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By Lee Ann Gardner

This U.S. Bureau of Mines publication presents a case study of the processes used in permitting the Nome Offshore Placer Project, a gold mining project offshore Nome, Alaska which operated from 1985 through 1990. The mining project, developed by Western Gold Exploration and Mining Company, Limited Partnership (WestGold), used the BIMA, which was at the time the largest bucketline mining vessel in the world, to dredge gold from the ocean floor. This case study reviews the permitting process from the regulators' and industry's perspectives, as well as characterizing the efficiencies and inefficiencies associated with this case. The Federal, State and local laws applicable to the Nome Offshore Placer Project are identified, agency jurisdiction and interagency relationships are explored, and the chronology of the permitting process is examined. The regulatory authorities for both environmental monitoring and post-mining monitoring are delineated. Significant milestones affecting the project and required regulatory submittals are also included. The case study of the Nome Offshore Placer Project is detailed with respect to agency involvement and coordination, approaches to permitting from both the regulators' and developer's perspective, environmental issues, and permit stipulations which were unique to the project. The advantages and disadvantages of these topics are discussed.

Jan 1, 1992

BRANCH COUNCILS Mining Branch E R Price, Chairman (Coal) Howard A Meyerhoff (Industrial Minerals) J V Beall, Secretary Richard M Foose (Industrial Minerals) Carroll F Hardy (Coal) Frank A Hardlaw (Mining, Geology, and Geophysics) S J Swainson (Minerals Beneficiation) Philip J Shenon (Mining, Geology, and Geophysics) Grover J Holt (Minerals Beneficiation) A C Callen (Mineral Industry Education) C H. Behre, Jr. (Mineral Economics)

Jan 1, 1952

By J. M. Mutmansky, Y. J. Wang

The usual method employed to determine the direction of flow in a connecting airway in advance is to conduct a survey between the two existing nodes being connected by means of the new airway. It is then assumed that airflow will take place from the node with higher pressure to the node with lower pressure. The purpose of this paper is to examine this direction-of-flow problem -- using properties of the system characteristic curve for a two-terminal network -- and specify some conditions that ensure that flow will take from the higher-pressure node to the lower-pressure node. It is concluded that the only requirement is that all characteristic curves of fans in the network should be strictly decreasing. Five numerical examples illustrate some important properties of the direction-of-flow problem.

Jan 1, 1999

By D. Hatfield

"Flotation plants typically aim to maximise recovery at or above a target grade. As the ore from the mine varies, operators increase or decrease the mass pull in different flotation banks by adjusting air and level set points in order to achieve target concentrate grade. A methodology has been developed to maximise overall recovery at target grade by determining the optimal mass pull for each bank. However, the approach of targeting equal grade for each ore type in the deposit leads to sub-optimal overall recovery. This is because some ore types sacrifice a large amount of recovery to reach target grade while others easily achieve target grade and can be processed at higher than target grade for little or no loss in recovery. Processing different ore types at different grades and blending the concentrates therefore gives a higher overall recovery.This paper presents a case study where an 80 year production forecast was made for a large Chilean copper concentrator in feasibility stage. A circuit model was created using SGS’s Integrated Geometallurgical Simulator (IGS) for the different ore types to be processed. The model was calibrated from standard rougher flotation tests (MFT), cleaner tests and from the results of plant surveys of similar operations. The pull rates for each bank in the circuit were determined to achieve an optimal graderecovery curve for each ore type. These curves were combined at different concentrate grades for each ore type to obtain the mathematically optimal overall recovery at target grade. The paper shows a methodology for obtaining an optimal combination of operating conditions for each ore type to maximise overall recovery at a set combined concentrate grade."

Jan 1, 2013

By McHenry Mosier

Mechanical loading, adopted long ago in open-pit, coal, and non-metal mines, was not used extensively in underground metal mines until the World War. In less than a decade it became standard practice in underground work in many mining districts. In 1924 the Missouri School of Mines and Metallurgy, in cooperation with the Federal Bureau of Mines, published a bulletin entitled "Mechanical Underground Loading in Metal Mines," which was prepared by Charles E. van Barneveld, mining engineer, Bureau of Mines.

Jan 1, 1940

The National Institute for Occupational Safety and Health (NIOSH) conducted a study to determine the effectiveness of a filtered air delivery system to reduce respirable dust exposure to roof bolter operators in underground coal mines. When performing roof bolting operations, roof bolter operators may experience exposure to high levels of respirable dust during a working shift, especially when working downwind of the continuous mining machine. While drilling and installing roof bolts, this filtered air system supplies a clean curtain of air over the roof bolter operator by means of a plenum mounted beneath the canopy. This experimentally designed air curtain, adapted for roof bolting machines used in this study, is based upon previous design prototypes, computational fluid dynamics (CFD) simulations, and trial-and-error testing. Both prototype and final designs were tested in the full-scale mining galleries at the Office of Mine Safety and Health Research (OMSHR) in Pittsburgh before being taken underground for field testing. Test results of the system in both laboratory and field studies show reductions in operator exposure to respirable dust when the operator is positioned directly under the protected zone of the canopy.

Jan 1, 2012

By Robert B. Fulton

Summary of data and estimates for 52 fluorspar properties in the following 13 foreign countries: Mexico Thailand China (PRC) Morocco Tunisia Italy Spain South Africa France United Kingdom Kenya Namibia Federal Republic of Germany Data includes deposit type, resource tonnage and grades, mining and beneficiation methods, annual production, fluorspar products and by-products, manpower requirements, capital and operating cost estimates. For operating properties, engineering and cost data have been developed for present and anticipated levels of production. Hypothetical operations have been assumed for undeveloped deposits.

Jan 1, 1984

By Bernardo Araya López

Dada la competitividad que existe en el ambiente empresarial durante los últimos quince años, las empresas reaccionan rápidamente ante los cambios del mercado. En este sentido, el presente trabajo señala el proceso de organización que la empresa debe considerar para lograr sus objetivos y metas. De forma, que la gerencia como concepto de gestión, genere confianza y responsabilidad sobre sus subordinados y potencie las habilidades de sus trabajadores.

Sep 13, 2001

A short account is given of the theory and practice of determining the true U3O8 content of ore samples by the determination of the beta and gamma activities separately, using the method of Eichholz and his associates.It is shown that, despite the variation of sample activity without change in U3O8 content, the true U3O8 value can still be found.Thorium can be determined simultaneously if this element is also present.

Jan 1, 1957

By S. Ilyas

Technical innovation in electrical and electronic equipment with new functions and design, stimulate consumer?s purchasing desire towards the latest equipments and this leads the rapid increase in the production of increased amount of waste materials Treason et al (2006) have reviewed the data on electronic waste generation in different parts of the world. Studies by Bertram et al (2002) have also affirmed that waste electrical and electronic components are the fastest growing waste category; this emphasizes the need for efficient recycling strategies. Recycling of electronic waste is an important subject not only from the point of waste treatment but also from the recovery aspect of valuable materials. However, recycling of electronic scrap is still quite limited due to the heterogeneity of the materials present in the products (Veit et al. 2005). A bioleaching based process offers a number of advantages compared to the conventional pyro or hydrometallurgical methods (Lee et al. 2007; Lee and Pandey, 2012). The advantages include simple, inexpensive (in some cases) and eco-friendly approach besides, generation of less active leach residue then other metallurgical processes. Though, biohydrometallurgical process has been successfully applied for the leaching of metals from ores (Olson et al. 2003; Rawling 2000), data pertaining to its application for the extraction of electronic scrap is still scanty. Recently, a few studies have been undertaken for extraction of metals from electronic scrap/printed circuit boards (Brandl et al. 2001; Faramarzi et al. 2004; Choi et al. 2004, Ilyas et al. 2007; Ilyas et al. 2010). These studies were conducted with mesophilic chemolithotrophic (Acidithiobacillus ferooxidans and Acidithiobacillus thiooxidans) or cyanogenic bacteria (Chromobacterium violaceum) or moderate thermophilic bacteria (Sulfobacillus thermosulfidooxidans). However, compared to bacterial leaching, fungal leaching has the following advantages: (i) ability to grow under higher pH, and thus is more suitable in bioleaching of alkaline solid waste (ii) a generally faster leaching process with shorter lag phase (iii) Chelation of excreted metabolites (e.g. organic acids) with metal ion, thus reduce its toxicity to the biomass (Burgstaller et al. 1993; Aung and Ting 2005). The specific objective of this work was to; ? Collection, isolation and enrichment of fungal strain ? Evaluate the abilities of Penicillium chrysogenum to leach metals from electronic scrap at various leaching modes (one-step bioleaching, two-step bioleaching, spent medium leaching, fresh medium leaching, leaching with deionised water and chemical leaching). ? Comparative study of all leaching modes

Feb 27, 2013

By J. C. Jansen

The platinum mining industry has experienced a significant increase in fatal accidents. Mine accidents are in principle preventable, and there is enormous pressure on employers to reverse this trend. This paper reviews safety management systems (SMS) as well as behaviour-based safety (BBS). Based on the review, SWOT analyses are performed on the SMS and BBS processes and a model of an integrated safety management system (ISMS) is introduced. A number of fatal accidents is analysed to identify factors that contributed to accidents in the mining industry. Thereafter the potential weaknesses of an SMS of a platinum mine are exposed and the potential benefits of implementing the ISMS for this case study are demonstrated.

Jan 1, 2005

By A. W. Breed

The bioleaching of arsenopyrite, the oxidation of arsenate and the precipitation of ferric arsenate are competing reactions, hence their rates depend on the relative concentrations of the respective species, and the activity of the bacterial culture. Bacterial arsenic resistance may be attributed to the Pst+Pit-mutation and an energy dependent efflux pump. Pst+Pit-mutations result in a reduced uptake of arsenate. This enables the bacteria to survive in solutions in which the arsenate concentration is significantly higher than the arsenite concentration. However, the excretion of arsenate requires energy. Therefore, in the absence of an energy source or during periods of reduced bacterial activity, the inhibitory effect of arsenate may manifest at concentrations to which the culture has been adapted. The chemical ferric leaching rate of pyrite and arsenopyrite decrease with a decrease in the solution redox and may be described using a modified Butler-Volmer equation. The bacterial ferrous-iron oxidation kinetics of L. ferrooxidans also depend on the redox potential, and can be described using a Michaelis-Mententype model modified to account for both temperature and pH. A model developed using the independently determined ferric leaching, and ferrous-iron oxidizing kinetics, has been shown to compare well with the experimental data for the continuous bioleaching of pyrite. Keywords: Leptospirillum ferrooxidans, arsenopyrite, bioleaching, sulphide minerals ferrous-iron oxidation kinetics, ferric leaching kinetics, redox potential

Jan 1, 2000

By Michel Rodrigue, Sylvain Duchesne, Louis Racine

"LocationThe Louvicourt mine is located 20 km east of Val d'Or in Abitibi, in the northwest part of the province of Quebec. The mine is located on Highway 117 connecting Val d'Or to Montreal and very close to the main railway networkHistoryFive successive exploration attempts by Aur Resources resulted in the discovery of the large Louvicourt orebody in June 1989. Construction of the surface and underground infrastructures commenced in the spring of 1991. Milling operations commenced in July 1994. The entire project cost CDN$290 million, almost CDN$20 million less than initially estimated. The concentrator infrastructure cost CDN$64 million.Louvicourt mine is owned in partnership by Novicourt Inc. (45%), Teck Corporation (25%), and Aur Resources Inc., the administrator (30%).Brief DescriptionLouvicourt mine is the largest producer of base metals (Cu and Zn) in Abitibi-Temiscamingue. Its average daily production is nearly 4300 t of ore, for an annual production of 200 000 t of copper concentrate (28% Cu) and 33 000 t of zinc concentrate (57% Zn). After only a few weeks of operation, it had attained its objectives for the most part, and operations continue to be improved."

Jan 1, 2000

By G. Howell, J. Wates, A. Coetzee, C. J. MacRobert

The Global Industry Standard on Tailings Management (GISTM) requires mining companies to make four key appointments as part of their tailings management structure. These four positions are an Accountable Executive with policymaking responsibilities, a Responsible Tailings Facility Engineer with operational responsibility, an Engineer of Record to ensure facilities are designed, operated, and closed safely, and an Independent Tailings Review Board to assess safety drivers regularly. Little guidance on the traits of these individuals is available in a South African context. Consequently, the tailings community of practice was surveyed to develop a table of ideal competencies and establish the flexibility in meeting these traits.

Jun 2, 2022

By G. W. Jones

In a previous report'/ results were given and a method outlined whereby from a knowledge of the composition of the natural gas and of the inflammability limits of the individual constituents composing the natural gas, the limits of inflammability of natural gas and air mixtures could be closely calculated. This method is based on the application of Le Chatelier's law as modified by Coward, Carpenter and Payman,5/ to apply to a mixture of any number of combustible gases. This law must not be used indiscriminately, because many exceptions have been found. For example, when ethylene, acetylene, hydrogen sulphide, or chlorinated hydrocarbons are present the law may not hold. For a discussion of the many exceptions which have been found, reference should be made to a report by Coward and Jones.6/

Jan 1, 1933

By S. J. Schatzel, W. P. Diamond, F. Garcia

Methane explosions have historically been one of the major causes of fatalities and injuries in underground coal mining operations. Advanced numerical models and predictive modeling approaches have the potential to offer optimized methane control solutions for general mine planning purposes and to address specific methane-related operational problems. This paper describes the development of reservoir models for the longwall mining environment and their application for investigating the influence of various completion design parameters on the methane drainage effectiveness of gob gas ventholes. The influence of increasing longwall panel width on the effectiveness of current gob gas venthole completion and placement strategies in the Pittsburgh Coalbed were evaluated and optimized designs developed to capture the expected increase in methane emissions on the larger panel.

By K. Short

Over the past several years, the mining and minerals market was overloaded with discussions around reviving mature terminologies like distributed control systems (DCS), programmable logic controllers (PLC), and the ?new comers?: hybrid control systems (HCS) and programmable automation controllers (PAC) and, in parallel, which technologies would be more appropriate for mining and mineral processing applications. Ten years ago, a careful comparative analysis would make more sense. Control approaches had very distinctive differences where users needed to choose the right approach.

Jan 1, 2012

By J. S. Hansen

To improve mine safety, the Bureau of Mines has conducted a search for better materials and systems to anchor roof bolts. This report describes a study on the ability of a gypsum-based anchoring medium to withstand short- and long-term loads. Results showed that 2-ft-long bolts anchored with gypsum that was injected as plaster slurry at a 0.370 water-cement ratio and cured for 10 min sustained pull test loads equal to the ultimate strength of the bolt steel (about 37,000 lb). For comparison, the minimum required capacity is 17,600 lb. Long-term loads of 15,500 lb were sustained with estimated 10-yr movement of less than 1/2 in. Two-foot-long bolts anchored with gypsum installed in a cartridge in which the water was contained in tiny capsules sustained a pull test load of about 30,300 lb at a 0.319 water-cement ratio and 10-min cure time. At a 0.288 water-cement ratio, load capacity was about 37,000 lb. The lower load capacities of cartridge-installed bolts resulted primarily from the remnants of the water-wax capsules. Above 10,000 lb, creep movement of cartridge-grouted bolts appears excessive, but longer bolts may be capable of resisting creep better.

Jan 1, 1985

By Roy G. Stott, John A. Johnson, Floyd G. Anderson

"This information circular discusses drilling and blasting in open-cut iron-ore mines and is one of a series of papers describing iron-ore mining practices in the Lake Superior district to aid in preventing accidents in that industry.The Lake Superior district consists of the Marquette and Menominee ranges of Michigan, the Gogebic range of Michigan and Wisconsin, and the Vermilion, Mesabi, and Cuyuna range of Minnesota. Open-cut mines produce 8o percent of the iron ore mined in the district; 98 percent of the total Lake Superior district open-cut ore is produced in Minnesota and 2 percent in Michigan. The entire Wisconsin iron-ore production is from underground nines. The Mesabi range in Minnesota produced 93 percent of the open-cut iron ore and 76 percent of the total iron ore in the district in 1947.During the 8-year period 1940-47, 619,000,000 gross tons of iron ore were shipped from mines of the district, or 85 percent of the United States output. Approximately 78,000,000 gross tons of iron ore were shipped from the mines of Minnesota, Michigan, and Wisconsin in 1947.This paper is based primarily on observations daring the period July 1947 to March 1948. Thirty-two open-cut mines were visited; 28 on the Mesabi range, 3 on the Cuyuna range, and 1 on the Marquette range. In 1947, 36,100,000 tons of iron ore was shipped from these 32 mines, or 59 percent of the open-cut ore and 46 percent of the total iron ore shipped from the district. During 1947 about 90 open-cut iron-ore mines were operating in the district, and the annual production of each ranged from 25,000 to 10,000,000 tons.Many recommendations included in this paper for improving safety and preventing injuries to employees were taken from Bureau of Mines Information Circular 7387.Data were collected under the direction of Frank E. Cash, former supervising engineer, Health and Safety Division, Bureau of Nines, Duluth, Minnesota. E. W. Felegy, mining engineer, Safety Branch, gave valuable assistance in reviewing and editing the manuscript.The authors gratefully acknowledge the information and assistance given and the numerous courtesies extended to them by officials of the following mining companies:All the Lake Superior iron ores occur in bedded formations that range from less than 100 feet to over 2,000 feet in thickness. These formations are designated by one commonly applied name, ""iron formations.""4/The Mesabi range in northern Minnesota, about 70 miles northwest of Duluth, was opened to mining in 1892; it is the largest single source of iron ore in the United States. It is 75 miles long and, because of the gentle dip of the ore formation, it ranges in width from 1-1/2 to 3 miles.5/ The ore formation, which is nearly horizontal, has a maximum thickness of about 450 feet and is covered by a glacial drift that ranges from 10 to over 100 feet in thickness. Most of the ore is near the surface and adaptable to open-cut mining."

Mar 1, 1950

By M. Dondelinger

This paper presents a comprehensive review of steel sheet piling including internationally manufactured hot rolled sections, their history, applications, installation and driving techniques. The discussion will cover both temporary and permanent installations; temporary piling used in construction of cofferdams with various bracing systems, deep foundation installations for buildings, bridges and tunnels, etc., and permanent piling used for highway, railroad and bridge construction as well as for riverbanks, piers, wharfs and docks, normally required for port facilities. In addition, cofferdams, as self-supporting gravity structures where interlock strength is of prime importance, will be discussed. The design and application of light, intermediate and heavy sections will be presented including heavy combined walls and information on Z-shaped, U-shaped and HZ sections and their corresponding interlocks. Emphasis is placed on new developments for design applications for deep foundations and waterfront structures within the "state of the art".

Jan 1, 2010