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By Harold F. Yde

Hydraulic tailings fill in the Butte deep level mines was based upon studies made in 1958 by the Anaconda Company Mining Research Department, which published Bulletin No. 35, entitled "Hydraulic Stope Filling". Since then, many things have changed. At the time of the Research Departments study, dry mine tailings were hauled by rail cars from the Anaconda tailings ponds, twenty-five miles distant, to the underground mines' tailings fill plants at the Leonard Anselmo, and Mt. Con Mines. Now, with the installation of the new Weed Concentrator in Butte, tailings is delivered by pipeline to a cyclone at the Kelley Shaft, and stope filling has become more highly automated and streamlined. Presently, mill tailings at approximately thirty percent solids by weight, is pumped from the concentrator, eight thousand feet horizontally and upward, to the Kelley Fill Plant, where they are dewatered and deslimed by three Krebs Model D20B Cyclones, which discharge the material into the cased and grouted mine delivery bore holes at desired densities up to seventy percent solids. The vertical boreholes and four-inch rubber lined Victaulic pipe carry the material downward to horizontal distribution lines, which in turn tap into the stops-filling, three inch, unlined steel Victaulic pipelines. The slurry may travel several thousand feet before it finally discharges into the stope, where it lends support to the mined-out area.

Jan 1, 1969

By J. M. Belland

This paper deals with the geology of the Smallwood mine in relation to its influence on mining and milling operations. Structure within the orebody, and variations in ore grade and material types, will be described and associated with the various drilling, blasting and milling operations. The orientation of planes of weakness, either bedding or jointing planes, and contacts between extremes in material types influence the size of the broken material. Generally speaking, variations in grinding rates and recovery can be associated with stratigraphic sequence and metamorphism.

Jan 1, 1966

By Joseph Gersic

In 1989-90, the Bureau of Mines appraised selected high resource potential areas containing gold, rare-earth-element, or pegmatite deposits in or near the Black Hills National Forest. Available mineral resource data were used to construct mine and mill models and to compute discounted cash-flow rate-of-return analyses. Using this information, the economic feasibility of possible operations and probability (in the nonmathematical sense) of exploration and development within the next decade were assessed. High exploration and development probabilities are forecast for gold deposits around existing and permitted mine areas near Lead-Deadwood and west of Galena. The area east of Galena has low to moderate exploration and development probability; the Rochford area has low to high exploration probability and low to moderate development probability; the Keystone area has low to moderate exploration probability and low development probability; the Medicine Mountain area has moderate to high exploration and low to moderate development probabilities. Exploration probability in the Bear Lodge Mountains area is high for rare-earth elements and gold; development probability is low. Exploration probability for gold in the Mineral Hill area is low to moderate; development probability is low. The current level of activity associated with pegmatite mining in the Black Hills would probably not change significantly in the next decade; both exploration and development probabilities are low to moderate.

Jan 1, 1990

By R. J. Lee

Asbestos analysis is conceptually simple. The objective, in most environmental analyses, is to determine the number of asbestos fibers per unit area or volume in a sample. The sample may be a consumer product, an ambient air sample, or a water sample. This determination is complicated by several factors including sample collection and preparation, counting techniques, and the operational definition of asbestos in use. Three different definitions have been used in the study of environmental samples; these are summarized in Table 1. [ ]

Jan 1, 1979

By P. J. Colbassani

Samples of mine atmospheres collected by Federal coal-mine inspectors during their inspections and investigations of coal mines, in accordance with provisions of the Federal Coal Mine Safety Act (66 Stat. 692; 30 U. S. C., sees. 451-483) are analyzed routinely by chemical methods at Bureau of Mines laboratories. When samples collected in open workings of nongassy coal mines at points not less than 12 inches from the roof, face, or rib contain 0.25 percent or more methane, the act requires the operator, during operation of such mine, to comply with the provisions of sec. 209, Title II, of the act, which pertain to gassy mines. The methane con-tents of such samples are determined by a physical method based on infrared absorption spectrometry to provide an independent check on analytical results obtained by chemical methods. This information circular describes the equipment and procedures used by the Bureau for determining low concentrations of methane in coal mine atmospheres by infrared absorption spectrometry. ACKNOWLEDGMENTS The authors are indebted to Dr. R. A. Friedel, Chief of Spectrometric Section, Branch of Coal-to-Oil Research, Bureau of Mines, for suggesting the analytical method and for furnishing valuable advice and assistance, and to J. A. Queiser of his staff for making exploratory measurements by this method; to Dr. M. G. Zabetakis of the Division of Explosives Technology for his assistance during the conduct of preliminary experimentation; and to L. B. Berger, Chief, Branch of Health Research, under whose guidance the equipment was procured and the work conducted.

Jan 1, 1958

By Balmer Neilly

We are regularly told that before making a new investment one should seek the advice of his banker. If we were to place the subject matter of this paper before bankers. other than those who have experience in our mining camps, their reply would probably be evasive. However, if for example: a mining company asks them for a loan and offers as security certain mining investments, they are, in most cases, explosively candid. The idea is preposterous, unless, under Section 88 of the Bank Act, the mining company is able to deposit with the bank, gold or silver bullion, to an amount sufficiently in excess of the loan, to provide for what the banker describes as a reasonable margin of safety in case of contingencies. In addition the directors of the mine personally must jointly and severally guarantee payment of the loan. With any of these conditions missing the banking atmosphere becomes chilly. The local manager explains that the general situation, and particularly European conditions, are so unsettled that head office has warned him that his discretionary powers must not be exceeded under any circumstances.

Jan 1, 1924

By Nic Arrieta

The Arimetco White Cliff Diatomite operation near Tucson, Arizona will be discussed and reviewed across the spectrum of geology, mineralogy, mining, processing and product attributes and market applications. Unique for the operation are the type, quality and the extent of the reserves and several product characteristics of the diatomite.

Jan 1, 1996

By John J. Barakso

A summary of geochemical dispersion processes is presented. Secondary and tertiary dispersion of uranium was examined at several uranium prospects in British Columbia. The vertical migration of uranium from bedrock (primary dispersion) through overburden into the various soil horizons, and into snow and plants, was studied, and relationships were sought to explain the dispersion patterns in the secondary and tertiary environments. Soil developments were examined to obtain information on factors affecting the dispersion of uranium in soil profiles and tertiary substances; samples were analyzed for a number of elements. Biogeochemical data indicate that plant geochemistry is a possible exploration aid in areas of heavy overburden owing to the high selectivity of certain plants for specific elements. Some new data on the geochemistry of snow are discussed as a matter of research interest in the tertiary dispersion of uranium. Analytical techniques and problems are discussed, particularly extraction techniques, which must be carefully chosen to give reliable information on uranium dispersion.

Jan 1, 1979

By Paul H. Atkinson

"Sampling in the mineral processing industry has always been a subject which has received considerable discussion. There have been many volumes written on theory, techniques and practical application of sampling. However, until recently, the companies were not completely aware of the potential savings available with properly designed sampling systems both to assist in pieces: control and final product values.Definition In our discussion today, we will define sampling as the operation of removing a part, convenient in quantity for analysis, from a whole, which is of much greater hulk, and removing it in such a way that the proportion and distribution of the quality to be tested, i.e. size of particle, moisture content, specific gravity content, mineral and chemical composition, are the same in both the sample and the whole.Application It has been well established that undetected errors can result in large economic losses, thus most firms depend upon some type of sampling and sample analysis as a control in their continuous processing of materials. Despite the large investment in facilities and personnel the ""analysis"" of a sample can be no more accurate or reliable than the sample on which it is being based. The importance of sampling is recognized by a great many but it is appreciated by only a few, largely because it is sometimes one of the items which is taken for granted."

Jan 1, 1976

By R Lau

The fire safety design for road tunnels includes the following aspects: active systems, passive provisions and operational procedures. The active systems include the smoke control system, fire suppression system, detection system and fire fighter’s assistance systems. Passive provisions include escape passages, fire separation and fire resistance systems. The operational procedures refer to fire fighter access, reporting and alerts, evacuation processes and crowd control.Currently, these systems are typically designed by different designers or teams. These systems are intended to work together in a coordinated manner to provide the desired safety outcome. However, in practice, this is not always happening. The fire engineering process is supposed to bring together all these aspects and arrive at an integrated safety system. The fi re engineering process in practice is not integrating the design with the practice or reality and is thus arriving at less than desirably efficient safety systems.The example of design inputs shows how disconnected each system design basis is. The smoke control system design is based on the design fire size. The performance of the smoke control system is to achieve a smoke free environment for a defined space for a particular fire size – the design fire. The fire suppression system – most commonly sprinklers or deluge systems, is designed according to codes and to achieve a certain water discharge rate. The fire detection system is designed to detect temperature rise/rate of rise and perhaps density of smoke. Fire separation is determined to provide a certain period of service – mostly for structural elements. Escape route size and location is determined mostly by code compliance. Evacuation procedures are determined by Authority operational requirements rather than human behaviour.To arrive at an integrated fire safety system, the design basis and performances must be coordinated. An approach using fire scenarios would ensure all systems are designed to a common performance requirement. This paper will discuss how the current design approach outcomes compared with a fire scenario approach. More effective and efficient fire safety systems would require the stake holders to understand the implication of this approach and to embrace this through the fire engineering process.

Mar 8, 2011

In parallel work, the cyanide/silver impregnated activated carbon system was studied for the purpose of developing an alternate cyanide removal system. It was found that free cyanide can be reduced from 20 ppm to below 10 ppb with a fixed bed of silver impregnated activated carbon, since such cyanide removal might be applicable to gold mill effluents, the investigation was extended to the cyanide/gold impregnated activated carbon (GIAC) system. Batch tests were conducted varying the gold content of activated carbon, carbon/CN ratio, stirring speed, pH of the initial solution, and the reaction temperature. The adsorption isotherm of cyanide/gold impregnated activated carbon system was also studied. The results of these batch tests show that the behaviour of the cyanide/GIAC system is very similar to the cyanide/silver impregnated activated carbon system variation of the gold content of the impregnated activated carbon has some influence on the cyanide adsorption rate. The latter is mainly increased, however, by increasing the GIAC/CN ratio. The activation energy was determined to be 3.12 kca1/mole (13.08 kj/mole) and the Au(CN)2 saturation at 194 µ M/g NORIT ROX O.B. The experimental results of reaction temperature and stirring speed show that the adsorption of free cyanide on such activated carbon is controlled by pore diffusion inside the activated carbon particle or by surface reaction. The adsorption isotherm follows the linear model and it is favourable for the cyanide/gold impregnated activated carbon system.

Jan 1, 1994

By Harry V. Makar

As part of a continuing research program for conserving domestic mineral resources, the Bureau of Mines is investigating new and improved scrap identification techniques to improve sorted mixed scrap purity. This report focuses on various classes of wrought and cast copper alloys produced with recycled scrap. Based on a survey of the literature, principal alloys, such as the brasses and bronzes, are examined with respect to impurity elements and their effects on metallurgical behavior. Effects of elements such as lead, antimony, iron, chromium, and aluminum are discussed. The metallurgical effects described include hot shortness, fire cracking, and undesirable phase transformations.

Jan 1, 1985

By A. D. Garman

This paper presents one of a series of digests of foreign mining legisla- tion and court, decisions which is being prepared in advance of a general report relative to the right of American citizens to explore for minerals and to own and operate mines in various foreign countries. This interpretation of the laws of Latin America has been prepared from the best available information in Washington, but is released subject to correction and amplification, if necessary, by the proper American diplomatic and consular officers, to whom it is being referred through the courtesy of the Department of State. Individual abstracts of the laws of each of the countries herein discussed have been prepared and published separately. This general summary is presented for the use of mining engineers and investors whose interests extend over the borders of a single country. It is also designed to bring out certain general principles of mining law and, so far as feasible, to indicate the trend of mining legislation in South and Central America. In order to gain perspective, the details of legislation are not com- pletely covered in this paper, but an effort has been made to bring out essential differences as well as points of similarity in the laws of the various countries. The course of legislation is first traced chronologically and the points discussed are then arranged in tables in somerhat greater detail. .Si. With a very few exceptions the existing mining legislation of Spanish America is a development, of the Spanish "Law Decree of Bases" (more briefly referr- ed to as the "Decree-Bases") of 1868. This in turn was influenced, particularly in its classification of minerals, by the French law of April 21, 1810.

Jul 1, 1930

By W. W. Scott

Measurements of the absolute value of electromagnetic noise and attenuation along a hoist rope were made in an operating hard-rock mine, Lucky Friday Mine, located near Wallace, Idaho. Spectra of electromagnetic noise generated by various pieces of equipment, spectra of specific noise signals at various depths, and noise and attenuation on the 4250 foot (1295 meter) hoist, were measured. Three techniques were used to make the measurements. First, noise was measured over the entire electromagnetic spectrum of interest for brief time periods. Data were recorded using broadband analog magnetic tape for later transformation to spectral plots. Second, noise amplitudes were recorded at several discrete frequencies for a sufficient amount of time to provide data for amplitude probability distributions. A third technique gave attenuation data through the direct measurement of field strength at various depths. The specific measured results are given in a number of spectral plots, amplitude probability distribution plots and amplitude curves as a function of depth.

Jan 1, 1974

The inquiry into the explosion at the Moura No. 2 Mine in August 1994 recommended -?Emergency procedures should be exercised at each mine on a systematic basis, the minimum requirement being on an annual basis for each mine.? (Windridge et al. 1996). In December 1996 the ?Approved Standard for the Conduct of Emergency Procedures Exercises? was published and has been subsequently revised (Queensland Department of Mines and Energy Safety and Health Division 1999). This document provided guidelines for conducting mine site emergency exercises as well as the requirement for a test of state-wide emergency response by holding a Level 1 Mine Emergency Exercise at one mine on an annual basis. From 1998 to date (January 2008) ten Level 1 Mine Emergency Exercises have been held in Queensland, Australia. This paper discusses each of the exercises conducted to date as well as the logistics, scenario preparation, planning and organising required to conduct emergency exercises at this level.

Jan 1, 2009

By Don Langlois, Udo Weber

"The effect of grinding media performance on milling and operational behaviour was demonstrated under different selected milling conditions of calcium carbonate. A variety of grinding media material and bead sizes, along with 2 different stirrer tip speeds, were used in the grinding process to generate a particle size reduction of the calcium carbonate (CaCO3). To determine the optimum milling parameters the collected test data was used to calculate and evaluate specific energy as well as stress intensity under different milling conditions.INTRODUCTIONAs a result of increasing energy costs and raw material prices it is important to look at the efficiency of the manufacturing process. Wet grinding and ultrafine wet grinding in stirred media mills are now a possible cost-effective production step for the processing of industrial minerals and precious metals. The generation of smaller particle sizes (down to micrometer scale) can be advantageous for further production steps – i.e. better liberation of precious metals or improved industrial mineral qualities.In the following, the wet grinding process is investigated under different milling conditions of calcium carbonate. Different grinding media materials varying in specific weight, bead size and stirrer tip speeds are used to determine optimal energy consumption for the milling process.DESCRIPTION OF TEST CONDITIONS AND PARAMETERSMill ParametersTests were performed in a Drais Laboratory Perl Mill PML H/V with an installed electrical motor power of 3 kW. The mill chamber is silicon carbide where as the stirrer and discs are made of yttria stabilised zirconia. The mill working volume is 0.9 l. A screen cartridge with a screen size of 0.2 mm is used to separate the beads and slurry at the outlet of the mill. All tests were performed with a grinding media filling grade of 80% (Mill working volume). The stirrer tip speed was set at 6 m/s and 10 m/s."

Jan 1, 2009

By R. A. Friedel

THE UTILIZATION by the Bureau of Mines of infrared and ultraviolet-visible spectrometry in connection with coal research has led to some basic improvements in methods, including a calibration method, a quantitative assessment of infrared spectral energy sources, and the development and perfection of infrared filters and cells. The adoption of a micropipet method to flush organic samples into absorption cells permits the investigation of vapors from organic liquids and the identification of volatile organic compounds. The spectral method has been used to investigate the infrared spectra of metal chelates, the charge-transfer complexing properties of aniline and nitrobenzene, an infrared method for determining the presence of methane in coal-mine air that has been adopted for use in enforcing the regulations of the National Coal Mine Safety Act, and atmospheric pollution including smog and odor-causing oxidation and decomposition of organic materials. Correlation of spectra and structure of organic compounds, particularly aromatics, was studied.

Jan 1, 1966

By R. G. K. Morrison

As mines grow deeper, the problem of ground control becomes one of increasing importance. The literature on the subject has grown extensively in the past few years, but is still far from conclusive. Detailed and precise observations are on record covering most phases of the problem, and control measures have progressed to the point where, in a large measure, they are effective. The success of methods to date must be attributed to the efforts which have been exerted to reduce convergence of stope walls and to the realization that a regular progression of stope faces approaching longwall has a beneficial effect. This paper attempts to explain the relationship between these two factors and the general problem of ground control. The problem at present lacks the co-ordination of the practical with the scientific outlook, but fortunately as time goes on there are indications that our scientific friends are becoming more interested and more familiar with the practical issues involved. Opinions vary widely regarding the mechanism of the problem and there are several schools of thought, two only of which will be discussed. One associates the incidence of rock-bursts with the stresses built up by a sagging hanging-wall, while the other takes the view that stresses primarily responsible for the sagging hanging-wall are also the cause of rock-bursts. The first group starts its reasoning from the convergence of the walls, probably the most conspicuous feature of deep mining, and works back to the conclusion that rock-bursts are in sorne way due to the breaking up of the sagging layers. The second group begins with the stress zone apparent around excavations at depth and follows mathematical conceptions based on certain assumptions which, in the absolute sense, are known to be inaccurate, but which are justified by the similarity between the conclusions reached and the results obtained in practice. This reasoning is followed to the point where rock-bursts result from the failure, under stress, of rock in situ, quite independent of wall convergence.

Jan 1, 1939

By J. A. Marts, R. C. Gilmore, Jr. Bogin, S. A. Saki, J. F. Brune, J. W. Grubb

"Colorado School of MinesResearchers at Colorado School of Mines (CSM) have developed computational fluid dynamic (CFD) models to study gas distributions and explosion and fire hazards in longwall gobs. In underground coal mines, methane continuously emitted from surrounding strata mixes with air from active mine workings and may form explosive gas zones (EGZs). Some western United States coal mines are also prone to spontaneous combustion (spon com). Insight into oxygen concentrations within the gob is crucial for assessing spon com hazards and mitigation strategies. Nitrogen injection used in conjunction with progressive gob sealing can reduce EGZs and spon com hazards by forming a dynamic seal that separates the methane in the gob from the air that ingresses from the face. This paper describes CFD modeling simulations studying the formation of such dynamic seals by optimizing the nitrogen injection locations. The impact of nitrogen on oxygen ingress and formation of EGZs is discussed. Optimum nitrogen injection quantities and injection locations were determined. Dynamic seal formation is most effective if the headgate nitrogen injection locations are split between the first crosscut inby the face and a second location about 300 m (1,000 ft) further inby. INTRODUCTION Underground longwall coal mine ventilation systems are designed to dilute hazardous gases and to provide breathable air to miners working in the area. Methane gas is liberated as the mining process extracts the coal and disturbs the surrounding strata. Methane mixes with the ventilation air and often produces explosive gas zones (EGZs) within longwall gobs (Brune 2013). Past CFD modeling research of underground coal mine ventilation systems has shown the effects of face air quantity on EGZs (Worrall 2012) and nitrogen injection to control spon com (Balusu et al. 2005; Ren et al. 2012; Ren et al. 2011; Smith and Yuan, 2008; Yuan and Smith, 2014). Other modeling approaches include network ventilation models of oxygen ingress (Dziurzynski and Wasilewski, 2012), and coupled Linear Network CFD algorithms (Wedding 2014). In a project sponsored by the National Institute for Occupational Safety and Health (NIOSH), CSM researchers are using Fluent®, a CFD software package by ANSYS, Inc., to model gas compositions and flows in underground longwall gobs. Figure 1 shows a progressively sealed gob with a U-type ventilation system in a three entry development. As the longwall advances, seals are constructed along the headgate in the crosscuts between the center entry and the gob. Additional gob isolation seals are built to block off the headgate entries inby the face. Nitrogen is injected through the seals in the first two crosscuts on the headgate side and at the first crosscut inby the face on the tailgate side, as shown in Figure 1."

Jan 1, 2015

By N. Chow, W. McCombe, G. Remple, J. Nikkari, L. Nightingale-Mercer

Orano Canada Inc. (Orano) operates the McClean Lake mill in northern Saskatchewan, processing high concentration uranium ore, delivered in slurry form, from the Cameco operated Cigar Lake mine. This slurry is ultimately processed into the purified uranium oxide product known as calcined yellowcake. During the calcining process, sulphate (SO42-) entrained in the yellowcake undergoes thermal decomposition into sulphur dioxide (SO2). SO2 is a colourless gas that poses health and safety risks. Since 2016, an anhydrous ammonia dosing system was successfully added to the existing Venturi particulate scrubber system to provide efficient removal of SO2 from the calciner off-gas. Within the pH controlled scrubber solution, SO2 exists in a pH dependent equilibrium with sulphite/bisulphite (SO32-/ HSO3-). The presence of a significant fraction of reduced sulphite and bisulphite in mill solutions presents a hazard in downstream circuits. Should these solutions drop in pH, either through natural oxidation or inadvertent mixing with low pH solutions, the solution equilibrium will shift from SO32-/HSO3- in favour of SO2, resulting in the evolution of SO2 gas from any liquid surfaces. In 2018, Hatch Ltd. (Hatch) and Orano implemented a design change in the calciner scrubber system. Blowdown from this system is now treated in an oxidation pre-step utilizing hydrogen peroxide (H2O2) and anhydrous ammonia (NH3) for pH control, in order to convert the residual sulphite/bisulphite present in solution to stable ammonium sulphate product. This paper will detail some of the challenges and actions undertaken to minimize SO2 risk, culminating in the recent introduction of a novel system designed to oxidize sulphite/bisulphite and prevent mobilization from the calciner scrubber solution into other mill areas where there is the potential for acidification and SO2 release.

Jan 1, 2020