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By J. A. Eisele

The Bureau of Mines conducted bench-scale cyclic tests to determine the composition of recycled leach liquor in the Bureau?s proposed clay/HCl leach/ HCl sparge process for producing Al203 from clay. The data developed from these tests make it possible to synthesize leach liquors for predetermined steady-state operating conditions when conducting large-scale crystallization tests. The results of two sparge tests were compared. One was a 20-cycle test with a 36-pct-HCl concentration in the mother liquor; the other was a 10-cycle test with a 26-pct-HCl concentration in the mother liquor. The effect of impurity concentrations in the leach liquor on the purity of aluminum chloride (AlCl30?6H20) crystals was determined, but there was poor correlation between this data and results that have been obtained from miniplant-scale work.

Jan 1, 1980

By E. Galán

The largest Spanish kaolin deposits formed on granites occur in Galicia (NW Spain) due to a widespread kaolinization of Variscan granitoids. This paper provides insight of the origin of this kaolinization process on the basis of a mineralogical and geochemical study carried out in two kaolin deposits, presently mined to be used in the paper industry. Mineral composition of the deeply kaolinized rocks is dominated by well-ordered kaolinite with minor quartz, K-feldspar, mica (illite/muscovite), locally gibbsite, and traces of resistant accessory phases (rutile, ilmenite, zircon and monazite). The content and structural order of the kaolinite decrease with depth. Kaolinite formed by extensive replacement of feldspars (plagioclase). Differential mobilization of major and trace elements during kaolinization has been inferred by using a mass-balance approach. Significant amounts of Na, Ca and minor Mn, Sr, P and U were removed from incipiently leachable minerals (plagioclase and apatite), and K, Rb, Cs and Ba were released from K-feldspar and mica. On the contrary, Ti, Zr, Th, Hf and the REE are retained in the resistant trace minerals that are concentrated in the fine fractions of the kaolins.

Jan 1, 2010

The Golden Cross mine commenced production in December 1991. Both open pit and underground mines produce 1000 tonnes of ore per day. Mining techniques are discussed along with results and variations to proposed methods of extracting the ore.

Jan 1, 1992

By Staff

One hundred thousand miles of flying over the North country without a single air casualty; much of it over virgin territory probably never before visited by white men; some of it over regions that abound with possibilities for minerals; all of it effective, for exploration and the establishment of bases and supply-stations, and for the carrying of men and their tools and provisions- this, briefly, is the record of Northern Aerial Minerals Exploration, Limited, a Canadian company organized Jess than nine months ago, which has been functioning, without interruption, during spring, summer, and now into winter. Our planes have ranged from the Alaskan boundary on the west to the Labrador coast on the east, and from the Transcontinental railway north to the Arctic circle. Our prospectors, carried on trips of hundreds, and occasionally thousands, of miles, have gone over large sections of country which were never before explored, and at the end of the prospecting season the Company finds itself in possession of several groups of important gold claims, which look most promising. In addition to this, we have been in contact with deposits of almost every known mineral.

Jan 1, 1929

By Madan Kumar Annam, Hari Krishna Y

"Basement construction is one of the challenging geotechnical concerns in the urban environment. Several types of retention systems are practiced to support the earth which is suitable for restricted access, rapid mobilization, fast excavation and cost-effective designs. A thorough understanding of geotechnical engineering as well as the structural mechanics is important for the earth retention systems. This paper discusses a project with various types of foundation solutions including monitoring of deflections during excavation stage of a retention system.A multi storeyed residential building (3B+Stilt+18F) in Chennai having structure foot print area of 1500 m2 has to be constructed on large diameter pile foundations and also to support the proposed basement excavation. Ground water table was encountered at about 6m below the existing ground level (EGL). In order to support heavy structural loads, large diameter bored cast-in-situ piles were chosen and installed. Further, complete retention system was economically designed and built, which includes installation of Contiguous Bored Piles (CBP) in combination of vertical grout columns behind CBP wall to seal the gap between the CB Piles, installation of inclined ground anchors, construction of capping beam, stressing and locking of installed ground anchors. A detailed monitoring program was in place and continuous monitoring of wall deflections is being measured at the time of publishing this paper. This paper describes the design and construction aspects adopted for foundation and retention system including the monitoring results during excavation stage of the project.INTRODUCTIONIn general, stage wise open excavation will be opted for basement construction where plenty of space is available. Due to urbanization and restricted space, open excavation became a difficult task nowadays. To overcome this problem, suitable retention system need to be selected to retain the soil mass. Selection of suitable retention system for multi-level basement excavation is a great challenge in geotechnical industry, especially when the proposed site is located within the minimum set back distance from the existing structures. This in turn calls for the advanced and innovative methods of retention system.Several earth retention systems such as Diaphragm Walls, Secant Pile Walls, CBP system, Soldier Pile Walls, Sheet Piles, Deep Soil Mixing (block walls) etc. with or without inclined ground anchors are being practiced worldwide. Considering the advantages and disadvantages of the available retention systems in practice locally and keeping in view of present site conditions, the developer has chosen CBP system with inclined ground anchors so that all foundation related works of the project will be handled in a single package. The main advantage of such packaged solution will ease the coordination between design consultants and foundation contractor resulting in faster construction of foundation works which in turn reflect savings in time and cost."

Jan 1, 2015

Mr D. Twigg graduated in Metallurgy at the Sheffield Polytechnic, and later obtained a Master of Science degree at the University of Bradford. Mr I.D. Matthews matriculated at Roosevelt High School and joined the No. 1 Parachute Battalion in 1968. He worked in Zimbabwe for 31 years in geological prospecting, civil engineering, and open-pit mining.

Jan 1, 1985

By Don Z. Painter, Gordon F. Revey

Frontier/Traylor Joint Venture is presently constructing a section of the Tri-County Metropolitan Transit District of Oregon's (TRI-MET) Westside Light Rail system. This new section will extend Portland's existing transit system to the western suburbs of Beaverton and Hillsboro. The drill-blast excavations at this project include 10,000 feet of 20 foot tunnel, 18 cross passages, three shafts, an underground railway station, and a U-wall open cut. From a blast designer's perspective, this job has been extremely challenging. Blast vibration is limited to 0.5 ips at 200 feet or at the nearest structure, and airblast is limited to 129 dB -- linear peak and 96 dB -- C scale. The tunnels pass under heavily built up areas and have top of tunnel to surface cover distances as low as 70 feet. Surface blasting in the 26,000 cubic yard U-wall excavation was limited to five short nighttime periods due to its proximity to the very busy highway 26.

Jan 1, 1995

By Yi Luo

A longwall mining operation went under a tall, self-supporting and free-standing wireless communication transmission tower. In anticipation of that the ground subsidence process might affect the transmission tower, the mining company took a proactive approach to mitigate the expected subsidence influences. The efforts include prediction of surface subsidence process at the location of the tower, assessment of stability, structural integrity and functionality of the tower structures, and design and implementation of mitigation measures. The intension of this paper is to demonstrate the techniques that can be used to assess and mitigate the subsidence effects on tall self-supporting and free standing tower structures.

Jan 1, 2008

By D. T. Pritchard

"Introduction""No accounting system is very good, and all of them are infinitely variable*.”The purpose of this chapter is to discuss those facets of a typical accounting system which are most commonly encountered by operating managers in mineral processing plants. However, before concentrating in any detail on these it is important to understand the broad purposes and basic techniques of any accounting system in any major business.The three broad purposes of an Accounting System are:- Administering, controlling, and recording the flow of cash in and out of the business. Cash is, of course, converted into other assets (or stores of value) such as inventory, plant and equipment, etc. These assets also have to be administered, controlled and recorded.- Internal reporting to Management for information, for control, and for use in making business plans and decisions. - External reporting to stockholders, government, lenders and other outside parties.In this chapter we shall organize our discussion of accounting practice in mineral processing plants around these three purposes of accounting and focus in some detail on specific practices and techniques with which operating personnel will be routinely involved. This chapter is divided into the following: Accounting Basics; Administration, Control and Recording of Cash Flows; Internal Reporting; Planning and Budgeting; Cost Control; and External Reporting."

Jan 1, 1989

By J. W. Wilson, P. C. Graham

SUMMARY The Witwatersrand quartzites in which South African gold mining operations are moat exclusively conducted, are notoriously difficult and costly to drill. Despite this situation, however, with the high cost of developing new mines and extending existing mines, together with the rising cost of labour and mining problems resulting from the ever-increasing depths of workings, the demand for raise-boring in these formations is increasing rapidly. Not only is the demand for raises and shafts increasing, but also the length and size of these excavations. Raise-boring studies carried out in South African gold mines have indicated that increased penetration rates and possibly reduced costs could be obtained if higher thrusts were available at the reaming head. Until fairly recently there has been no raise-boring machine suitable for underground use that possessed the thrust and torque characteristics necessary to achieve high penetration rates in hard abrasive quartzite formations and the cutters available were not really developed for high loading. In response to these requirements a raise-borer, the Robbins 83R was designed and built in Seattle, U.S.A. for the Anglo American Corporation. This machine is operating in South African gold mines and is currently being used at a depth of 12 000 ft below surface in one of the. Group's mines. The initial raises bored have substantiated that increased penetration is attainable at high thrust and it is now apparent that the machine is sufficiently versatile to drill raises of up to 12 ft in diameter in quartzite formation over a length of 2 000 ft.

Jan 1, 1974

By Frank Sames

Most Blasting Programs are developed focussing on the environmental impact with respect to blast vibration and airblast. Compliance with existing regulations or policies limiting the immissions are generally achieved through constrains in the blast design, or monitoring programs. Efficient monitoring programs combine compliance monitoring and blast assessment. Signals, which are obtained in the area of direct influence of the seismic source, can contain valuable information about the blast design parameters. Techniques to analyze blast vibration signals have advanced and can assist in understanding the contribution of individual blast parameters to blast vibration and airblast. Advanced signal analysis encompasses magnitude analysis, Fast Fourier Transforms (FFT) and frequency scans in the frequency domain, as well as filtering in the time domain. Through examples, the advanced signal analysis techniques and their limitations are described and discussed, showing the impact of blast timing, timing accuracy, charge configuration and the geology dependent transmission behavior. Optimization criteria and pragmatic monitoring programs can be developed on the basis of the most influential blast parameters. In addition, however, safety and the cost efficiency of the blasting program are essential to the success of an operation. That is where advanced signal analysis techniques can interface with blast planning, computer assisted modeling and information systems. A valuable process can be developed to ensure compliance with existing regulations and efficient risk management for mining operations, while tracking cost and supporting operational decisions. A conceptual blasting information system is presented.

Jan 1, 2000

By Kenneth Eilerts, Vincent Smith

"INTRODUCTION Knowledge of the Phase relations of fluids produced from combination wells 4/ at the pressures and temperatures characteristic of production from natural reservoirs is essential to efficient recovery and refining practice. An accurate sample of the fluid from such wells may be prepared by mixing (in the proportions of the measured gas:liquid ratio) gas and liquid taken from the separator conditions of steady flow; and physical properties of the sample, at significant pressures and temperatures, may be determined with suitable laboratory apparatus for use in the solution of engineering problems. The results of study of sample so obtained and of mixtures of gas and liquid from the separator combined in other proportions are presented in this report. Attention was given in the study to the relationship between the physical properties of what may be regarded as the constituent materials - the gas and liquid taken from the separator - and the properties of mixtures of these constituents. Data obtained for the complete range of mixture Proportions are expected to provide a reference scale for the study of other combination-well fluids produced at different liquid:gas ratios."

Apr 1, 1942

By B. J. Arnold

During the past three years, coal samples covering a range of coal rank, ash content, size consist, grindability, and moisture content have been tested for their flow properties using a triaxial shear tester that measures the unconfined yield strength in a compressed sample of coal. The ratio of this unconfined yield strength to the sample bulk density is part of the equation used by handling system manufacturers to calculate the critical arching or critical ratholing diameter needed to ensure that coal will flow from bunkers or bins. This ratio also serves as an index to compare the flow tested. To test the applicability of the index to predicting problems with coal flow, a series of tests were conducted at CO Inc.'s Coal Quality Development Center (CQDC) in Homer City, Pennsylvania. Tests covering ranges in size consist, moisture content, and ash content were conducted by first filling a small two-ton bin with coal and then emptying the bin at a pre-set discharge rate. The actual discharge rate from the bin under the various conditions tested was measured. Samples of the coal discharging from the bin were collected. One sample was analyzed for ash, moisture, and size consist; another sample was sent to the Iowa state University for trivial shear tests (supplying an index measurement). Actual flowability results from the bin were then compared to the measured index to determine the applicability of the handleability index in actually predicting coal flow problems. This paper describes the correlation between handleability index and bin flow and explains the next stages of the project.

Jan 1, 1992

By Rodney D. Rosenkranz

Energy consumption in domes tic copper production has increased nearly 60 percent in the last 10 years, reaching approximately 175 trillion Btu in 1973. Energy required to produce 1 pound of copper rose from nearly 41,000 Btu in 1963 to nearly 50,000 Btu in 1973. Production from lower grade ores and strict pollution control regulations have contributed to this increase. Each stage of copper production has been analyzed to determine total energy consumed, energy mix required, cost of the energy, and recent or proposed changes in operations which may affect the consumption of energy by the copper industry. Data have been gathered from a recent Bureau of Mines canvass of the industry, from visits to copper operations, and from conversations with copper industry officials.

Jan 1, 1976

By Claude Bazin, Jalna Lamontagne

"The operators of mineral processing plants collect daily samples from strategic process streams with a view to prepare production balances to assess plant performances. The rules to minimize the risk of systematic sampling errors are known and applied in many mineral processing plants. The mass of the sample to be collected is calculated to yield a target measurement reproducibility considering the fundamental error associated to the sampling of heterogeneous material. This paper demonstrates that this practice is partly valid if one does not account for the time variation of the ore composition during the day. The concept is demonstrated using samples collected on a 30 minute basis from different streams of a gold ore concentrator. Results show that depending of the natural variability of the stream characteristics the mass of the daily samples may not be the critical variable to obtain reproducible measurements. On the other hand the number of cuts taken during the day could impact on the variance of the measurements obtained from daily samples.IntroductionMineral processing plants may treat several thousand tons of ore every day to produce concentrate or impure gold ingots. The operation and performances of these plants are monitored on a daily basis through the collection of ore samples from various streams of the processing circuit. The samples are prepared and assayed to obtain the concentrations of target elements that are subsequently used to calculate the mass flowrates in the streams of the circuit and ultimately the distribution of the target metals for the estimation of the plant performances (Morrison, 2009; Lachance and Leroux, 2016).The acquisition of representative and reproducible samples is therefore the first step in the characterization of plant performances. The term representative sample is used here to indicate an unbiased sample, i.e. a sampling procedure that does not introduce a systematic error. Rules for the collection of unbiased samples are reviewed in the literature by different authors (e.g. Morrison, 2009) and are not discussed in this paper. The term reproducible indicates the dispersion of the measurements around the average value of a characteristic of a stream meets an acceptable level of variance. The reproducibility of a measurement process (sampling and analysis) is assessed by the relative standard deviation or coefficient of variation of the measurement that is a function of the sampling and assaying errors (Morrison. 2009; Gy, 1979). Usually the focus is put on the fundamental error of sampling whose variance can be controlled by the choice of the primary sample mass or adequate particle size reduction during the preparation of secondary or tertiary samples extracted for the chemical analysis. When a sample is taken from a stream that exhibits a time varying characteristic, the obtained measurement exhibits a variability that is not only a function of the sample mass but also of the natural variability of the ore in the sampled stream. This paper examines this aspect of the sampling of a time varying process on the reproducibility of composite samples for a day of production."

Jan 1, 2017

By Gary R. Gavan

This report presents the results of a research project that gathered detailed information on the composition of the population of mobile equipment used in U.S. coal mines. A computerized data bank containing over 19,000 pieces of coal mine equipment in use in 1976 was prepared with a data retrieval program. Operator protective structure technology is reviewed; field problems experienced with ROPS are discussed.

Jan 1, 1978

By Dupuy. Leon W., R. T. C. Rasmussen, W. A. Calhoun

"INTRODUCTION For many years it has been known that low-grade manganese deposits occur in the bluffs along the Missouri River Valley. Frequent attempts have been made to develop the ore and to produce a marketalble commodity but they have had little success. Under pressure of the war emergency and the shortage of manganese, the attention of the Federal Bureau of Mines was directedtoward the deposits.Manganese-bearing shale occurs from a point near Pierre, S. Dak., down the river to the Rosebud bridge near the Nebraska line (1).5/ The Bureau of,confined its work to the more accessible central portion of the deposits near Chamberlain, S. Dak. The ore occurs principally as concretionary nodules in the form of iron and manganese carbonates (manganosiarite and perhaps some manganocalcite; rhodochrosite has not been identified). At the surface the carbonate is often broken down so that the oxide of manganese gives the nodules a black The matrix or host rock is generally known as Pierre shale, composed of ""interbedded layers of bentonite, an altered volcanic ash, and dissemi¬nated bentonite particles,"" (2) and montmorillonite-beidellite clay minerals (3). The shale weathers to the very sticky gumbo characteristic of South Dakota and well-known to hunters and travelers in the area.The area selected for the experimental mining and pilot-plant work discussed in this report lies about 8 miles westerly from Chamberlain and is a few hundred feet north of U. S. Highway,16, on land owned or controlled,by M. Q. Sharpe of Kennebec, S. Dak., and the General Manganese Corp."

Feb 1, 1946

By Hamid Maleki

A geotechnical monitoring program has been implemented at Energy West Mining Company for enhancing site-specific evaluation of longwall stress conditions. This program consists of underground measurements at five locations in two neighboring mining districts located in the Hiawatha and Blind Canyon Coal Seams under moderate to deep cover. Within the last five years, additional measurements, including data on recorded seismic events and face conditions, have been incorporated into the data collection program together with detailed geologic mapping of longwall gateroads. In conjunction with the measurement program, the authors have completed detailed boundary-element stress analyses of the mine plans. Models have been calibrated using the data from in-mine instrumentations and then routinely used for evaluation of mine plans at depths approaching 2,600-ft. The work has improved our understanding of load transfer, seismicity and yield pillar performance. It has identified areas of potential increased stress levels at certain longwall face positions and provided guidance to measures that could be considered to mitigate the potential for these increased stress levels.

Jan 1, 2009

By Peter Townsend, Sergei Diachenko, Allan Moss

The Palabora Mining Company has successfully extended the life of its operation by developing a 30,000tpd block cave underground mine below the now closed open pit. The process of transitioning from surface to underground mining has been technically, operationally and managerially challenging. This has been due to a number of factors; in particular, the development of a block cave in a very competent rock mass. The competence of the rock mass is clearly demonstrated in the open pit that preceded the block cave, one of the steepest deep open pit excavations in the world. With cave breakthrough, however, the pit was ?instantaneously? deepened by 400m causing a major failure of the northwest wall involving close to 100Mt of waste material.

Jan 1, 2006

By Jayant Khambekar

In a typical mining operation, run-of-mine (ROM) ore is crushed and screened to achieve a desired particle size distribution and then fed to processing equipment for further refining. For an operation to be profit-able, the ore handling system from the mine face to final product loadout must be reliable. However, the handling system components do not always perform as expected and production problems related to material flow occur. These problems include flow stoppages, limited live storage capacities, uncontrollable flow, segregation, spillage and dust emissions. These result in lost production, excessive maintenance, safety and environmental issues, and even structural failures, in some cases. Flow patterns Flow problems and their solutions can be best understood by first learning how bulk solids flow. As bulk solids discharge by gravity from a storage system, primarily two types of flow patterns can develop: funnel flow and mass flow. Figure 1 shows a schematic of these two flow patterns. In funnel flow, only a portion of the material is in motion during discharge, which flows toward the outlet through a channel that forms within the stagnant material. Funnel flow occurs when a hopper is not sufficiently steep and smooth to ensure flow along the walls or when the outlet is not fully effective. In mass flow, all of the material is in motion whenever any is discharged ? there is no stagnant material. Mass flow occurs when the hopper is sufficiently steep and smooth to ensure flow along the hopper walls. Shallow valleys are not permitted and the outlet must be fully effective. A third type of flow pattern, called expanded flow, can develop when a mass flow hopper (or hoppers) is placed beneath a funnel flow hopper or bin. The mass flow hopper is designed to activate a sufficiently large flow channel in the funnel flow hopper to avoid flow problems due to a rathole. The flow pattern in which a bulk solid discharges from a storage system strongly influences the flow problems that may occur in that facility.

Jan 1, 2009