scarlet Mine to abate acid seeps. Preliminary monitoring results (1989-1992) from a concentrated alkaline recharge pool demonstration project in the Pit 4 area of the Will Scarlet Mine have documented a 50 to 80 percent reduction in acidity in the principal recharge pool groundwater zone. A 22% reduction in acidity has occurred in the primary seeps located downslope from the alkaline recharge pools. The initial improvements in water quality are seen as a positive indication that groundwater acidity will decrease further and amelioration of the acid seep will continue.

Jan 1, 1993

By P. S. Newall

As part of a much larger research project, factor analysis was employed to help interpret and compare the geochemical signatures produced by two different sample media; a traditional -80# soil fraction, and a coarse float. Both sample types were collected by hand auger from the extension zone of the Redmoor sheeted-vein complex and analyzed -for 19 major and trace elements. The rationale behind the study infers that the geochemical anomalies produced by wallrock alteration around such targets can be better detected in the lithogeochemical rather than the soil environment, sometimes at considerable distance from their source.

Jan 1, 1991

By Bert C. Morrison

In 1961. American Smelting and Refining Company was conducting exploration for lead in southeastern Missouri using several geophysical methods. Electrical methods were used in almost every hole drilled during this period. These methods met with only limited success, with one exception. This paper deals with that exception: An Electrical Potential Method used at a single hole to indicate direction to better mineralization. This method was notably successful in the program.

Jan 1, 1970

By Stan Tang, Yiming Sun, S. Amir Reza Beyabanaki, N. Sathi Sathialingam

The Kurve mixed-use development project including a 22-story tower at 2801 Sunset Place was constructed on a site consisting of a roughly rectangular-shaped lot at the intersection of Wilshire Boulevard and Hoover Street in Los Angeles. Two Metro Red Line tunnels, with depths of approximately 30 feet and 58 feet, respectively, cross below the building at distances of approximately 1 foot to over 63 feet from the site. This paper presents numerical modeling performed to evaluate the ground and tunnel behavior in response to building construction. Results of geotechnical instrumentation and monitoring undertaken during the building construction are also discussed.

Jun 13, 2023

By Z. T. Bieniawski

Ground support requirements for safe and economical design of room and pillar coal mining layouts are reviewed. The design methods for mine roofs and mine pillars are discussed and the role of the geotechnical aspects is considered. It is shown that current support design procedures in the United States do not utilize fully the latest research findings and the need for more effective technology transfer in coal mine ground control is emphasized. Promising new developments in ground support are identified and possible research areas are suggested.

Jan 1, 1982

By L. B. Rothfeld

In anticipation of RCRA reauthorization and subsequent rulemakings, the Bureau of Mines is studying potential economic impacts of RCRA on mining. For U.S. copper heap and dump leaching operations in a variety of terrains, the cost of liners and closure caps to comply with RCRA Subtitle D ranges from $55 million to $158 million per site, or about $500,000 per hectare ($200,000 per acre). If RCRA technology requirements and financial assurance had been required on current operations, 27 to 100% of production from heap and dump leaching would have been non-competitive at market prices between $2,310 and $1,650 per metric ton ($1.047 and $0.75 per pound) copper. This result is based on an analysis that considers return on capital, corporate overhead, marketing, and freight costs as well as operating and maintenance costs at the mine. Over the same price range, economic analysis using the IMPLAN input-output model on one-or two-county regions indicates potential net job losses of about 570 to 2,700 jobs. Total economic output of those counties could be reduced by about $180 million to $360 million.

Jan 1, 1994

By M. Brändström, R. Dube, J. Moyo, T. Perkins, G. Bermudez, L. Bartsch, C. Smith, R. Sorensen

The Kennecott Copperton concentrator is currently the bottleneck for the Kennecott operation and several projects have been initiated to increase throughput. This increase in grinding circuit throughput has resulted in a coarser grind size which has impacted flotation circuit recovery. Metso Outotec 300m3 forced air tank flotation cells are currently utilized in the rougher flotation circuit at the Copperton concentrator. Higher overall recoveries have been observed on the newer Outotec tank cells compared to the original 85m3 self-aspirated flotation cells they replaced. However, coarse particle flotation response on these large, forced air cells did not show encouraging results when compared to smaller previously installed cells. This coarse recovery loss has been attributed to the longer froth transport duration and transport distance on large cells (100m3 and larger). Cell manufacturers addressed the risks of additional coarse particle losses in large cells by installing concentric circumferential launders and crowders (also called center launders). These are designed to reduce froth transport time and distance in the last cells in rougher stages where low residual floatable minerals causes a lack of froth mobility. The center launders also increase froth crowding, which also helps to increase froth transport velocity and increases copper and molybdenum recoveries. A trial set of the center launder retrofits were installed on the last three tank cells in one of the parallel rougher flotation rows at Copperton. The launder retrofits were installed at the end of October 2020 and monitored until March 2021. This six-month trial showed statistically significant improvements in copper and molybdenum flotation recoveries through the rougher circuit.

Mar 2, 2022

By Bruce R. Lipin

Chromite, the only ore of chromium, occurs almost exclusively in mafic-ultramafic rocks and their weathering products. However, not all kinds of mafic-ultramafic rocks are favorable hosts for possible low-grade chromite deposits. For instance, chromium-bearing basalts are not favorable because they commonly contain < 0.3% Cr2O3, and chromite is almost always less than 50 um in diameter, if it is present at all. Chromite-bearing ultramafic rocks in stratifonn and alpine complexes tend to be either ore grade (> 25% Cr203) or very low grade (< 2% Cr203); intermediate rocks are scarce. In most complexes large tonnages exist only in the < 2% Cr2O3 group and the composition of the chromite is commonly unsuitable for metallurgical use. Some nickel laterite districts contain more than 108 tons of material with 2.0% to 5.5% Cr2O3, and hence, chromium could be a byproduct of nickel in some laterite districts.

Jan 1, 1982

The purpose of this paper is to present validation studies of the mine-fire simulator using data gathered from an actual mine fire which occurred in November 1991 at the Pattiki Mine. To develop the model of the ventilation system with the fire in this validation study, the following adjustments were made: (1) flow and gas distribution in the entire ventilation network, and (2) fire parameters matching the data recorded by the monitoring system. After close correlations between simulation and real data were achieved, additional analysis of the ventilation system with the mine fire was performed. Presented and discussed in this paper are the following stages of the fire at the Pattiki Mine: (1) early fire (before the fire was detected), (2) preparation for and fire fighting with water, (3) fire sealing, and (4) fire extinguishing. This study evaluates the suitability of the computer software package for modeling underground fires. The paper also discusses the importance of the on-line monitoring system for the validation process.

Jan 1, 1995

By J. V. Thompson

The Powderhorn complex as a source of perovskite (calcium titanate) containing about 1.5% rare earths has been examined in several recent feasibility studies. Much promising exploration and process research has been done in recent years. This paper is presented with cautious optimism and with the acknowledgment that there may be some technical and economic areas yet to be explored. The Powderhorn carbonatite and alkalic stock in Gunnison County, Colorado, lies about 203 airlines km southwest of Denver at an elevation of 2450 to 2750 m (see Figures land 2). All of the mineable ore bodies are owned by Buttes Resources Company of Houston, Texas.

Jan 1, 1990

Flotation of dolomite from apatite was investigated, using dodecylamine hydrochloride or sodium oleate as the collector, in the absence and presence of inorganic modifiers such as sodium chloride. Separation of dolomite from apatite was anticipated from the single mineral experiments under various pH and collector concentration conditions. Flotation selectivity in the mixtures, however, was found to be limited. Attempts to control the flotation response of these minerals by addition of salts such as NaCI and KCI indicated that selectivity is possible. The presence of sodium chloride was determined to depress apatite flotation using sodium oleate leaving dolomite flotation unaffected (Moudgil and Ince, 1989). In this paper, conditions for optimum separation and the effect of major parameters on the desired selectivity are discussed.

Jan 1, 1990

By T. N. Moore, E. M. De Souza

Vibratory hand-tools can produce Hand Arm Vibration (HAV) Syndrome in their operators. This disease, often called Vibration White Finger, can cause varying levels of hand-arm discomfort and, in severe cases, impairment. In addition to the human suffering, there are also significant economic repercussions for industry. These include reduced operator efficiency, lost time through increased absenteeism and increasing compensation awards. In the mining industry, jackleg rock drills are a particularly troublesome source of hand vibration exposure. As a result, a significant amount of work has focused on redesigning rock drill handles to minimize hand-transmitted vibration. This paper details the results of a study undertaken to determine the effectiveness of using elastomer covered ("cushioned") handles in place of the standard steel design. The results indicate that, for a particular cushioned design, the overall acceleration level experienced at the hand-handle interface can be reduced by as much as a factor of three, relative to the steel handle. It is also shown that this reduction takes place predominantly in the frequency range above 500 Hz, with performance improving with increasing frequency. Qualitative evaluation of the cushioned handles by the drill operator indicates a significant increase in comfort over the standard steel handle.

Jan 1, 1992

By Leonard Bronitsky

The construction mineral aggregates industry--the largest industry on a tonnage basis--is threatened with large shortages in the near future. Ironically, these common minerals which include sand, gravel, and stone are among the most plentiful in the earth&apos;s crust. However, as these minerals are low in value and used in large volumes, they are extremely sensitive to transport cost, e.g., a haul of 20 miles doubled the delivered cost of mineral aggregates. Consequently, these minerals must be located close to points of demand to have economic usefulness. But the development of new deposits is virtually impossible near many urban areas for legal, sociological and economic reasons. The spector of unfinished urban transport systems, curtailed residential construction, and a general deterioration of the physical urban plant, looms as a direct consequent of future mineral aggregate shortages in the U. S. metropolitan areas. The shortages of mineral aggregates in the Greater New York Metropolitan Area (G.N.Y.M.A.) are prototypical of the shortages faced by the U. S. Metropolitan areas. This paper presents an economic analysis of the consequences of not considering the broad aspects of conservation economics as a major component of resource management. The needless annual cost for the G.N.Y.M.A. is shown to be $30 million.

Jan 1, 1974

By J. C. Ashby

Electric utility response to certain amendments of the Clean Air Act has resulted in a production of several types of alkaline coal combustion byproducts. Alkaline combustion byproducts are gaining increasing usage for acid mine drainage mitigation as research leads to a better understanding of their beneficial applications. Since January of 1997, Mettiki Coal Corporation has been injecting alkaline flue gas desulfurization material from Virginia Power&apos;s Mt. Storm Unit #3 wet limestone scrubber into abandoned portions of the active Mettiki mine. This paper provides an overview of the key design, transportation, regulatory, and environmental issues faced in the project.

Jan 1, 1998

By Christian Heinz, Doug Harding

TBMs can last for decades and be rebuilt project after project with proper maintenance. How successful can rebuilt TBMs be? At the DigIndy Tunnel System in Indianapolis, Indiana, USA, a rebuilt TBM was used to great effect. The 6.2 m diameter Main Beam, originally manufactured in 1980, bored 40+ km of tunnels and set three world records in its size class of 6 to 7 m, including a best month of 1,754 m. In this paper, the authors analyze the TBM rebuild, performance and lessons learned to make recommendations for future projects seeking to use rebuilt TBMs over long distances.

Jun 23, 2024

By C. Beul, R. Schipper, L. Santisteban

The Garfield Mine is a legacy vanadium mine in western Colorado with multiple mine openings, waste rock piles, and adit seepages that Cyprus Climax Metals Company (a Freeport-McMoRan Inc. subsidiary) voluntarily remediated through the Colorado Voluntary Cleanup Program (VCUP). The process to obtain a No Further Action determination from the VCUP is presented. Water treatment of the adit discharge, which is not part of the VCUP, is also presented. The remedial action objectives (RAOs) included preventing direct human or biotic exposure to the waste rock and radiation emitting from the waste rock; reducing metal concentrations and radionuclide activities in adit discharge and keeping the discharge from leaving the site; maintaining the existing undeveloped character of the surrounding landscape; and eliminating the need for a stormwater permit. The design included regrading, installation of an infiltration barrier and rock cover, a diversion channel, and a biologically based passive remediation water treatment system. An initial lab-scale evaluation provided design criteria for the full-scale system, which consists of a sulfate-reducing biochemical reactor and post-treatment aerobic polishing cells. The system has been operational since construction was completed in late 2016. Results indicate that the treatment objective of 90% bulk removal of constituents of potential concern (COPCs) is largely being met. The system also provides year-round operation and non-point discharge of effluent. After 20 plus years of site investigations, the remedial action was completed in 2016 with all RAOs met and a No Further Action determination granted in 2018. INTRODUCTION The Garfield Mine is a legacy vanadium mine located approximately 11 miles north-northeast of Rifle, in Garfield County, Colorado. It was leased and operated intermittently from 1929 to 1975 but was never operated by Cyprus Climax Metals Company (Cyprus) (a Freeport-McMoRan Inc. subsidiary). Prior to reclamation, site features included: • six mine openings—five adits and a vertical opening; • two adits discharging mining-influenced water (MIW)— Adit 1 at less than 4 liters per minute (L/min) and Adit 2 at 7 to 10 L/min; • main waste rock pile (13,500 m3) and small waste rock pile (minimal volume); • debris (small structure, mattress, bottles, shells, etc.) indicating site used for recreational purposes; and, • unimproved road, which has been used to access forest fires.

Jan 1, 2019

By Carl G. Bock

INTRODUCTION Rapid transit systems involving near surface tunneling in hard rock are becoming more numerous, especially along the northeast corridor of the East Coast. Tunneled systems are under construction in Washington, D.C. and are being planned for Atlanta, Buffalo and Baltimore. Near surface tunneling is defined for this paper as being that in which the crown is 100 feet or less below ground surface. For Rosslyn Station, the total cover ranged from 52 to 70 feet. The rock cover, however, ranged from 40 to 50 feet which is slightly less than the station height and about two-thirds of its width. Rosslyn Station (Fig. 1) is the only station excavated completely in hard rock in the Virginia portion of the 98.5 mile Washington Metropolitan Area Transit Authority&apos;s (WMATA) rapid transit system. The station site, oriented in a north-south direction beneath a main thoroughfare and flanked by multistory office buildings, was fixed by the need to serve a dense population center at a specific location and geologic conditions were a secondary consideration in siting. There was no previous underground rock excavation in the Washington Metropolitan Area of the size and scope of Rosslyn Station that offered a practical case history guide to the geologic conditions and excavation problems to be encountered. GEOLOGY The regional geology of the Washington Metropolitan Area is divided into two physiographic provinces by the northeast trending Fall Line (Fig. 2). Northwest of this boundary is the Piedmont Province

Jan 1, 1974

By P. R. Hervey, J. W. Foise

Quartz is the second most widely used electronic material, with approximately 3,000 t (3,300 st) of single crystals used each year. Most of the quartz used in electronics is synthetic and is manufactured using a technique called hydrothermal growth. This paper reviews the basics of hydrothermal growth, the feedstocks used for these crystals and the challenges to improving the growth process. This paper also reviews the processing of these crystals, the markets and applications where they are used, and the global outlook for these markets.

Jan 1, 2002

By Hiroyuki Tamaru, Futoshi Kusumoto, Kosuke Tanimura, Atsuyuki Kimura

"SUMMARY The Hachinoshiri tunnel is a 2,469 m long two-lane road tunnel on the Chubu-Odan Expressway. Since more than 70% of the total tunnel length consists of low strength rock masses the competence factor of which is less than 1.0, it is expected that a self standing span cannot be achievable because of no ground arch to be established. The tunnel was thus designed with tunnel support patterns forming multi-arc early ring closure that can develop the load-carrying capacity estimated from the exerted earth pressure, Po, which can result from the competence factor, cf. The tunnel support pattern was selected based on the competence factor at tunnel face, then the subsequent tunnel support patterns were determined with reference to the monitoring data. The tunnel construction adopted full-face excavation accompanied by early ring closure using a 330 kW road header. The proposed construction methods at this tunnel site have turned out ensuring tunnelling in massive squeezing rock, so that they can be verified as reasonable tunnelling technologies, clarifying the relationship between the characteristics of the mechanical behaviour of the tunnel and its design parameters. INTRODUCTION The presence of highly weathered mudstone having the competence factor less than 1.0 where the tunnel became unstable with the early ring closure having the distance to early ring closure, Lf, of 6 meters, resulting in difficulty in maintaining the inner section of the tunnel, prompted a substantial amount of high strength double support and replacing of the tunnel support (Sato et al., 2015). Based on the mechanical characteristics learned from the construction, the mechanical stability of multi-arc tunnels was investigated using 3D FDM analyses with respect to the ratio of the radius for early ring closure, r3/r1, and the distance to early ring closure, Lf, so that tunnel support patterns for early ring closure can be established in terms of the competence factor, of, which was employed for a 725 m long section. Consequently the tunnel support patterns for early ring closure which can be determined from the competence factor became applicable to tunnel construction. The relationship between the characteristics of the mechanical behaviour of the tunnel and its mechanical parameters was also clarified. The early ring closure method adopted ensured tunnelling in massive squeezing rock, verifying its effectiveness in stabilizing the tunnel."

Jan 1, 2016