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By Ernest W. Johnson

In most underground iron mines in the Lake Superior district the active workings are at considerable depth. When additional openings into such. nines are needed, operating officials are eager to discover more efficient methods of constructing them. In recent years, openings into two mines in the district were made by the borehole method,-which employs chilled-iron shot as the cutting medium. Others were made by the churn-drill method, in which pilot hole is churn-drilled and subsequently reamed to a desired but relatively small diameter. Both methods are comparatively new and unique, at least in some phases and in their application.

Jan 1, 1946

As fulfillment of the requirements of Contract H0387019 for the United States Department of the Interior, Bureau of Mines, a complete field kit, for performing on-site determinations of individual employee Time Weighted Average (TWA) exposures to nitrogen dioxide (NO2) and nitric oxide (NO), has been developed by MDA Scientific, Inc. This report provides background information and experimental data validating the use of this kit with confidence to ? 10 percent accuracy.

Jan 1, 1981

By Donald I. Kurth

The Bureau of Mines conducted experimental work on comminuting coal. The size distributions of coarse fragments and fine particles were obtained under different modes of energy application--drop, impact crushing, wedge impact, compression, and shear tests. Four levels of energy application were used in the impact crushing and wedge impact tests. Airborne dust and respirable air-borne dust distributions were obtained for the impact crushing and wedge impact tests. Analyses of nonairborne dust and coarse fragment-fine particle distributions were carried out on impact, wedge, compression, and shear tests. The experimental size data on nonairborne dust were fitted to normal, log-normal, power law, Weibull, log-Weibull, and exponential distribution functions. Both the nonairborne dust and the coarse fragment-fine particle size distributions are best described by Weibull distributions. For the impact crushing tests, mean product size was found to be inversely related to specific crushing energy. The particle counts in a given size range of airborne and nonairborne dust were found to increase with increased input energy and specific crushing energy. However, in another sense the particle distributions were independent of energy level; that is, the percent-ages in a given size range were approximately constant regardless of energy level. Respirable airborne dust was related to respirable-size nonairborne dust by a power law.

Jan 1, 1975

By A. Navarra, F. Mucciardi, H. Marambio, R. Parra, F. Oyarzún

"Discrete event simulation (DES) is an appropriate framework for the plant-wide analysis of copper smelters. These smelters apply a common set of chemical reactions: copper-iron sulfides are blasted with oxygen-enriched air, sending the iron into a slag phase and the sulfur into the offgas. Moreover, conventional copper smelters exhibit similar operational dynamics: a smelting furnace operates continually, feeding into an alternating set of converters that produce batches of blister copper. The thermochemical and operational commonalities of copper smelters are integrated within the DES framework. This serves as a common basis to begin evaluating the system dynamics of individual smelters. For complex problems, the simulation framework should be developed in phases, incorporating feedback from different personnel who have complementary perspectives. Sample computations are provided in this paper based on the Hernán Videla Lira smelter, whose production is constrained by meteorological conditions. IntroductionWorld copper production is approximately 18.5 million t/y (Brininstool, 2015), worth $80 billion a year. Out of this total, 75 percent comes from the pyrometallurgical processing of sulfide minerals (Fig. 1), which occurs in copper smelters. The remaining 25 percent is from the hydrometallurgical treatment of oxides and complex ores (Rotuska and Chmielewski, 2008), which uses solvent extraction and electrowinning.The current paper describes the pyrometallurgical processing, recognizing that the underlying thermodynamics and kinetics are well known (Degterov and Pelton, 1999), with the notable exception of minor element transport, such as arsenic (As), antimony (Sb), bismuth (Bi), silver (Ag), gold (Au). The latter is an ongoing area of research, as smelters are faced with increasingly complex ores (Devia, Wilkomirsky and Parra, 2012; Swinbourne and Kho, 2012). This paper focuses on the system dynamics of copper smelter operations, which has received considerably less attention than the chemical thermodynamics and kinetics.Smelter engineers and managers may contribute to the sustainability of their plant by improving their understanding of operational system dynamics. Indeed, we have prompted smelter improvement projects (Navarra, 2016; Navarra et al., 2016; Navarra and Mendoza, 2013) simply by adapting methodologies that are commonly used in other sectors. These previous works incorporate principles from computer-integrated manufacturing (Groover, 2000) and theory of constraints (Dettmer, 2007), featuring the use of discrete event simulation (DES)."

Jan 1, 2017

By R. W. Davis

INTRODUCTION CHURCHILL river was named for John Churchill, first Duke of Marl-borough and third Governor of the Hudson's Bay Company, in the latter part of the 17th century, some fifty years after the ill-fated Danish expedition, led by Munck, had abandoned the site of the now famous seaport of Churchill, as a worthless, cold, disease-ridden country. No other attempts were made to explore the interior until the river basin became a part of the grant to the Hudson's Bay Company and began to play its part in furnishing the luxury of fine furs to civilized people as it had furnished the necessities of food and dress for untold centuries to uncivilized natives. This was the sole contribution of the region to the economic life of the country for some two hundred and fifty years, until 1926, when the power site at Island Falls was discovered by engineers seeking a cheap power source to make possible the development of the great ore-body at Flin Flon. DRAINAGE BASIN OF CHURCHILL RIVER The river is some 1,325 miles long. Rising in the headwaters of the Beaver river, in east-central Alberta, it flows in an easterly direction across Saskatchewan and northeasterly across Manitoba to Hudson bay, through a remarkable basin of some 115,500 square miles, only 6,000 square miles less than the area of the British Isles. A journey down this river leads one through three distinct belts of country, each vastly different from the others geologically and in surface characteristics. For the first five hundred miles the river flows through a basin of 36,000 square miles of the great central-plains country, which is covered with fertile soil and carpeted in its southern part with prairie grass, which gradually gives way to the mixed forests of poplar, spruce, birch, and jackpine in the northern and eastern sections: About midway across Saskatchewan, bald-headed knolls and ridges begin to make their appearance as the river meets the western margin of the Canadian Shield. Then, for some seven hundred miles, it passes through country underlain by the pre-Cambrian rocks of the Shield, which continue to within one hundred miles of Hudson bay. Here the character of the country again changes to a low, clay plain underlain by sandstone, and through this 'clay belt' the river flows between steep clay banks, to empty into Hudson bay.

Jan 1, 1935

By J. E. Chilton

Interim performance specifications are presented for carbon monoxide, methane, and air velocity transducers used in the Bureau of Mines intrinsically safe mine monitoring system. These specifications give quantitative values or qualitative descriptions of the transducers, including environmental parameters and monitoring system measurement and maintenance requirements as recommended by the Bureau of Mines. Commercially available transducer modules and prototype modules are listed together with selected characteristics.

Jan 1, 1983

By G. E. McElroy

Changes in existing airway and fan-installation conditions offer the most common opportunities for effecting economical operation of mine ventilating systems, but the largest possibilities for securing this result lie in the original design of the main airways for efficient service. Formulas, and. charts for their graphical solution, are presented herewith for the determination of the elements of airways design when the conditions of service are known, or may be roughly approximated. Although the analyses are made with particular reference to metal-mine airways, there is no essential difference between metal and coal mine main airways, and the methods presented are equally applicable to both. Little attention is paid to designing airways for maximum economy in the ventilation of metal mines. Most of the openings used as main airways are originally designed and used for transportation and other operating purposes. Even where openings are made primarily for ventilation, the possibility of their future use for other operating purposes, or even custom alone, usually results in the selection of a size and shape similar to those of existing openings. Natural conditions, such as heavy ground, often seriously limit the size of opening that can be maintained without excessive expense; and various operating factors, such as velocity limitations on traveling roads, often dictate size requirements in excess of those required for economy in ventilation only. In metal mines the main airways are, as a rule, too small rather than too large for economic service, with the general result that the quantities in circulation are often less than the mine's proper requirements over long periods, even though excessive amounts of power are applied in an effort to remedy conditions.

Jan 1, 1932

By R. E. Heithecker

The separation of enormous quantities of water produced with the oil in some West Texas fields necessitated the use of special equipment other than the regular lease tanks. Several methods were used with varying degrees of success. They include the water-trap, hay tank and gun barrel, gun barrel and settling tank, chemical and electrical-dehydration methods. The water trap which has been used extensively in the Hendricks field, and in some instances has been installed in the Yates field separates the water and. oil under high pressure before tile liquid and gas pass through the flow beam. The first trap was constructed and installed by the Southern Crude Oil Purchasing Co. in July, 1928. By July, 1929, approximately 300 traps were in use. Treating cut oil by running it through a hay tank was done quite extensively in the Roberts-Settles field, Howard and Glasscock Counties, Tex., and later the method was used in the Hendricks field. In July, 1931, there were 37 hay tanks in the Roberts-Settles field, treating the oil from 123 wells. The cut oil frequently was made acceptable to the pipe-line company by running it through the hay tank. In some instances, however, it was necessary to heat the oil, and occasionally both heat and chemicals were used before complete separation of the oil and water was obtained.

Jan 1, 1932

By Robert S. Young

During the last quarter-century, exploration for metallic deposits in Maine has been sporadic with peaks generally coinciding with periods of high metal prices. Known cases of regional or semi-regional evaluations are few; most efforts have been local and usually intensive. On the basis of broad geologic groups, the State has been divided into five fundamental environments: ( 1) coastal metamorphic belt; (2) southern volcanic belt; (3) Silurian slate belt; ( 4) northern volcanic belt; and ( 5) Devonian slate belt. Although not restricted to these areas, exploration in recent years has been concentrated in the northern and southern volcanic belts. Notable examples of recent exploration activity, directed to sulfide minerals, include: ( 1) the Knox County nickel-copper-bearing ultramafic rocks; (2) the Harborside (Cape Rosier) copper-zinc deposit; (3) the Second Pond (Black Hawk) zinc-copper-lead-silver deposit; ( 4) the Big Hill-Barrett lead-zincsilver- copper-gold zones; (5) the Parmachenee copper-zinc belt; ( 6) the Moxie Lake nickeliferous peridotite; and (7) the Attean quartzmonzonite molybdenum-copper occurrences. The Second Pond and Harborside prospects appear to be close to production. Systematic investigations for non-metallic deposits appear to have been aimed principally toward limestone, asbestos, diatomaceous earth, and spodumene-bearing pegmatites. Advances in prospecting methods, high metal prices, a favorable business outlook, increasing cooperation from large landholders, and some discoveries support the probability of increased exploration activity in Maine during the coming decade.

Jan 1, 1968

By F. J. Perzak

The Bureau of Mines conducted a study to develop a standard fire test for 5-gal containers used for storing combustible fluids in underground coal mines. A standard test method was developed which evaluates the performance of the container in a 4-min tray fire. Bureau investigators used the standard test method to evaluate several types of closed 5-gal plastic and metal cans in outdoor tests. Each can tested contained 1 gal of nonfire-resistant (NFR) hydraulic oil. A container failed the test if it lost its contents in any of seven trials. Contents spilled either as a result of thermal rupture or melting. Fewer than 10 pct of the metal containers failed this criterion, but all the plastic containers failed. The metal container failures were usual-ly due to tipping over during pressure relief, which spilled the NFR oil. Replacing the NFR oil in the container with kerosene resulted in failure of more than 30 pct of the metal containers. The standard tests and preliminary tests showed that plastic containers are not equivalent to metal containers in their ability to contain combustibles such as lubricants and greases in a fire. For solvents and lubricants more volatile than NFR hydraulic oil, approved metal safety containers are recommended.

Jan 1, 1985

By Zabetakis M. G.

This Bureau of Mines report presents a brief summary of the explosion trends in United States coal mines for the past 160 years. These trends show that in spite of the overall improvements in mine safety, the number of fatalities from ignitions of methane has actually increased in recent years. Suggestions are made of procedures that can be utilized to reverse this trend.

Jan 1, 1973

By Owen Matthews

Introduction For the past year and a half, the mill of Cochenour Willans Gold Mines, Limited, McKenzie Island, Ontario has been roasting arsenopyrite-gold concentrates, prior to cyanidation, by means of a roaster employing techniques that are new and novel. The roaster is known as the Dorrco 'fluo-solids reactor', and the technique as 'fluidization'. The reactor has demonstrated its ability to roast a flotation concentrate containing arsenopyrite, pyrite, stibnite, small quantities of other sulphides, and some lime silicates and carbonates, yielding a calcine consisting mainly of porous iron oxide, plus the gold values. This calcine is readily amenable to cyanidation. Bulk shipments of concentrates to a distant custom smelter, as practised prior to this installation, has thus been eliminated, with appreciable savings in smelting charges, freight costs, and interest losses during shipment and smelting. This is the pioneer installation of fluo-solids roasting at a Canadian mill and up to the present performance results have not been published. It is the purpose of this paper to present the information now available for the benefit of other millmen who may be confronted with identical or similar problems to those encountered and solved at Cochenour Willans.

Jan 1, 1949

By P. Halsall

Smelters of medium or low grade tin concentrates must recover a high proportion of tin from iron-bearing slags or concentrates; the volatility of tin sulphide makes possible the production of iron-free tin fume. Laboratory work defined conditions which would promote the sulphidisation of tin slags and concentrates melted with them, to result in tin recovery as fume, and a residue of less than 0.5% Sn content, which could be controlled to vary with the value of tin. Subsequently pilot-plant work on 6-tonne and 15-tonne scale led to a commercial plant of 45 tonne. capacity (1962), for melting and fuming primary and secondary low-grade tin materials by submerged combustion. Some factors contributing to the rate of Working expressed in terms of the 'half-life and the amount of work done, the 'half-life-tonne' are studied, leading to the design and operation (1972) of the 100-tonne water-jacketed unit, presently in use, treating a wide range of slags and low tin-content ores and residues.

Jan 1, 1983

By Jinrong (Patrick) Mang

Three of the most challenging problems in phosphate beneficiation are discussed: flotation efficiency, resource conservation and environmental impact. Some new flotation machines offer the opportunity of reducing power and reagent consumption significantly, while increasing specific capacity many fold. Efficiency might also be improved dramatically by replacing the "double float" process with a single-collector scheme. Model based software control is a powerful tool for improving overall plant efficiency. Recovery of phosphate values from the phosphatic clays could extend phosphorus reserve life significantly. phosphate recovery from the slimes might be achieved by sizing-flotation, selective flocculation and bioleaching. Reducing the volume of phosphatic clays produced is another key stop to minimizing phoephate logs. Such a reduction may be realized by floating at finer cut size. Although an ideal' dolomite separation process is yet to be developed, a cationic flotation process may prove to 'be economically feasible. Loss of phosphate in the desliming stage is the major problem with most of the flotation schemes for removing dolomite.

Jan 1, 1995

By R. V. Ramani

"In this paper, the current status of respirable dust control in coal mine atmospheres is presented. The advancements in the engineering control of dust generation and entrainment, and of reducing the exposures are summarized. The results of the Health Surveillance Program are briefly reviewed. The results of research conducted in the Generic Mineral Technology Center for Respirable Dust are presented. The 1995 NIOSH criteria document on respirable coal mine dust is briefly reviewed. The fundamental scientific and engineering issues in need of research are discussed. A detailed bibliography is attached.IntroductionFor coal mines in the United States, the current permissible exposure limit (PEL) of 2mg/m3MRE-equivalent concentration (an 8-hour TWA concentration measured gravimetrically) was established by Public Law 91-173: the Federal Coal Mine Health and Safety of 1969 (the 1969 Coal Act). This standard is reduced when the respirable quartz content in the dust sample exceeds 5%; the reduced standard in mglm3 is obtained by dividing 10 by the percent quartz. The OSHA and ACGIB PEL for respirable coal mine dust is also 2 mg/m3 , and OSHA PEL for respirable quartz is 100 µg/m3 . The 1969 Coal Act also prescribed two activities in the Coal Mine Respirable Dust Sampling Program and the National Coal Workers' Health Surveillance Program n to control respirable dust in mines, and the coal worker's pneumoconiosis (CWP) among the coal miners.There are three principal methods by which personal exposures to respirable dust are controlled. The first is engineering control where the aim is to reduce the concentration in the mine atmosphere to or below the mandated level. The second is the provision of personal protective devices which allow the miner to work in dusty atmospheres without increasing personal exposure. The third is the use of administrative controls where the miner's exposure is controlled through work schedules and procedures to keep miner exposure at or under the mandated levels. The 1969 Coal Act specifically prohibits the use of respirators in lieu of environmental control. The compliance sampling program essentially does not give any credit to the use of administrative controls."

Jan 1, 1998

By W. G. Davenport

Chapter 1 showed that flash smelting is a key step in extracting copper from sulfide ores. It also showed that there , are two versions of flash smelting: (a) Outokumpu flash smelting, which uses oxygen-enriched air blast and injects dry feed downwards into a hot furnace (b) lncoflash? smelting, which uses industrial oxygen blast and injects dry feed horizontally into a hot furnace. This chapter describes Outokumpu flash smelting.

Jan 1, 2001

By Joel M. Modd, Stephen P. Holt

"INTRODUCTION Nickel is one of the seven metals designated as strategic by the Army and Navy Munitions Board in 1939, when Congress appropriated funds for the investigation of domestic sources of supply of war minerals. The Mertic nickel lode at Punter Bay, Admiralty Island, Alaska, owned by the Admiralty Alaska Gold Mining Co., was investigated as part of this program.During the period 1919 to 1928, the property was examined the following engineers; L. S. Robe, W. E. Dunkic and S.E. Conbest of the Alaska Treadwell Cr., A, F. Buddington of the Federal Geological Survey, and H. C. Boydell. Henry M. Eakin, in the capacity of consulting geologist, examined the deposit in 1928 and later reviewed data resulting; from exploration recommended by him. In 1936, A. Hoogbom, of the Geological Survey of Sweden, made a very brief report on the deposit based upon information furnished by J. S. Pokovich.A comprehensive study by the Geological Survey of the Punter Bay area, including the Mertic lode, was made during the field season of 1937, with brief examinations in 1936 and 1938. 4/Miyaki, representing the Mitsubishi Company, visited the property in 1937 and in the course of his examination took six samples. G. W. Powel examined the deposit in 1937 and took five samples in the Mertie adit.This report describes the results of the Bureau's work and gives information collected from other sources."

Nov 1, 1946

By K. C. Dean

During the course of the investigation of manganese mineral occurrences in the western United States, the Bureau of Mines collected several lots of ore' from properties in the vicinity of Winkelman, Ariz. As none of the ores would be marketable directly, an investigation was made to determine their amenability to concentration by ore dressing. The Geronimo group of claims is in Pinal County, 8 miles west of Winkelman, Ariz. The manganese oxides occur as cementing material in ore zones of conglomerate. Representative samples of a 2-ton lot of ore cut from outcrops of two lenticular deposits were laboratory-tested. Two 1-ton samples from the Benningfield property were similar in physical characteristics but differed in grade. This claim is 11-1/2 miles south of Winkelman and about 1 mile west of the San Pedro River on the south side of Putman, Wash. The manganese minerals occurred as nodules and lenses, replacing limestone, in a capping over a dark, igneous dike. The North Star group consists of five claims on the west side of the San Pedro River 14 miles south of Winkelman. The ore consists of a low-grade, manganese oxide-calcite occurrence interspersed with stringers of higher-grade material and is present as filling in a fissure zone in porphyry. Two samples were obtained by the examining engineer; one sample represented run-of-mine material, the other represented ore from the vein that could be hand-sorted or selectively mined.

Jan 1, 1952

By John H. Schilling

The Gabbs magnesite-brucite deposit is unique in size and is one of two magnesite deposits being exploited in the United States. It is near the town of Gabbs, which is one hundred miles southeast of Reno, in west-central Nevada. The brucite was discovered in 1927; the magnesite was found while exploring the brucite. During World War II, more than 80,000 tons of magnesium metal was produced from about 900,000 tons of magnesite ore mined from these deposits. An additional 5,000,000 tons of magnesite and 1,000,000 tons of brucite have been produced for use in making magnesia refractories and chemicals. Basic Inc., presently the only producer, mines 1.5 ± 0.25 million tons of ore and waste annually using high-selective open-pit rriethods; the ore is up-graded, calcined, and processed into a variety of products. Known reserves of highgrade (less than 5 per cent CaO) magnesite ore total more than 25,000,000 tons, and there are larger tonnages of lower-grade material; brucite reserves are small. The magnesite and brucite are in generally west-dipping dolomite of the upper member of the late Triassic Luning Formation, in the over-riding plate of the Paradise thrust fault. A great variety of dikes and a stock of Cretaceous granodiorite intrude the Luning Formation in the vicinity of the magnesite-brucite deposit. The magnesite bodies are scattered over an area of about a square mile around a prong of granodiorite which extends north from the stock. The brucite is mainly in two bodies in contact with the prong of granodiorite; at the surface and along deeper cracks the brucite has weathered to hydromagnesite and artinite. In the area of magnesite-brucite mineralization, much of the dark, fine-grained, schistose, regionally-metamorphosed dolomite of the Luning Formation has been marmorized to a lighter-colored, coarser-grained, massive dolomite that is intergrown in varying proportions with the magnesite. The magnesite and marmorized dolomite can not be distinguished visually. In addition to the two varieties of dolomite, the gangue in the magnesite and brucite bodies mainly is the various varieties of dike rock, serpentine and a variety of other "contact" minerals, and "post-ore" dolomite and calcite. The magnesite ( and recrystallized dolomite) is believed to have formed by the hydrothermal replacement of the regionally metamorphosed sedimentary dolomite; alternatively it has been suggested that the magnesite is sedimentarv and formed contemporaneously with the dolomite in an embayment of the Triassic sea. Because all the igneous rocks exposed in the immediate vicinity of the magnesite deposits appear to be younger than the magnesite, the ore-forming solutions are thought to be related to a somewhat older granite which crops out elsewhere in the area. The brucite is the result of contact-metasomatic replacement of magnesite during the emplacement of the granodiorite stock.

Jan 1, 1968

By N. J. Themelis

The basic chemical, thermal and transport principles that underlie sulfide smelting of. copper, nickel and lead are reviewed. Two basic types of modern smelting processes are distinguished?: flash-smelting, where the predominant reactions occur between oxygen-bearing gas and concentrate particles dispersed therein; and bath-smelting where the concentrate is enveloped and reacted in a turbulent bath of matte, slag and gas. The controlling heat and mass transfer phenomena are discussed, and appropriate correlations are proposed.

Jan 1, 1983