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By Milford L. Skow

This report summarizes the principal activities and results of 15 years of research by the Bureau of Mines, U.S. Department of the Interior, on methane control in coal mines. This research has investigated fundamental factors regarding the occurrence and movement of methane in coal beds, removal of methane prior to mining, and control of methane during mining. The report includes a bibliography listing the more than 150 publications resulting from the Bureau's methane control program as well as numerous other references, a section on methane recovery and use, a look at the upcoming Bureau of Mines research program, and a brief review of methane drainage practices in other coal-producing countries.

Jan 1, 1980

By C. Musingwini

An often overlooked factor in the analysis of mine layouts and schedules is technical operating flexibility (or tactical flexibility), mainly due to its nebulous nature. By glossing over technical operating flexibility the resultant mine layouts and schedules maybe suboptimal. The need to incorporate technical operating flexibility into the analysis and comparison of mine layouts and schedules is increasing in importance. The nature of technical operating flexibility is illustrated, previous work on valuing of operating flexibility reviewed, and a proposal made on how technical operating flexibility can be quantified for tabular reef mines by using a platinum reef deposit as a case study. Once technical operating flexibility has been quantified it becomes possible to explore its incorporation into the analysis of mine layouts and schedules and subsequent optimization processes. This paper is a revised version of a paper presented in the Proceedings of the Second International Platinum Conference, ?Platinum Surges Ahead? in 2006. The work described in this paper is part of a current PhD study at the University of the Witwatersrand. Keywords: mine plans, layouts, schedules, technical operating flexibility/tactical flexibility, ore availability.

Jan 1, 2007

By Rolland L. Blake

The Bureau of Mines is concerned with extracting minerals from residual geothermal brines after their heat content and some demineralized water have been recovered. This literature study is based on a survey of the literature and discussions with individuals knowledgeable on various aspects of the subject. This report examines the potential of the domestic geothermal mineral resources, considers the technical problems involved, and outlines possible effects on the environment from reservoir fluid withdrawal and reinjection. Geothermal resources in the Western United States were extensively explored during the 1960's. Limited development operations included exploratory drilling and operating wells producing hot brine, separating steam for experimental electric power generation, and recovering minerals in solar evaporation ponds or in extraction plants. Interest in the recovery of minerals and salts from geothermal fluids waned because of corrosion and scaling problems and low or no market value of the mineral products. Most of these problems can be controlled with existing technology and careful planning of processes and equipment. Extracting geothermal minerals is technically feasible, but the problems of low or no market value for major mineral products, and insufficient amounts of more valuably major products, make mineral recovery uneconomical at present.

Jan 1, 1974

By M. P. Hay

"For a model to be successful it must address the concerns and needs of a target audience. Further, the model must demonstrate the same patterns of behaviour as the real system, and need only be complex enough to meet this objective. If the model is too complex it can become unusable to those who need it most.With this in mind, SUPASIM has been developed for the practical metallurgist requiring only laboratory flotation rate data as input. Some 35+ successful plant simulations have been completed since 1985. The approach of SUPASIM is to characterise an ore, organise information in an understandable way and add structure to the complex flotation situation and hence support the metallurgist to interpret the relationship between variables and optimise the flotation process.The paper describes the basis on which the model was developed and sets out to provide an insight into interpreting laboratory flotation kinetics and their physical meaning in a production plant and the influence floatable gangue has on float performance and plant design. A case study illustrates how the ratio of slow floating mineral to gangue can influence circuit design and improve recovery on a plant scale.INTRODUCTIONThere is an enormous amount of useful data in the results of a laboratory scale rate test. Each variable of fraction and rate, for mineral, metal and gangue has a physical meaning in the plant. The link between float kinetics and the plant in respect of recovery, grade, pulp density, pulp flowrate, residence time, number of stages of cleaning and circuit configuration has been established by the author in the process of developing SUPASIM."

Jan 1, 2005

By H. C. Brunaugh, James Westfield, R. W. Whittaker

"INTRODUCTION The purpose of this circular is to describe the sealing off of a mine fire and subsequent use of carbon dioxide gas to extinguish it.A fire of electrical origin occurred in the Valier mine of the Valier Coal Co., Valier, Franklin County, I11., on March 29, 1949, at about 1:35 p.m. It was discovered about 3:35 p.m. in 5 south west intake airway inby 1 and 2 west panels. The No. 5 southwest airway had caved, and the fire was in the top coal beneath a large fall of rock. All men, except officials, were ordered from the mine. The mine officials decided to seal the fire, and four temporary seals were erected, which isolated approximately 200 feet of 5 south west entry. The seals were completed on March 30 at 2:45 a.m., but on March 31, at 3;40 a.m,, two of them were blown out by an explosion of gas that was produced by the fire. The two seals were rebuilt, the work being completed on March 31 at 12:00 noon, but they were blown out by another gas explosion at 12:10 a.m. on April 1. It was then decided to extinguish the fire with water if possible.To accomplish this, concrete-block dams were constructed. On April 1, about 4:25 a.m., when the dams were about half completed, water was introduced into the fire area through a 2-inch pipe.On April 4, J. G, Crawford, general manager of the Valier Coal Co., notified James Westfield, chief of the Vincennes (Ind.) Branch, U. S. Bureau of Mines, by telephone of the fire in Valier mine and requested assistance to combat it. Westfield, accompanied by F. J. Smith and H. C. Brumbaugh, Federal coal-mine inspectors, went underground and inspected the seals and dams. Later, during a conference with company officials, it was decided that the concrete-block dams were not strong enough to withstand the hydrostatic pressure that would be produced by flooding the fire area. It was then decided to use carbon dioxide gas to extinguish the fire. Four seals were completed, and 5 tons of carbon dioxide gas was introduced into the fire area, which extinguished the fire."

Apr 1, 1950

By J W. Glatthaar, M Mavotoi

The occurrence of fluorine in the copper/gold concentrates produced by Ok Tedi Mining Limited has provided a series of challenges to metallurgists since 1988. Although fluorine is distributed throughout the gangue minerals contained within Ok Tedi ores, itsÆ presence in talc and phlogopite (naturally floating fluorosilicates) has proven to be the predominate sources of fluorine in the final concentrate. Initial treatment for the fluorosilicates consisted of the use of a carboxy-methyl cellulose depressant added to the flotation cleaners. This was superceded in 1998 with the installation of a fluorine reverse flotation process for the removal of naturally floating fluorosilicates from the final concentrate when the fluorine content of the final concentrate exceeds smelter-defined trigger points. The fluorine reverse process is similar to by-product molybdenite concentrate production in that sodium hydrosulfide is used to depress copper/gold flotation whilst allowing the fluorosilicates to float. The process was installed in two parallel modules (to match the existing grinding/flotation modules at Ok Tedi), each consisting of a closed rougher/cleaner circuit configuration. Both rougher and cleaner cells are Jameson Cells from MIM Process Technologies, with the selection based on both processing characteristics and available construction space. This paper discusses both the nature of fluorine in-, and its removal from-, Ok Tedi copper/gold concentrates.

Jan 1, 2003

By H. M. Chance

Jan 1, 1886

By M. P. Dalton

This paper which describes the milling practice at the Morning concentrator of the Federal Mining and Smelting Co., Mullan, Idaho, is one of a series being prepared by the Bureau of Mines. ACKNOWLEDGMENT The author wishes to acknowledge the assistance given by H. G. Washburn, general manager of the Federal Mining and Smelting Co., and by C. S. Price, assistant mill superintendent, in the preparation of this paper.

Jan 1, 1932

By J. M. Gomes

The Bureau of Mines, as part of an effort to maximize minerals and metals recovery from domestic resources, has investigated the feasibility of recovering heavy minerals as byproducts from sand and gravel, placer gold, and industrial mineral operations in northern California. Sand samples from about 50 locations were treated by gravity separation to yield heavy-mineral concentrates (black sands). Mineral compositions of the concentrates were determined by chemical analysis and mineralogical examination. Individual zircon, ilmenite, magnetite, platinum-group metals, thoria, and silica products were prepared from heavy-mineral concentrates by selective separation using low-and high-intensity magnetic, high-tension, and flotation equipment.

Jan 1, 1979

By R. T. McAndrew

Introduction Drinnan is situated in the Prairie Creek coal area in the Foothills belt of Alberta. It lies on the main line of the Canadian National railway from Edmonton to Jasper. The exact location is shown on the map (Figure I). Interest in the field was aroused by several circumstances: Its proximity to Brule and Pocahontas on the southwest and to Coal-spur on the southeast led to the belief that coal might be economically produced here. There was already at Hinton a 3 ft. 9 in. coal seam being mined by Seabolt. The coal was of very good grade, being black and shiny in appearance with well defined cleavage and a heat value of 12,000 B. t.u. Outcrops of coal had also been noticed on the north side of the Athabaska river and Fish creek. These facts led the Jasper Coal Company to investigate the field. This Company considered taking over the Seabolt property at Hinton, but, owing to the size of the seam, this plan was abandoned and prospecting by diamond drills and test pits was started two years ago in the district east of Hinton. After prospecting had been completed, the most favourable district was found to be in township 51, ranges 24 and 25, west of the 5th meridian. The Company's lease includes all or parts of sections 18, 19, 20, and 28 in range 24, and sections 10, 11, 12, 13, and 14 in range 25. The approximate boundaries of the property are the Canadian National railway on the north, Happy creek on the west, and Cache Percotte creek on the east. The lease comprises 3,100 acres, and the total amount of coal in sight is estimated at 100,000,000 tons.

Jan 1, 1931

By G. L. Oldright

This paper is the first of a series that is to appear on smelting in the lead blast furnace. The objects of this investigation are to determine the conditions obtaining within the blast furnace by direct experimentation, and to correlate the behavior of the furnace at various times with the main factors governing the operation of the blast furnace, and metallurgical losses. ACKNOWLEDGMENTS The writers wish to express their appreciation to the management of the International Smelting Co. at Tooele, Utah, to Mr. J. O. Elton, the general manager, and to Mr. A. B. Young, his assistant, for their broad-gauge policy that has made possible the securing and publishing of these data. For the staff at Tooele, acknowledgments are made to Messrs. B. L. Sackett, general superintendent, Carlos Bardwell, assistant general superintendent, S. Jacobsen, blast-furnace superintendent, H. M. Rockwell, assistant blast furnace superintendent, and J. O. Welsh, superintendent of the general research, for the spirit of cooperation they manifested in carrying out this work. Mr. C. Reish, a member of the research department, was detailed by, the company to assist in this' work and his whole-hearted assistance has been found invaluable.

Jan 1, 1929

By Stephen R. Wilson

The West Tintic mining district is located at the southern end of the Sheeprock Range in Juab County, Utah (fig. 1). Scheelite was discovered in the area during 1940, and the Desert Tungsten Co. began mining in May 1942. The ore was shipped to the Metals Reserve Co. chemical treatment plant at Salt Lake City during the war. A Bureau of Mines development project was established on property controlled by the Desert Tungsten Co. Work was started during September 1942 and completed in February 1943. The program included removal of overburden in the mine area to facilitate geologic napping, followed by surface trenching, diamond drilling, and sampling (figs. 2,. 3, 4, and 5). Eleven diamond-drill holes totaling 1,480 feet were drilled from the surface. Sixty-one samples from the surface trenches and diamond drill holes were assayed. The logs of the holes are given in table 2. Assay results of samples from the surface trenches and diamond drill holes are listed in tables 1 and 3. Geologists of the U.S. Geological Survey mapped the mineralized area during the project period. The scheelite deposits occur in limestone areas adjacent to intrusive m9.sses, which are principally monzonite. The ore bodies are pyrometasomatic in origin, but consist of two somewhat different types: (1) a series of veins occupying fault zones in limestone and (2) tactite bodies immediately adjacent to the limestone. The veins in the limestone have been the most productive of the two types.

Jan 1, 1950

By L J. Strachan, O J. Hawes, S W. Crossen, R C. Roberts

The Albany Conglomerate is a widespread geological unit found in northern areas of Auckland, New Zealand. It has previously been described as part of the early Miocene Waitemata Group which underlies most of Auckland. Much of the Waitemata Group comprises weak interbedded sandstones and mudstones, but also includes conspicuous conglomeratic units such as the Albany Conglomerate. The Albany Conglomerate comprises a well-cemented mixture of hard pebbles, cobbles and boulders of igneous and metamorphic derivation in lenticular beds. A number of tunnelling projects are planned for the near future in Auckland. Recent experience has shown that the variable features associated with the Albany Conglomerate can make selecting appropriate construction methods very challenging. This paper explores the engineering geological and sedimentological features of the Albany Conglomerate with respect to other conglomerates within the Waitemata Group and the potential implications on tunnelling projects in Auckland. Consideration is given to the extent of proposed geotechnical investigations and the production of geotechnical baseline reports.CITATION:Roberts, R C, Hawes, O J, Crossen, S W and Strachan, L J, 2014. Underground construction challenges associated with the Albany Conglomerate in Auckland, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 195–202 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By J. H. McClain

In the last 3 years' operation of the zirconium-production plant, zirconium metal has been employed to good advantage in many applications. The most frequent use has been in situations requiring resistance to attack by hydrochloric acid. In this service, it has been shown to be a serious competitor to Hastelloy. Zirconium also has excellent resistance to most other corrosives end could be considered for use as an all purpose metal. For example, this report cites 18 applications in hydrochloric acid, 4 applications in sulfuric acid, 5 applications in phthalic-hydrochloric acid, 3 applications in wet hydrogen chloride-chlorine atmospheres, and 2 applications in fused caustic.

Jan 1, 1954

By A. G. Roach

HISTORY AND LOCATION SEAL HARBOR GOLD MINES, LIMITED, was incorporated in January, 1934, to take over 116 acres of mining lands in the Stormont gold district, Guysboro county, Nova Scotia. The nearby ten-stamp Mulgrave mill was also purchased, and since that time 974 acres of adjoining properties have been secured from the Government by direct lease. The property is served by a motor road and is about two miles from the village of Goldboro, situated on the shore of Isaac's harbour. The bulk of ?the supplies are brought in by coastal steamer from Halifax, a distance of about 100 miles, since the nearest railway connections are at Antigonish, some 40 miles distant. EARLYY WORK The Seal Harbor properties include the old Partington and Beaver Hat mines. A small tonnage of ore was mined from each and treated on the properties in stamp mills, which were later torn. down . A survey of old records shows that this ore averaged about $8.00 gold per ton. Development work by the present Company was confined to the 100-foot level until February, 1935, but after that rime the incline shaft was deepened to 425 feet and the 300-foot level was explored east and west of the shaft. Six belts of ore were intersected to the west of the shaft. The ore from these belts was hand sorted and the ore portion was put through the 10-stamp Mulgrave mill to defray operating expenses and to serve as a sample of the deposits. The average recovery per ton from this sorted ore was $6.10. Samples of the ore were sent to the testing laboratories of the Mines Branch, at Ottawa, and of Canadian Industries, Limited, at Toronto. Recommendations from both of these authorities were for removal of the coarse gold by concentration and barrel amalgamation, followed by cyanidation of the residue.

Jan 1, 1937

By Isabel C. B Rodrigues, Flávia D. Reis, Versiane A. Leão, Rosa M. F. Lima

Attention has been focused in recent decades upon the precipitation of metal sulphides from acid mine drainage (AMD) and pregnant leach solutions, due to the advantages of the sulphide precipitation process over traditional methods employing hydroxides. The aim of this work was thus to explore technologies for copper precipitation using either Na2S or biogenic sulphide. The recovery of copper sulphide was improved when the initial pH of the solution containing each metal was 4 or excess sulphide was employed. In such, a condition the removal efficiency was 99.9%, corresponding to a residual level of 0.1mg/L for copper in solution. Kinetic parameters for precipitation were determined from the particle size distributions using the method of moments, where the growth and nucleation rates, as well the agglomeration kernel, were calculated. The biogenic sulphide was a suitable alternative to sodium sulphide for copper removal as either sodium sulphide and biogenic sulphide can be utilized to precipitate such a metal allowing the effluent to be compliant with environmental legislation.

Jan 1, 2014

By D. C. McLean

One of the few innovations in hydrometallurgy in recent years has been the utilization of the chemistry of basic iron sulfates called jarosites. These have been used to make iron-zinc separations in the processing of zinc concentrates and are a very important factor in both the Duval and Cymet copper chloride processes as a means of preventing iron build-up in the closed leaching circuits. Copper oxychlorides are kindred compounds in that they are insoluble basic salts that form at low pH (1.5 to 3) and precipitate selectively from many base metal solutions. They have been reported in the chemical literature as far back as 1860, and a few of them are known in their mineralogical forms (particularly atacamite) usually as nuisance minerals because of their chloride content. Several patents describe their synthesis and use as fungicides and insecticides, and papers have discussed their formation as corrosion pro¬ducts on copper and brass piping (14).

Jan 1, 1979

By G. H. Gronhovd

The U.S. Geological Survey estimate of the total remaining reserves of lignite in this country as of Jan. 1, 1967 was about 448 billion tons. This represents 27 percent of the total coal reserves on a tonnage basis and about 17 percent on a thermal basis. Approximately 98 percent of these reserves are in a vast lignite field located in western North Dakota and eastern Montana. This field also extends north into the Canadian province of Saskatchewan. Despite these large reserves and relative ease of mining by stripping operations, lignite production historically has accounted for less than 1 percent of the national total. This is largely due to the fact that the lignite deposits are located in an area that has no large centers of population and the economical radius of transportation is limited by its relatively high moisture and low heating value. Commercial utilization of North Dakota lignite for power production became firmly established in the mid-1920's with the development of the first successful lignite-burning equipment. Most of the early lignite-fired boilers were equipped with spreader stokers, but as the size of the plants increased, pulverized-coal firing became the more popular method, and with few exceptions, the plants built during the past 15 years are pc-fired.

Jan 1, 1968

By E Cunha, D Roldao, TáTamantini, J F. C L Costa, T Webber, C Monteiro

The main problem of geostatistical simulations is to reproduce the real characteristics of the mineral deposit when there are few conditioning data. In this case, the geological interpretation, based on structures, geophysics and geological maps, plays the major role in terms of resource evaluation.The paper investigates the use of principal component analysis (PCA) to help classify multiple geostatistical categorical simulations considering the similarity among them and the interpreted model, herein referred as training image (TI).An iron deposit with four lithological facies, in a specific horizontal plane, was used as case study for two-dimensional (2D) simulations. Sequential indicator simulations (SIS) was used to obtain ten equally probable 2D images, which were generated and compared against the interpreted model (TI).In this study, 11 random variables are comprised by the vector of ten SIS realisations plus the training image (TI). The similarity between the TI and each SIS realisation is measured using the angle between the TI and SIS vectors projected in the new coordinate systems (PCA factors). It is possible to order the SIS realisations from the highest to the lowest PCA factor taking into account the TI similarity.The visual analysis of the images shows coherence in the PCA results as a method to measure similarity. This methodology can be used as a post-processing tool to rank simulation results and to select the ones which better represent the prior known geology or to compare the quality of different methods of simulation.

Sep 26, 2011

By Brad Simser

Several case histories from Glencore’s Sudbury Operations show how passive seismic monitoring data is used for geotechnical decision making. The data comes from three different seismic arrays monitoring two open stoping deposits, and a narrow vein cut and fill/blasthole operation. Mining depths range between 1000 to 1680m below surface. The deposits are hosted in hard igneous rocks typical of the Sudbury basin, with characteristically high horizontal stress (approximately 1.8 times the depth of overburden). Rockbursting is the main geotechnical risk, due to the strong brittle nature of the rock and local high mining extraction. Fault related seismicity includes both fault slip events, and the stress channelling effect as the mining front approaches a major fault structure. Planar data trends generally line up with known faults and often indicate early stage fault activation. The structures are risk ranked based on their seismic response. This has been particularly useful at the Nickel Rim South Mine (NRS) where the structural fabric (jointing and small-scale faulting) is generally parallel to the more through going faults. The persistence of structures is difficult to measure, and the NRS faults generally have low offsets and thin gouge. The visual difference between the more persistent structures that occasionally generate large seismic events (up Mw 2.9 to date) and localised joints/slips is often minor. The seismic monitoring data clearly shows the more active structures. This information is highlighted on mine plans to help guide enhanced ground support and seismic re-entry protocol barricade locations. Pillar loading/yielding is a key element to the blasthole operations where a primary/secondary mining sequence is used. The secondary pillars are mined in a yielded state with just-in-time development. An example of the seismic signature of a secondary stope is shown with emphasis on the need for high location accuracy given the stope widths of 12.5 to 15m. The ratio of the shear wave energy to primary wave energy (Es/Ep) has long been used as a method to estimate source mechanisms; the higher the ratio, the more likely the event is fault slip versus rock fracturing. Data sets are filtered on Es/Ep ratios to highlight both fault slip populations and stress fracturing mechanisms. Examples of seismic data quality checks, high stress development, and re-entry protocols are also shown in the case histories.

Apr 26, 2022