Search Documents

A mineral grain finder is described which is easily constructed to fit onto the stage of a standard reflected light ore microscope.The device is most useful in relocating particular grains or mineral associations on 30 mm diameter polished sections. The use of the grain finder in the teaching of ore microscopy is outlined.

Jan 1, 1988

By A R. Bye

Energy comes at great cost to our world and societies and therefore we should use it wisely and optimally. Societal pressure is enforcing this and the industry must respond by being proactive.The mine-to-mill approach to integrated mine and semi-autogenous grinding (SAG) mill optimisation demonstrated that throughput gains of up to 20 per cent could be obtained through a closer match of blasted run-of-mine ore to the feed best treated by a SAG mill. Since that approach was developed, new drivers have risen to prominence including environmental costs and impact of energy, water, waste. This is set against a backdrop of reducing ore grade and increasing demand that is pushing up our impact on the environment. The new challenges demand new approaches.This paper explores the opportunities in taking traditional approaches to optimisation to new levels of two-way integration and incorporating potentials for ore upgrade into circuit design. The new mantra may be æflexible circuitsÆ û designing and building for the present and the future by allowing for the uptake of new and future technology.

Jan 1, 2009

By C. Kunze

ABSTRACT Although closure sureties cover works that are carried out during the existence of a mining company, certain liabilities are not known when the surety is established and become apparent only in a late stage of the closure phase, or even after the site has been relinquished. This paper supports the concept that these financial risks lend themselves to insurance solutions. Making insurance for unknown liabilities mandatory while defining unambiguous legal conditions could create a viable market for insurance products, provide a sufficient statistical basis for the calculation of premiums, and reduce costs.

Jan 1, 2013

By Walter D. Holland

This is one of a series of instruction guides developed to help instructors present health and safety training courses to workers in the coal mining industry. This course is intended for training those, usually the safety officers, who perform surveys fur inhalation contaminants in above ground work areas. The handbook entitled ?Handbook for Surveys of Inhalation Contaminants in Above Ground Coal Mining and Processing Work Areas? (NTIS #PB-243-35";) is used as a manual for the course and as a prime reference when performing the actual surveys or interpreting the sampling results. There are six experiments for the students to perform during the course to familiarize them with the sampling devices routinely used during the surveys.

Jan 1, 1976

By John C. Holtz

"The Federal Bureau of Mines serves the mining industry by approving equipment that is designed to prevent explosion, fire, shock, or toxic hazards in mines when such equipment is used and maintained in a proper manner, through research, consultation, testing, and inspection, the Bureau studies machinery and component parts submitted by manufacturers and others. Before receiving the Bureau's approval as permissible for safe use in mines, equipment must pass exacting tests and must meet strict requirements established through research and experience and listed in the Bureau's various permissibility schedules. An important phase of the Bureau's research is the testing of diesel engines.Mobile diesel-powered equipment can be used safely in underground noncoal mines and tunnels when mechanical ventilation is provided to dilute and remove the exhaust gas and to replenish oxygen in the underground atmosphere. Safe ventilation is determined by suitable tests of each engine used in a diesel machine. This ventilation cannot be predicted safely, accurately, and economically from any general empirical relationship.In determining safe ventilation, the quantities of carbon dioxide, carbon monoxide, and oxides of nitrogen generated by a diesel engine must be ascertained. These quantities are related to the displacement of the engine, its speed of operation, the design of the combustion chamber, and the fuel:air ratio needed to produce useful power. At overrich fuel:air ratios, all diesel engines generate excessive quantities of toxic carbon monoxide and smoke. The results of engine tests are used to determine a maximum fuel-injection rate at or below which carbon monoxide can be controlled by a reasonable ventilation and smoke is essentially eliminated. Toxic oxides of nitrogen are related to fuel:air ratio and the design of the combustion chamber. Their concentration in the exhaust cannot be controlled by engine adjustments, and each engine appears to have individual characteristics concerning formation of these oxides. Production of oxides of nitrogen frequently is the most important factor in determining safe ventilation."

Oct 1, 1959

By J. A. Abols, P. M. Grady

Recovery via gravity is one of the oldest mineral processing methods available. Unfortunately, the use of gravity techniques for gold recovery has been in decline for the past century as more effective chemical processes such as flotation and leach/CIP have been developed. Recently, with the push towards more sustainable environmental outcomes, the benefits of gravity separation have become more apparent. While gravity as a unit process is not usually capable of achieving as high a recovery as flotation or whole ore cyanidation, a combination of gravity devices alone or in conjunction with these processes can offer significant advantages to the operator. This paper reviews the range of gravity devices available, their application and the results that can be achieved by maximizing gravity through the use of a combination of gravity recovery devices. Three case studies are provided.

Jan 1, 2005

By Gary Jobson

The Mt Todd Gold mine is situated near Katherine in the Northern Territory of Australia. Commissioning of an 8 Mtpa processing facility incorporating a four stage crushing circuit, ball mills, flotation, concentrate regrinding, high rate thickening and CIL processing was commenced during late 1996. A 4.5 M tonne /annum crushing and heap leach facility was commissioned during late 1994, and was subsequently upgraded to a nominal 6 M tonne / annum circuit during 1995. Processing equipment used included primary gyratory, secondary cone and tertiary Barmac VSI crushers. Some of the features of that crushing circuit and heap leach facility were presented at the Randol Perth 95 conference by myself. The location is described as sub tropical with average climatic conditions including 1100 millimetres annual rainfall, predominantly during the December. to March wet season, and 3000 millimetres evaporation and maximum temperatures ranging from around 26 to 46 °C. The main gold occurrence at the Mt Todd site is the Batman deposit, with current published Reserves of some 60 Mt@ 1.20 g Au / tonne ( 0.0425 oz Au / ton ). The primary ore from the Batman deposit is an extremely competent greywacke and is very hard at an average Bond Ball Mill Work Index of26.5 kWhrs/ tonne. Other indicators include a Bond Impact Crush Work Index of 20 kWhrs I tonne, an Abrasion Index of 0.15 and Ultimate Compressive Strength values of 100 - 200 MPa. The main gold occurrence is very finely disseminated free gold (at an average grain size of around 5 micron) within a combination of quartz and mixed sulphide. This gold bearing component is confined to largely parallel veins ranging from 0.5 to 25mm wide within a greywacke matrix. Although the gold is essentially non­refractory, there is a strong recovery versus grindsize relationship due mainly to the liberation characteristics and the relatively low permeability of the host greywacke rock.

Jan 1, 1997

By E. H. Burroughs

This bulletin is the sixth in the series of petroleum bibliographies published by the Bureau of Mines, Bulletins 149, 165, 180, 189, and 216 being compilations for the years 1915, 1916, 1917, 1918, and 1919- 1920, respectively. In this bulletin the same general plan has been followed in arranging the references, but one or two additions have been made in the classification.

Jan 1, 1921

By Russell R. McLellan

Under the Heavy Metals Program, investigations were conducted at the old Badger dill placer mini in Nevada County California to collect data and information regarding drilling and sampling methods and deposit characteristics. The studies contributed to a team effort by five Bureau of Mines research groups to develop new or improved placer mining technology in the Tertiary gold-bearing channel gravel of northern California. This report describes the techniques used and the results obtained in the sampling and drilling stage of deposit delineation studies that were conducted by the Denver Mine Systems Engineering Group. Sampling included the collection and processing of 400 tons of largo and small volume samples from drill holes, underground workings, surface pits, and blast hole rounds. A total of 355 samples averaging 2,296 pounds per sample provided reasonably accurate data for analysis of the gold distribution. These studies indicate that the bulk of the gold is within 40 foot of bedrock in stacked, lenticular zones of cemented gravel that are largely confined to the relatively narrow, meandering course of the deepest portion of the bedrock channel. Drilling studies involved the testing of three types of truck-mounted drills including rotary, bucket and vibratory, none of which proved to be a completely versatile tool for sampling quickly and reliably both consolidated and unconsolidated gravel.

Jan 1, 2012

By A. Duerksen

Surface coal mining in West Virginia has supplied energy to the eastern coast of the United States for over a century. The coal mining industry has been forced to adapt as societal demands regarding health, safety, and environmental impacts have changed with time. More recent pressure has called for another iteration of change: long-term post-mining sustainability. The research presented in this paper investigates one potential solution?or component of a solution?to improve mining sustainability in Appalachia: post-mining wind power. This paper intends to demonstrate and explain the feasibility of synergistic mine closure and wind development. Wind conditions at three reclaimed mine sites in West Virginia were monitored in order to develop representative case studies for post-mining wind power. This paper contains a summary of the literature consulted to plan the site assessments, the methodology employed to execute them, the analysis steps undertaken to derive conclusions, and a discussion of all findings. This research has found that significant cost savings can be yielded from synergistic mine closure and wind development, as compared to greenfield wind development. Though wind conditions themselves remain the primary driver for site feasibility, post-mining wind power is a practice with significant promise for improving project economics, contributing to renewable energy development, enhancing company-community relations, providing local employment opportunities, and exemplifying sustainable business practices in Appalachia.

Jan 1, 2012

By J. H. Crary

This report summarizes the results of a one-year agreement for research on the electromagnetic environment in coal mines, which was conceived as the beginning of a long term cooperative program between ITS and the Bureau of Mines. The concepts on which it was originally based are a result of the report on mine rescue and survival by the Committee on Mine Rescue and Survival Techniques of the National Academy of Engineering, dated March 1970. This report drew particular attention to the need for improved communications during and following mine disasters. In particular, the outstanding problems identified were the location of, and communication with, trapped miners. Some tentative solutions, generally involving long-wave electromagnetic signals, were offered. Consideration of the problems of disaster location and communication soon leads to consideration of the communications techniques (or lack of them) for use under normal mining conditions. In particular, if a disaster communication and/or location system is to be readily available and operable under disaster conditions, it should also be usable during mining operations. In this way operators can become familiar enough with the system to operate it during disaster conditions, as well as provide a mechanism for regular testing.

Jan 1, 1972

Albin. B . R Billings. Mont . '28 Amnter . Nathan L 26 Broad St.. New York . N . Y . '28 Bache . Jules S 42 Broadway. New York. N . Y . '28 Borrett . C . P . 5338 Harper Ave .. Chicago. I11 '28 Baum . Frank G. . Cons . Hydro-Electric Engr Camel'. Shasta Co. . Cal. '23 Baylean, William S Russ Bldg .. San Francisco. Cal . '28 Bean, Louis H .. V.P.. Dwight P . Robinson & Co.. lnc 126 E . 46th St New York. N . Y . '28 Beatty . Roes J . 1106 First National Bank' Bldg .. Chicago . Ill . '28 Benwell . Oswald F . 110 Gilpin St .. Denver. 1310 . '28 Beymer. Albert 9.. V.P .. Keystone. National Bank Pittsburgh. Pa . '28

Jan 1, 1929

[Secretary's Note.—The following official tables, prepared by the government of the State of Nuevo Leon, and presented to the Institute at the fifth seseion of its Mexican meeting, held at Monterrey, November 26, 1901, present in compact form a general summary of the mineral and metallurgical industry of the State for the preceding calendar year, together with a statement of the railway-shipments of ores from January 1 to October 31, 1901, which, in the absence of direct official mining and metallurgical statistics (not yet available for that year), clearly indicates an increased activity and productiveness of these industries. In other words, the mines are reported to have yielded in 1900 a total product of 83,960,169 kilos of ore; whereas, the railway is reported to have carried, in 10 months of 1901, a total of 108,318,647 kilos of ore. At this rate, the railway-shipments for 1901 mould amount to nearly 130,000,000 kilos. It is, of course, possible that the railwaystatistics include other freight than ores, or that they include duplications, such as would be involved in the record, first of certain ores transported, and afterwards of the " base bullion " produced therefrom. An accurate comparison is therefore impossible ; yet, after making all reasonable allowances for such items as have been named, it seems safe to infer that the mining and metallurgical industry of this State accomplished in 1901 a substantial progress.]

Jan 1, 1902

By W. C. Brice

A cooperative study was undertaken by representatives of the environmental community, the mining industry, and state government to identify and resolve environmental issues associated with base and precious metal mining in a neutral atmosphere before a commercial mining development is announced. The study included testing Minnesota's as-yet-untried non-ferrous mining regulatory program using three hypothetical mining developments sited in environ-mentally sensitive areas where future mining could occur. Results include identification of critical paths for regulatory decision making, identification of particularly sensitive environ-mental issues that will need continued deliberation before resolution, and characterization of data necessary for environmental review and permitting decisions.

Jan 1, 1990

By Thomas P. Battle

Modern-day direct reduction of iron first developed as a small-scale, low capital and operating cost alternative to the blast furnace. Since commercialization of continuous DR technology in the late 1960s, the market for the products of direct reduction has grown to more than 74 million tonnes in 2012. The initial advantages of DR plants over BF facilities have grown over the years, for several reasons, including the increased size of DR modules, lower energy and emissions (particularly CO2), along with the flexibility to use a number of different reductants. The development of DR technology over the past forty years will be emphasized in this presentation, including recent developments that allow for even more direct sustainability comparisons with the iron blast furnace – and even combine the two technologies for improved synergies. Also briefly discussed will be the possibilities of using direct reduction for non-ferrous ores.

Jan 1, 2014

By L. C. IlsLey

A list of permissible mine equipment, tested and approved p or to July 1, 1934, was published in Bureau of Mines Information Circular 6813/. The present list4/ includes virtually all the electric air compressors, coal drills, mining machines, loading machines, conveyors, mine pumps, room hoists, mine telephones, rock-dusting machines, switches, electric cap lamps, flame safety lanes, electric hand and trip lamps, electric flood lamps, methane detectors, blasting units, storage-battery locomotives, tandem locomotives, mower trucks, and concrete mixers tested and approved by the Bureau to January 1, 1937. The system under which these devices were tested permits the manufacturer, after his equipment has passed certain tests prescribed by the United States Bureau of Mines, to mark his equipment with a seal showing that it has been approved by the Bureau. These tests are designed to insure that equipments have the minimum requirements for safety in use. The only object of the bureau in making such tests and publishing lists of permissible equipment is to help decrease the hazards of mining.

Jan 1, 1937

An index covering the papers presented at the 19 Open Hearth Conferences from the first meeting at Pittsburgh, April 15 and 16, 1925, through the most recent meeting in Detroit, April 16 and 17, 1936, the reports of the meetings and the discussions that took place has been published, accompanied by a list of the papers presented, grouped by subject matter and a list of books of interest to open hearth men The list below gives the Open Hearth Conference meetings in chronological order and the symbols used to designate them in the index SYMBOL MEETINGS P25 Pittsburgh, April 15 and 16, 1925 C125 Cleveland, Oct 13 to 15, 1925 Ch26 Chicago, April 12 and 13, 1926 P26 Pittsburgh, October, 1926 B27 Buffalo, May 3 to 5, 1927 D27 Detroit, Nov 2 and 3, 1927 Y28 Youngstown, May 3 and 4, 1928 P28 Pittsburgh, Nov 15 and 16, 1928 C129 Cleveland, May 16 and 17, 1929 Ch29 Chicago, Nov 5 and 6, 1929 B30 Buffalo, May 20 and 21, 1930 C130 Cleveland, Nov 20 and 21, 1930 Ch31 Chicago, May 12 and 13, 1931- D31 Detroit, Nov 24 and 25, 1931 P32 Pittsburgh, May 24 and 25, 1932 Ch33 Chicago, June 29 and 30, 1933 P34 Pittsburgh, June 28 and 29, 1934 C135 Cincinnati, April 11 and 12, 1935 D36 Detroit, April 16 and 17, 1936 The list of papers mentioned in the first paragraph above is reprinted on pages 428 to 431 The Index of the Open Hearth Proceedings may be purchased at A I M E headquarters, 29 W 39th St, New York

Jan 1, 1936

By Galen H. Clevenger

Although there are exceptions, oxidized silver ores containing the higher oxides of manganese are generally refractory to hydrometallurgical methods of treatment. When these ores are of high enough grade they can be smelted; indeed, some rather low-grade ores of this type have been smelted at a profit because of their fluxing value. In the past, when these ores could not be smelted, they either were not treated or were treated at low efficiency, generally by cyanidation. The need for thorough investigation of the problem was therefore evident for some time before the writers began their research. The problem of treating manganese-silver ores seems to have been recognized first about 35 years ago by C. W. Goodale in applying pan amalgamation at Tombstone, Ariz. He attributed the low extraction of silver to the fouling of the mercury by manganese rather than to the presence of a refractory compound of manganese and silver. Although definite knowledge as to the cause of the poor extraction of silver was lacking, a more or less effective preliminary treatment, that is, a chloridizing roast, was applied.

Jan 1, 1925

By Raymond L. Lowrie

Coal deposits in the Boulder-Weld County coalfield in Colorado are analyzed in relation to economic factors governing the growth, stability, and competitive potential of the coal industry. Recoverable reserves, estimated to be 571 million tons, are discussed in detail, particularly those in the Erie and Frederick Quadrangles. Geology of the coal measures, quantity and quality of water resources, and chemical and physical properties of the coal are described. Coal production factors, including mining techniques and equipment, labor requirements, transportation facilities and rates, and markets, are considered for coal's position in competition with alternate fuels. Growth of the fuels market, through increasing thermal-electric power generation in the Denver Metropolitan Area, will stimulate coal production in Colorado. Reserves of the contiguous Boulder-Weld coalfield, if mined in a sustained, year-round, high-tonnage operation, could be used to supply much of that fuel demand.

Jan 1, 1966

By Michael J. Beus

This Bureau of Mines report describes a field experiment involving the sinking of two test shafts to directly compare the deformational behavior of circular and rectangular shapes. Results show that the circular shape is less sensitive to geologic discontinuities and applied stress field. Also, the rectangular shape is subject to a variety of behavioral modes, including beam bending and buckling. Geologic discontinuities around circular and rectangular shapes influence displacement significantly. Simple, two-dimensional elastic finite-element modeling, simulating circular and rectangular shapes in a biaxial stress field, shows that the structural response of a shaft is largely controlled by geologic structure. Consideration of anisotropy may be required for realistic analysis of a deep shaft.

Jan 1, 1985