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By Xiaoping Xu

An albitization granite type tantalum-niobium ore from Jiangxi Province, China was taken as the research object in this paper. The main valuable minerals in this ore are tantalite-columbite and uranmicrolite, and the minerals that can be comprehensively recovered include cassiterite, sulfide minerals, topaz, zinnwaldite, and quartz-feldspar. Based on the research results of process mineralogy, the roughing process of gravity separation for coarse particles combined with flotation for fine particles is proposed. The combined cleaning process of flotation-gravity-magnetic-electric-hydrometallurgical separation is adopted for the rough concentrate of gravity separation while the combined cleaning process of gravity-flotation- hydrometallurgical separation is adopted for the rough concentrate of flotation. High intensity magnetic separation is used to separate and recover zinnwaldite and quartz-feldspar from gravity tailings. By mineral processing for the crude ore containing (TaNb)cassiterite concentrate is 0.0003% with a grade of Sn 63.22% and a recovery of Sn 47.42% while the yield of sulfide concentrate is 0.0783% with a grade of Pb 33.15% and Zn 27.09% which can be separated to get lead and zinc concentrate respectively. The yield of topaz concentrate is 0.1545% and the topaz mainly distributed in the size range of -0.4+0.074mm, which can be made into abrasive products of different particle sizes after classification. The yield of zinnwaldite concentrate is 16.91% with a grade of Liwhiteness of 75%, which is a glass-ceramic material of good quality. 2O5 0.0346%, Sn 0.04%, Pb 0.10% and Zn 0.33%, the tantalum-niobium concentrate with a yield of 0.00278%,a grade of (TaNb)2O5 53.61% and a recovery of (TaNb)2O5 44.49% is obtained. And the yield of 2O 1.34% and Rb2O 0.40%. The yield of quartz-feldspar concentrate is 30.42% with a grade of K2O+Na2O 8.98% and Fe2O3 0.11% and a natural All of tantalum, niobium, cassiterite, topaz, zinnwaldite, quartz, and feldspar are recovered effectively. Keywords: tantalum-niobium ore, gravity separation for coarse particles, flotation for fine particles, comprehensive recovery

Sep 1, 2012

By M. Ge

An in-seam seismic (ISS) - based void detection technique was developed and tested for three general mine conditions: anthracite, bituminous and trona. The detection range tested varied from 80 to 100 m for trona mines and from 33 to 66 m for bituminous mines. High quality and broad band signals were obtained from these tests and were used to delineate the voids. The paper provides a brief discussion on the technical features of this void detection technique, the testing conditions and results, and a general assessment of the technique.

Jan 1, 2010

"The Ohio River Bridge East End Crossing Tunnel requires a 75-year service life of its cast-in-place reinforced concrete lining. This twin-tube 3-lane (each tube) highway tunnel is about 55-ft wide and 30-ft high. Since unified tunnel service life prediction methodology does not exist in the US, challenges occurred during the design-build phase of this project. These challenges include the methodologies in determining the reinforced concrete’s degradation mode, the lining’s surface chloride concentration level, the reinforcing steel’s critical chloride threshold value for corrosion, how to verify the concrete’s diffusion coefficient, and the durability impact from concrete crack width. This paper presents a methodology in verifying the proposed concrete mix can achieve the service life requirements. This methodology can be adopted for service life prediction for future tunnels to be built in the US. INTRODUCTION The Ohio River Bridge East End Crossing (ORBEE) Tunnel is part of a Public Private Partnership project, which connects transportation network between Louisville, Kentucky and southern Indiana. Located in Louisville, Kentucky, the twin-tube highway tunnel provides northbound and southbound lanes of the Kentucky approach to a new bridge across the Ohio River. Tunnel lengths are approximately 1,675-ft and 1,685 for the northbound tube and the southbound tube, respectively. Connected by two cross-passages, both tubes have a roadway width of 40-ft, for 3-lane traffic, and a vertical clearance of 26.5-ft.The tunnel was constructed by drill and blast method with shotcrete and rock dowels as initial ground supports. The final tunnel lining system includes: •,Nominal 16” cast-in-place reinforced concrete lining, with 2” and 3” concrete covers over reinforcing steel for its extrados and intrados, respectively. •,20” cast-in-place reinforced concrete invert slab, with 4” and 3” concrete covers over reinforcing steel on its top face and bottom face, respectively. •,PVC waterproofing system around tunnel perimeter, excluding invert slab. •,Perforated PVC groundwater collection pipes on both sides of the tubes and one below the invert slab of each tube."

Jan 1, 2016

By R R. Wainwright

Friction-type hoists have been in operation at Geco Mines Limited since Septtember, 1957. At the end of the year 1963, the skip hoist had handled nearly ~ million tons of ore and waste. In March, 1962, with the deepening of the shaft, the hoisting de11th was increased from 1,450 to 2,450 feet. Operating experience with the hoists, hoist and balance ropes, rope treads and other related equipment is presented. The paper is intended to supplement an earlier one -"Heavy-Duty Friction Hoisting at Geco Mines," by W. M. Harvey (C.I.M. Transactions, Volume LXIII, 1960, pp. 193 -197). General G ECO Mine Limited is located at Manitouwadge, Ontario, approximately 160 miles east of Port Arthur and 190 mile northwest of Sault Ste. Marie. The Company was formed to exploit a copper-zinc-silver orebody, with current ore reserve (1963) of approximately 21 million tons. The production plant was designed to mine and treat 1.25 million tons per annum. The production and service hoists are mounted at-the top of a reinforced concrete tower above the shaft.

Jan 1, 1965

By C. O. Swanson

"OUR INTEREST in estimates of world reserves of lead and zinc is focussed mainly on the information they give about the sufficiency of metal supplies for the future. However, we soon realize that the estimates can be interpreted in several different ways. Accordingly, it is necessary to have some under-standing of the elements represented by a compilation of world re-serves, and we will start by examining the accuracy of the estimates and what they attempt to measure.Variations in Estimates of the ReservesIf we study the estimates of world reserves that have been published in recent years, we note immenediately that they vary over a considerable range. For example, an article by Shea in 1947 gave world reserves as about 36 million tons of lead and 60 million tons of zinc. Shea did not in elude the United States but I have added to his totals the estimates made by the Bureau of Mines for that country in arriving at the foregoing figures. For approximately the same date, the American Zinc Institute and the Lead Industries Association reported world reserves as about 50 million tons of lead and 77 million tons of zinc. A comparison of the two sets of figures shows a mean variation of 30 per cent. For individual countries the difference between estimates can be even larger. A few years ago the estimate of Canada's reserves made by the United States Bureau of Mines was 7.4 million tons of lead and 14.0 million tons of zinc, while the Gordon Commission reported 1 O. 7 million tons of lead and 26.0 mil-lion tons of zinc. In this case the mean variation was 55 per cent."

Jan 1, 1960

By C. W. Davis

Before listing the laboratories and the work performed there, it is proper to make clear what is done and what is not done by Federal bureaus, States, and Territories, as well as by countries to the north and south of the United States. FEDERAL Bureau of Mines. - The Bureau of Mines does not make assays or analyses for individuals or firms unless the samples are part of the ore-testing and ore-dressing investigations of the Metallurgical Division on representative ores from mining districts and of possible benefit to the entire mineral industry through published reports. All significant results obtained in this way are made public. Any mineral sample sent to this Bureau for simple identification will be examined.

Jan 1, 1938

By T. V. Ramey

Heap leaching in certain parts of the world, such as Chile's Atacama Desert, brings unique design problems in the form of possible large differential settlements of the foundation soils due to the dissolution of salts in northern Chile the soils often contain very high concentrations of soluble salts (nitrates, potassium, magnesium, and common sodium). When a leak in the liner occurs, the escaping solution dissolves these salts and triggers differential settlement. If the settlement is great enough, the geo-membrane tears, the leakage increases, triggering more differential settlement. The nitrate plants have experienced many occurrences of this phenomenon where a brine pond will undergo a sudden and complete loss of the impounded liquors. The authors present a simplified technique to quantify the differential settlement resulting from dissolution and provide a method which can be used to select a geo-membrane with suitable flexibility under axi-symmetric (multi-axial) load conditions to tolerate the predicted settlement. (This paper was previously published for Randol Gold Forum 1996 [Ref. 6]).

Jan 1, 1997

By T. G. Sitharam, P. B. Choudhury

Prediction of ground vibration (peak particle velocity, PPV) and frequency is an important task in geoscience. Till date, many empirical equations are derived from conducting trial blasts in the mines, to arrive at attenuation predictors. These predictors are usually site dependant and hold good for one particular type of rock/strata. These predictors cannot be used for geologically different rocks/strata. This paper presents the application of support vector machine (SVM) model, for predicting blast induced ground vibration and frequency, using a one comprehensive model for three different types of rock. Inputs to the SVM model formulation involve twenty one parameters consisting of geotechnical properties of the rock mass, blast design geometry and explosive properties, and the output of the formulated model is peak particle velocity and its associated frequency. The data has been acquired from eight limestone mine, five coal mine and two manganese mines. The comprehensive SVM model is formulated using 400 datasets and tested with 143 datasets. The performance indicators to the model not only justify its formulation but also the advantages it has over site specific predictor models. The SVM model not only predicts PPV, with higher correlation coefficients as compared to predictor equations, but also the associated frequency.

Jan 1, 2010

By B. Das

Waste water produced from coal preparation plants posses several problems during dewatering and solid/liquid separation. The natural sedimentation rate of the particles present in colloidal and finely divided suspended form is very slow. Flocculation technology is being applied in most of the coal washeries to recover water which is being accomplished through the use of inorganic salts, polymeric flocculants or both depending on the chemical and physical characteristics of the pollutants present in the waste water. The waste tailing water from Piperware coal preparation plant, Central Coalfield Limited (CCL), India, is highly turbid containing ~ 16000 NTU with negative surface charge in the pH range of 2 to 10. Polymeric flocculants in conjunction with fine magnetite is investigated to achieve faster settling rate with lowest level of water turbidity. The conditions affecting the interaction between the reagents and the turbid particles present in the tailings water are investigated. It is possible to bring down the turbidity of the water to < 90 NTU from very high turbid tailing water by using 2 mg/L of the polymeric flocculent in combination with 0.1 g/L of magnetite at natural pH of the tailing slurry. It has been found that finely divided positively charged magnetite particles in combination with the flocculent selectively coat the negatively charged impurities present in water and thereby increase the settling rate under the influence of a magnetic field.

Jan 1, 2014

By W. B. Berwald, T. W. Johnson

"The United States Bureau of Mines, in cooperation with the Natural Gas Department of the American Gas Association, has been studying actively for the past several years the flow of natural as through high-pressure pipe lines. 4 This report deals with that part of the study involving the design of pipe-line systems consisting of lines laid parallel to each other. The lines are referred to as the original line and the parallel line. The paralleling lire may or may not extend the entire length &f the original line; however, the parallel line is connected at its two ends to the original line.As a result of the large expansion of the natural-gas industry almost all markets within economic distance, from the developed as fields have at least one pipe line supplying them with natural gas. Small increases in the consumers' demand for natural-gas can be met usually by increasing operating pressures, but any marked increase in demand necessitates paralleling sections of the existing systems. It is believed that to a large extent future expansion in the natural—gas industry will consist of paralleling the present lines. The several formulas given in this report have been developed to aid in the design of such systems. Curves and tables were prepared from these formulas to simplify the calculations materially and to facilitate determination of the sizes of pine to be used in paralleling various diameter lines to give the most economical design. The formulas are presented without detailed derivations, as a complete report on the flow of natural gas through pipe lines is being prepared which will contain the derivations of these formulas. Examples included here show the detail of application of the several formulas to problems of design of parallel lines."

Jun 1, 1934

By Allan G. Provost

Shaft construction is assuming ever increasing importance when new mining enterprises are considered. The reasons for this increased emphasis is the much greater depths at which many new ore-bodies are being developed and the rapid depletion of near surface reserves requiring mines to go to greater depths on existing deposits. These greater depths increase the probability of exposure to unfavorable geologic conditions and it is more likely that high ground and/or water pressures will be experienced at these depths. The large capital costs involved and the critical position of a shaft in the overall mining program necessitate that this element of project development be given careful and critical consideration. The Henderson No. 2 Shaft is located in the Rocky Mountains of north central Colorado (See Figure I), about 55 miles west of Denver, near the community of Empire in Clear Creek County. At the 10, 442 foot collar elevation, winter arrives in late September and brings snow to contend with until May. The labor force for Shaft No. 2 is approximately 90 men. They are provided access to the project via all-weather U. S. Highway 40. SHAFT DESIGN The Henderson No. 2 Shaft is a 28-foot I. D. circular, concrete lined (1 foot thick) vertical shaft. The final depth will be approximately 3100 feet

Jan 1, 1972

By S. Chander

The formation of surface films on pyrite has been studied through electrochemical techniques of cyclic voltametry and AC impedance measurements. The characteristics of the surface films depend upon the conditions of oxidation and the source of pyrite. At potentials near 0.0 V, some pyrites have large values of polarization resistance showing a certain degree of passivity. Some pyrites show more passivation than the others, however. On oxidation, metastable phases of Fe(OH2) and Fe(OH3) form which transform to more stable 3 phases on aging. The growth of surface films near the corrosion potential of pyrite follows a linear kinetics which is attributed to a chemical (or an electrochemical) reaction as the rate determining step. The surface film is considered to be a hydroxide or an oxide rather than sulfur because the later is expected to be limited to a monolayer in alkaline solutions. This study has also demonstrated that AC impedance measurements can be used to study the growth characteristics of films at mineral/ solution interfaces.

Jan 1, 1987

By Frank G. Horino

A rock mechanics program (composed of laboratory and field tests) was initiated by the Bureau of Mines in an effort to determine the causes of pillar instability at the Fletcher mine, near Bunker, Mo. Compressive strength, Young&apos;s modulus, shear strength, and the angle and coefficient of internal friction were determined on drill cores obtained from 16 different locations in the mine. Results of the laboratory tests showed that highly mineralized zones and brecciated zones in pillars could significantly affect pillar strengths and stability in locations where extraction ratios exceeded the normal design ratio of approximately 78%. High-angle fractures that were present in Some locations also may have contributed to pillar deterioration. In the field tests, in situ stress determinations were made in one pillar to establish the pillar-loading conditions and to evaluate the stability of the pillar. Continued monitoring of stresses in the pillar showed a gradual decrease in compressive stress, indicating that the pillar was probably in the postfailure state. A second stress determination was made in a vertical hole in the underlying igneous rock that was exposed on one section of the mine. Horizontal stresses were compressive and larger than would be expected from gravity loading.

Jan 1, 1978

By J Samosir, L A. Snyman

Northparkes is located 27 km north of the township of Parkes in central New South Wales, Australia. The operations consist of underground block cave mines and an ore processing plant that produces high-grade copper and gold concentrate. Production is currently sourced from the E48 Lift 1 block cave mine and open cut stockpiles. Mining commenced at Northparkes in 1994 as an open cut operation. Underground block cave mining began in 1997. Northparkes was the first mine in Australia to use the highly efficient block cave mining method, which relies on gravity and natural rock stresses to fragment the ore.An issue affecting production in 2011 was the stability of the E48 mine. A small portion of the drives on the extraction level began to deteriorate as the ground support system failed. The problem was temporarily fixed by stopping production in three extraction drives and tight filling selected areas within these drives (and drawpoints) with low-strength concrete. This action provided immediate support and stability whilst allowing time to investigate potential ground support remedies. From these investigations it was decided to use resin injection technology and additional ground support to stabilise the rock in the aforementioned extraction drives as the concrete plug was excavated in a controlled advance and sequence. This made the area safe and ensured the ongoing safe operation of the E48 mine. The redevelopment of one of these drives began late in 2011, with the remainder being progressively redeveloped over the next two years in order to maintain the extraction level stability.This paper looks at the strategies employed to safely re-open previously converged drawpoints and associated extraction drives that were subject to high abutment loading that was possibly associated with premature cave breakthrough.CITATION:Samosir, J and Snyman, L A, 2014. Redevelopment at Northparkes following significant drive closure, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 87–92 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By V. A. Marple, K. L. Rubow, Y. Tao

"A personal diesel exhaust aerosol sampler has been designed and evaluated in both laboratory and field settings. The sampler uses size selective sampling for the determination of the respirable mass concentrations of mineral dust and diesel exhaust particulate matter found in underground coal mines. This design is based on the premise that diesel exhaust particulate matter is predominantly less than 0.8 um while mineral dust is greater than 0.8 gm. Operating at a flow rate of 2 L/min, the sampler consists of a 10 mm Dorr-Oliver respirable dust cyclone followed by an 0.8 gm cutpoint impactor and an afterfilter. Field evaluations consisted of sampling at 6 different locations in these underground coal mines. Measured aerosol concentration less than and greater than 0.8 um have been compared with a well characterized cascade impactor.Techniques must be developed for measuring the mass concentration of diesel exhaust particulate matter found in underground coal mines due to the health concerns associated with worker exposure to diesel exhaust particulate matter. Diesel exhaust particles are in the respirable size range and have been regarded as a potential occupational carcinogen by NIOSH (1988). Furthermore, a 1988 MSHA advisory committee directed MSHA to develop a sampling protocol for assessing worker exposure to diesel exhaust particles.The University of Minnesota and the Bureau of Mines, over the past 4 years have measured the size distribution of diesel exhaust particles and mineral dust, both in the laboratory and underground mines (Cantrell, 1987; Cantrell et al., 1987; Cantrell and Rubow. 1988; Marple et al, 1986; Rubow et al., 1988: and Watts et al., 1989). To date, measurements have been made in nine coal mines. Seven mines utilized diesel-powered equipment at the mine face while two used electric-powered equipment. The results of these field tests indicate that mineral dust and diesel exhaust particles can be differentiated on the basis of particle size. The measured particle size distributions have been found to be bimodal with a saddle point at 0.8 um. This has led to the hypothesis that one method for measuring worker exposure to diesel exhaust particles would be to collect size fractionated particle samples separated at 0.8 um with the diesel particles being less than 0.8 um and the mineral dust particles greater than 0.8 um.Aerosol size distribution measurements, using a micro-orifice uniform deposit impactor (MOUDI), have been conducted in the mine intake air portal, intake entry to the working section, haulageway, and section return entry. The MOUDI is a ten stage cascade impactor with particle cutpoints ranging from 0.1 to 15 um aerodynamic diameter (Marple and Rubow. 1984b; Marple et al., 1989). The sampling flow rate is 30 L/min."

Mar 1, 1992

By E. B. Wright

THE property of Falconbridge Nickel Mines, Limited, is in Falconbridge township, approximately thirteen miles northwest of Sudbury. From the mine and townsite, a gravel road leads to Sudbury and a branch line of the Canadian National railway to Sudbury Junction. The ore deposit is at the southeastern corner of the &apos;Sudbury Basin&apos;. It lies in a sheet-like mass, striking in an east-west direction, between norite to the north and greenstone to the south. The general attitude of the ore-body is vertical, but with frequent variations in dip of as much as 10° to the north or south. The deposit is very irregular in outline, the width varying from a few feet to eighty or ninety feet. In the vertical plane, rolls are frequently encountered. Gouge is very often present at one or both ore contacts. The norite to the north shows much jointing. The chief ore minerals are pyrrhotite, pentlandite, and chalcopyrite. The nickel content of the ore is usually double the copper content, average assays ranging from 2 to 2.5 per cent nickel and 1 to 1.5 per cent copper. The ore is of three main types: massive, breccia, and disseminated. The breccia ore, the most common type, consists of sulphides containing rounded inclusions of highly-altered country rock, which, in places, are so large that sorting is necessary in the stopes. In the norite, the breccia ore may grade into disseminated sulphides, which frequently are sufficiently concentrated for profitable mining. In places in the breccia ore, concentrations of solid sulphide masses occur. Until early in 1935, all mining at Falconbridge was by shrinkage scoping, but this method was found to be less and less suitable as greater depth was attained. When mining had reached the 1,000-foot level, ore drawn from large shrinkage stopes was found to have been diluted as much as fifty per cent by sloughing of the wall-rocks, caused by increased rock pressure and insufficient support. It was apparent that this method of stoping was un-suitable and -Mr. E. J. Martin was engaged to superintend the introduction of a method of cut-and-fill stoping.

Jan 1, 1938

By Nirmal Weerasekara

Mill liners serve the dual purpose of protecting the shell from wear and transferring the rotary motion of the mill to an effective grinding action. As the liners wear, the efficiency of energy transfer changes, so there is balance between liner profile for wear and for milling efficiency. A tool that can simultaneously predict the evolution of the liner profile and the associated change in milling efficiency should prove most useful in optimal liner design. This paper presents such an approach, based on measured 3D liner profile data informing 3D DEM simulations of charge motion and liner wear modelling.

Jan 1, 2012

By J. F. White

An experimental study was undertaken to evaluate the feasibility of a selective chloridizing roasting pre?treatment process for the elimination of impurities from zinc feed?stocks prior to recovering zinc by conventional unit operations. In this investigation, a number of chemistries that might serve as a basis for such a pre? treatment process were examined. A variety of chloridizing agents were admixed with EAF dust to promote the selective removal of lead and cadmium by the formation of volatile metal chlorides, he results of the experimentation firmly establish that selective chloridizing roasting is a technically feasible means of eliminating lead and cadmium from EAF dust. Excellent extraction efficiencies were accomplished with a number of chloride additives; as high as 98 percent lead extraction and 88 percent cadmium extraction were attained with minimal zinc losses, Continuous pilot?scale tests reinforced the trends established by laboratory?scale experimentation, Attempts of chlorine elimination using pyrohydrolysis were less successful. The extent of chlorine elimination was found to be highly dependent upon EAF dust sample type and treatment temperature.

Jan 1, 1996

By A. Valenzuela

During the last years, Chile has been the largest copper producer, either as concentrates or cathodes. Copper obtained via pyrometallurgy is produced by seven smelters, which have carried out modernization plans to increase smelting capacity or to achieve environmental regulations established in the Chilean legislation. Thus, the present work updates technological innovations in smelters, environmental regulations and presents solutions for SO2 handling, particulate matter and arsenic. Also, the authors emphasize the important role of CODELCO Chile, the most important state-owned copper company, in developing technologies such as EI Teniente Converter and EI Teniente Slag Cleaning Furnace,

Jan 1, 2003

By W. Rostoker

Packing Experiments The porosity and most of the other physical properties of a coherent mass of any material built up by the packing together of discrete particles will obviously vary with, and be governed by, the manner of association of the particles. The relation of packing to powder metallurgy has been discussed in some detail by at least two authors. Packing Theory Theories of particle packing have been put forward by C. C. Furnas and A. E. R. Westman. Although their approach to the problem is not the same, their conclusions are similar. In the process of packing, they visualize the voids of a uniformly sized material becoming filled with particles of a smaller size, and the voids between these being filled in turn with still finer particles. Obviously, if this process is carried ad infinitum, the resultant mass will have the same density as the constituent particles. In practice, of course, such a density of packing is never attained. In addition, the premise is made that successive particle sizes must fit into the voids left by the immediately larger particles- an assumption requiring definite size gradations and also particle shapes. It remained, then, for theory to correlate relative diameter ratios, and proportions and numbers of sizes of particles, for requisite packed densities. Briefly, the following principles were postulated: (a) For an infinite diameter ratio between largest and smallest sizes, an infinite number of particle sizes in proper proportion is required to give natural density. (b) For a given diameter ratio, there is a maximum number of permissible particle sizes for maximum packed density (Furnas). (c) Provided the particle shape is spherical, or approximately so, the proportions o particle sizes can be calculated. (d) The ratios of successive diameters of particles are in geometric progression.

Jan 1, 1947