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By Jasinder S. Jaspal

In underground room-and-pillar mining methods, the sectional conveyor belts are extended or retracted periodically to maintain shuttle car tramming distance to a minimum. A conventional conveyor belt extension or retraction is a heavy, arduous job that if mecahnized, has the potential to improve productivity and safety. To reduce the burden of heavy work of this activity and mechanize it, the Bureau of Mines developed a conveyor belt service machine (CBSM) through a research contract with Tractor MBA. The CBSM is a self-contained, battery-powered, rubber-tired vehicle capable of handling, storing and transporting conveyor belting, wire rope, and associated belt structures in seams as low as 48 in. Belt extensions and retractions are accomplished by moving the tailpiece of a belt conveyor with the CBSM to the next position while dispensing or retrieving the belt, wire rope, and associated belt structures. The CBSM improves the belt extensions and retractions by making them easier and faster, and it utilizes fewer workers. The CBSM was surface tested at the Bureau's Mining Equipment Test Facility (METF) to evaluate its performance and reliability. Modifications were made to the CBSM to correct deficiencies found during surface testing.

Jan 1, 1988

By J. R. Cobble

Dissolution of chalcopyrite with acidified ferric sulfate produces a sulfur layer on the unreacted chalcopyrite surface that interferes with further dissolution. The U.S. Bureau of Mines has developed a process to improve the leaching kinetics of these types of diffusion-controlled systems. The system features the Bureau-developed turbomill, an attrition grinder that scrubs the reaction product coating away from the unreacted mineral grains during leaching. The system can be operated continuously at any temperature up to the boiling point of the leaching agent. This method is a hydrometallurgical alternative to chalcopyrite smelter technology and eliminates sulfur dioxide emission problems with its associated costs. Batch testing at 900 C with the chalcopyrite-ferric sulfate system resulted in copper extraction exceeding 99 pct. At an optimal energy consumption of 1,520 kW· hjst, 95 pct of the copper was extracted. The pregnant liquor was clarified and tested for typical solvent-extraction recovery of the copper. Two-stage extraction and two-stage stripping recovered 96 pct of the copper in an electrolyte suitable for copper electrowinning.

Jan 1, 1993

By Paul T. Allsman

This paper describes metal- mining practices at the Harrington -Hickory lead - silver - zinc mine at Milford , Beaver County , Utah . The operations of the Harrington-Hickory incorporate a number of features that should prove of interest and value to other operators of small mines . These features include employee participation in profits , a well- laid -out electrical system, adequate financing , a well - balanced equipment and supply inventory , a well - organized system of bookkeeping , adequate roads , and good management . As crude ore is shipped directly to smelters and mills in the Salt Lake Valley , close attention is paid to see that the ore is segregated by classes and treated where it can bring the greatest not return . A combination of these features has resulted in maintaining relatively low costs, considering the grade and size of ore shoots at a time , during and following the war , when equipment , supplies , and labor were costly and difficult to obtain . The period covered in this report includes two war years and two years following , from April 1, 1944 to June 30 , 1947 .

Apr 1, 1949

Possible consequences of continuing internal political unrest and the imposition of foreign sanctions raise concerns about the traditional reliability of the Republic of South Africa as a major world supplier of important minerals. A recent Bureau of Mines' technical report (Open File Report 76-86) examined the impacts of temporary peacetime disruption scenarios for six key materials and mitigating options. Because of South Africa's dominant producer position for these minerals (except for cobalt), expansion of primary production capacity outside of South Africa is not a short term mitigative option. However, prospects of a longer term disruption would likely spur investment in capacity expansion in alternative Market Economy Country supply sources. This report identifies the resources, production costs, and burdens that would be placed on alternative MEC producers of chromium, cobalt, gold, manganese, and platinum-group minerals if South Africa's production were subject to a long term; disruption. When long term supplies from South African deposits are discounted, more than a few years reserves were found only for cobalt and manganese. Even for these two minerals, higher sustained prices would be required to increase manganese production capacity and to support means of cobalt transportation not through South Africa.

Jan 1, 1986

This manual provides instructions for installing, operating, and maintaining a protective canopy on the Joy Mfg. Co. loader. These instructions are based upon two actual install .at ions: one made in a mine on loader, model 14BU10-11AH, and one in the factory on model 14BU10- 11AH. The parts list and engineering drawings for the protective canopy are included at the end of the manual. And a discussion of some alternative design concepts is also included. The manual can also be used for retrofitting other loaders with similar protective canopies. Skilled mechanics can determine if the instructions herein would be applicable to the other loaders and can determine any necessary modifications if they are not.

Jan 1, 1973

By J. H. Holden

The Federal Bureau of Mines is doing research and development work on a pressure-gasification pilot plant for producing synthesis gas directly from pulverized coal, oxygen, and steam. A pressure-gasification pilot plant has been constructed, and an investigation was made with the following basic objectives: 1. Determining the effect of varying pressure (75, 100, 150, and 300 p.s.i.g.), coal rate (400, 700, and 1,000 pounds per hour), and oxygen-to-coal ratio (8 to 11 std, c,f. per pound), on percentage of carbon gasified, oxygen and coal requirements per unit of CO + H2 produced, exit-gas temperature, and heat loss. The steam-to-coal ratio was maintained at approximately 0.3 pound per pound. 2. Development of a stabilized gasification zone or reaction space. 3. Improvement in operability of the pilot plant.

Jan 1, 1960

By E. J. Ostrowski, P. L. Woolf, J. P. Morris, Norwood B. Melcher

By injecting natural gas through auxiliary tuyeres into the smelting zone of the Bureau of Mines ' experimental blast furnace in January 1959 , the investigators succeeded in reducing the coke consumption by approximately one - third that of the base period . This caused a 30 - percent increase in pig iron production with no increase in wind rate . The maximum gas addition in these experiments was 4,665 cubic feet per ton of metal produced . Sharp reduction in gas consumption occurred when high hot blast and high wind rates were used , although the gas injection rate in percent of air blown remained constant . As the heat energy produced by burning natural gas to carbon monoxide and hydrogen is much less than burning coke to carbon monoxide , greater blast temperatures were required during the test runs . The gases produced from the methane were , however , more effective reductants ; so it was possible to increase the production rate while reducing the total heat requirements per ton of metal produced . During a base period with an all - sinter burden , before introduction of natural gas , a coke rate of 1,484 pounds per net ton of pig iron was attained , using an average blast temperature of 1,518 ° F. Gas was introduced gradually over a two -week period until an average 7 percent of the air blown was reached . During this period , the wind rate was adjusted downward to maintain a constant flow of gas in the bosh . The production rate of the furnace remained relatively constant . The quality of pig iron, however , improved as the sulfur load on the furnace was reduced as a result of the substitution of gas for coke . Blast temperatures were increased during this period from 1,518 ° F. to 1,939 ° F. , when the maximum gas addition was reached .

Jul 1, 1960

By B. K. Cantrell, K. L. Rubow

"Two source apportionment techniques have been applied by the U.S. Bureau of Mines to aerosol measurements in diesel-equipped underground noncoal mines. The first technique is based on size-selective sampling and the premise that the diesel exhaust fraction of the aerosol is predominately submicrometer in size while the mineral dust fraction of the aerosol is mostly supermicrometer in size. The second technique, chemical mass balance (CMB) modeling, was used to referee the analysis of diesel and mineral dust aerosol concentrations with the size selective method.The size-distribution data were modeled using a lognormal regression to parameterize the submicrometer and supermicrometer fractions of the sampled aerosol and to estimate the mineral and diesel contributions to each. Using this analysis, 97 ± 2 pct of the submicrometer aerosol mass was attributable to diesel exhaust aerosol.The CMB analysis, applied to both fractions of the respirable mi11e aerosol, yielded the amount contributed to each by the diesel and dust aerosol sources. On the basis of this analysis, 94± 10 pct of the submicrometer fraction was diesel exhaust aerosol. As much as 20 pct of the diesel aerosol, however, was found in the supermicrometer fraction, requiring a correction of the submicrometer fraction results to account for the missing diesel mass. More accurate measurements will require a carbon-specific analysis of the aerosol.INTRODUCTION Measurement of the contribution of diesel exhaust to respirable aerosol in mine environments has become increasingly important because of current concerns over the occupational health effects resulting from exposure to diesel emissions. In response to this, the U.S. Bureau of Mines is developing and evaluating new sampling methods for measuring diesel aerosol in underground mines. Two such techniques are being studied by the Bureau, size selective sampling and CMB modeling. These techniques use measurable physical or chemical characteristics of a mine aerosol sample to infer the amount of diesel particulate material contained in the sample."

Mar 1, 1992

By A. T. Harris

Ground quartzite, known in the industry as amorphous silica, is produced from a quartzite deposit near Honey Brook, Pa., by George F. Pettinos, Inc., of Bala-Cynwyd, Pa. The quartzite is mined by the open pit method and processed in a mill at the mine. The operation regularly produces five standard grades of sand and one grade of crushed stone; however, the company accepts special orders and will produce material to meet the customer's specifications. Beneficiation (chiefly crushing and screening) is controlled by laboratory screen tests on samples taken during preparation of the sand. The chief uses of the sand are for foundry operations, furnace lining, concrete aggregate, and Other specialized uses. The quartzite in this deposit is of uniform composition and does not require control by chemical analysis. However, for special purposes, analysis will be furnished.

Jan 1, 1965

By A. T. Harris

Ground quartzite, known in the industry as amorphous silica, is produced from a quartzite deposit near Honey Brook, Pa., by George F. Pettinos, Inc., of Bala-Cynwyd, Pa. The quartzite is mined by the open pit method and processed in a mill at the mine. The operation regularly produces five standard grades of sand and one grade of crushed stone; however, the company accepts special orders and will produce material to meet the customer's specifications. Beneficiation (chiefly crushing and screening) is controlled by laboratory screen tests on samples taken during preparation of the sand. The chief uses of the sand are for foundry operations, furnace lining, concrete aggregate, and other specialized uses. The quartzite in this deposit is of uniform composition and does not require control by chemical analysis. However, for special purposes, analysis will be furnished.

Jan 1, 1965

By J. R. Koehler

Effective barrier pillar design is essential for safe and productive underground coal mining. This U.S. Bureau of Mines report presents an overview of available barrier pillar design methodologies that incorporate sound engineering principles while remaining practical for everyday usage. Nomographs and examples are presented to assist in the determination of proper barrier pillar sizing. Additionally, performance evaluation techniques and criteria are included to assist in determining the effectiveness of selected barrier pillar configurations.

Jan 1, 1995

By D. H. Carlson

The U.S. Bureau of Mines and Michigan Technological University (MTU) are collaborating to develop an apparatus for measuring diesel tailpipe emissions in underground mines. A tailpipe emissions measurement apparatus (EMA) is described that dilutes diesel exhaust and measures the concentrations of diesel particulate matter (DPM), CO, CO2, NO, and NO2 at known dilution ratios. The EMA was evaluated by side-by-side comparison of its measurements with those by laboratory-grade instruments. Concentrations of CO and CO2 measured by the EMA were usually within ± 14 pct of concentrations measured by laboratory-grade instruments for CO and ±20 pct for CO2. EMA¬ measured DPM concentrations were, on average, 29 pct lower than those measured by laboratory-grade instruments, with the differences being fairly consistent. The CO and CO2 differences are related to the method of calculating the EMA's dilution ratio, and the difference in DPM concentrations is attributed to thermophoretic and/or condensation losses related to the EMA's unheated sample probe. Preliminary analysis of data obtained with a heated sampling probe and modifications in the sampling procedures have indicated reduced variability in DPM and in the calculated dilution ratios.

Jan 1, 2010

By Charles G. Patmon

This paper describing the methods of dredging and treatment of gold-bearing gravels at the Lancha Plana Gold Dredging Co.'s dredge is one of a series of similar papers being prepared by the Bureau of Mines on mining practices, methods, and costs in the various mining districts of the United States. The dredge is located near the Mokelumne River, 12 miles west of San Adreas, Calif.; it is accessible by an improved dirt road from Jackson, which is about 20 miles distant.

Jan 1, 1932

By F. S. Wartman

The presence of magnetite, either dissolved or suspended as solid crystals, in slags from the copper reverberatory furnace is a frequently mentioned cause of an abnormally high copper content in those slags. The presence of this oxide in the slag is to be expected, since it is present in appreciable amounts in both converter slag and roaster calcine which comprise a considerable proportion of the furnace feed. Magnetite is also a product of some of the furnace reactions. These abnormal losses result in several ways. Magnetite is supposed to favor the formation and retention of copper ferrite, in the slag. Crystals of solid magnetite suspended in the slag are objectionable-because they make the slag less fluid and often entrap globules of matte. Frequently these crystals settle into a layer at the slab-matte interface which may have such mechanical strength as to create a false bottom and interfere with furnace operation by preventing separation of matte from slag. Magnetite may, by crystallizing on the furnace bottom, build the bottom to such a level that the furnace can no longer be operated.

Jan 1, 1928

By L. G. Marshall

This report, describing the mining method of the Dresser Trap Rock Co., Dresser, Wis., is one of a series published by the Bureau of Mines on mining methods, performance, and costs at mining operations throughout the United States. SUMMARY Dresser, in Polk County, is 3 miles south of St. Croix Falls, Wis. Company operations are about 1 mile north of the townsite. The mine has been in [peration] since 1914 and under the present ownership since 1949.

Jan 1, 1959

By R. R. Sayers

Radioactivity, the property of radium that led to its isolation more than 30 years ago, is the characteristic that makes it of value in the treatment of disease. Tyler3 gives the following brief history of the investigation: The way to the discovery of radium was opened in 1895 by Rontgen, who found that the glow from a Crooke's tube contained penetrating rays, which .he called X rays. Prof. Henri Bequerel, while investigating the effect of various phosphor¬ escent substances, found that uranium salts produced photographic impressions even when enveloped with opaque substances. To Marie Sklovouski, a young Polish student, who later became Madame Curie, Professor Bacquerel delegated the task of learning how and why uranium possessed power to emit these peculiar rays, which he had proved to be electrical in character. Madam Curie, examining by electri¬ cal methods the radioactivity of a large number of minerals containing uranium and thorium, discovered that some specimens of pitchblende had about four times the activity of the metal uranium; that chalcolite, the crystallized phosphate of copper and uranium, was twice as active as uranium; that autunite, a phosphate of calcium and uranium, was quite as active as the same weight of pure uranium. In order to check these discoveries, she prepared chalcolite artificially, starting with pure products, but found that this artificial chalcolite had only the acti¬ vity represented by its composition, or, roughly, 40 per cent of the activity of uranium. This led to the conclusion that there was some element or substance in the residue from uranium minerals that possesses a high degree of activity. After an exhaustive chemical investigation of pitchblende from Joachimsthal, she found that this mineral contained not only uranium but also another radioactive sub¬ stance, to which she gave the name of polonium, in honor of her native land. Later in 1898, Monsieur and Madame Curie found still another element, which, when brought to a state of concentration, was several million times as active as uranium, and to this was given the name of radium. Debierne afterwards found a fifth radio¬ active substance, actinium; and in 1906 Boltwood isolated the metal ionium. Strict¬ ly pure radium chloride was first produced in 1902. The first radium was produced commercially from the uranium residues obtained from the mines of Joachimsthal, Bohemia. Tyler calls to attention that, as the ores were a government monopoly, search was begun at once for sources in other parts of the world. As a result, radium-containing ores have been found in about 10 countries.

Oct 1, 1932

By Phillip N. Yasnowsky

This Bureau of Mines report summarizes State severance taxes imposed on minerals and mineral fuels, provides a hypothetical example of how a State severance tax affects selected components of a firm's income statement, and uses the Bureau's Minerals Availability System (MAS) to estimate the effect of assumed changes in State severance tax rates on copper recovery cost at given levels of potential copper availability. A reduction of the rates to zero or a doubling of them results in changes in costs that are of the same order of magnitude as the cost of transporting copper to the United States from major foreign producing countries.

Jan 1, 1982

By Philip C. Good

Unweathered low-grade calcareous phosphate rock of about 20 percent P205 grade was beneficiated by a procedure in which contained carbonates were decomposed by calcination at about 1,000° C. On quenching the hot calcined rock in water, major impurities passed into a slime phase which was mechanically separated from a coarser concentrate fraction. Phosphate rock of two major types was beneficiated in batch-scale studies yielding concentrates containing 31.3 to 38.5 percent P205 at recoveries ranging from 54.8 to 86.0 percent. The samples were from two major deposits in India. Processing information gained was utilized in extending the work to a continuous-flow system, processing phosphate rock at rates up to 157 kilograms per hour. Superphosphate exceeding 16 percent water-soluble P205 was prepared from concentrate derived from continuous-flow processing.

Jan 1, 1976

By J. Torma-Krajewski, C. Hipes

Although many mining companies apply ergonomic principles, it is usually done either informally and/or reactively. An example of an informal approach is replacing worn equipment (such as seats) with models that have ergonomic features. Another example is modifying a task to eliminate safety hazards. Such approaches reduce risk-factor exposures that can lead to musculoskeletal disorders (MSDs). A reactive approach is followed when modifying a task/ equipment after an MSD occurs. However, neither of these approaches involves a systematic method of proactively applying ergonomic principles to actually prevent injuries or illnesses. This paper discusses how Vulcan Materials Company applied ergonomic principles and implemented interventions to reduce risk-factor exposures.

By R. S. Dean

In an earlier paper Dean and Hersberger5/ gave preliminary results a d discussed briefly the use in flotation of organic reagents of the type known in the textile industry as "wetting agents.? These reagents are those with a molecular structure comprising a long hydrocarbon chain attached to a. highly molar or hydrophile group in such manner that ionization is nearly complete in dilute solution and the resultant ionic grouping has a very considerable hydrophile-lipophile unbalance in the structure. As a result of this characteristic structure these reagents are more or less powerful frothers and emulsifiers. Ten the degree of bydrophile-lipaphile unbalance is sufficiently great and specific chemical factors are absent these compounds behave in flotation as noncollecting frothers insensitive to reasonable changes of pH.

Jan 1, 1937