Search Documents

By Julie N. Walker

This U.S. Bureau of Mines report reviews the first 2 years of the agency's progress in implementing total quality management (TQM), which the agency refers to as Quality Improvement (QI). All employees have been trained in basic TQM concepts, a cadre of facilitators has been selected and trained, and 13 Bureauwide teams are addressing specific issues that were identified by Bureau employees nationwide as problem areas. Also in place are a Quality Council composed of the Bureau's top executives, a Quality Management Board, and eight QI Working Groups to provide a national 01 infrastructure. There are also Quality Steering Groups at each Bureau location nationwide to address local concerns. In addition to the narrative text, the texts of salient memoranda and other documents are included as appendixes.

Jan 1, 1992

By I Lourel

In evaluating the installation of an in-pit crushing and conveying (IPCC) system for any mine, a number of options are available for each of the dig side, transport and dump side operations. Some of them are moreappropriate than others; given the pit arrangement, the material being handled and the rates at which it needs to be moved. This paper seeks to document the options that might be employed, and to rank them in terms of their applicability at any mine and their practicality overall, with a view to nominating those that would be most suitable for further study.

Jan 1, 2009

By Jessica Egan, Daniel Hodouin, Mohammed Reza Khalezi, Steve Bellec, Claude Bazin, Carl Duchesne

"A model for gold leaching was developed and implemented into a simulator. The simulator uses a description of the ore that is based on the mineral composition and precious metal content. The model accounts for the distribution of minerals and precious metals through the size intervals. An ore texture model based on precious metals and minerals grain sizes within the ore is used to predict the exposed surface of the species in the various size intervals. A model is proposed to predict the rate of dissolution of any species dissolution using the exposed surface, particle size, cyanide and oxygen concentrations, temperature, pH and agitation. The flow of slurry through a leaching tank is modelled using a parallel arrangement of perfect mixers to simulate a bypass and a Cholette-Cloutier mixer model. The simulator can be used for circuit optimization but was developed to provide an environment for learning the basic concepts of process analysis methods. Examples are given to illustrate the application of the simulator for planning tracer tests and sampling campaigns.INTRODUCTIONThe constant pressure to improve the operation of processes that are already close to optimum imposes to plant engineers to be aware of the available process analysis tools and to be able to use them to assess process operation and make a diagnosis to possible problems. Some of these tools are:•,Sampling the streams of a process;•,Data reconciliation;•,Analysis of mixing in reactors;•,Estimation of rate parameters;•,Optimal tuning and flow sheet modification;•,Automatic control and real time optimization.Although some of these tools are part of the curriculum of many university engineering programs, the students are not exposed to actual process analysis problems. In addition the complexity of the ore dressing processes compounded with unavoidable measurement errors and plant disturbances can discourage many motivated engineers. These factors often lead to an incomplete valorization of the collected data and a poor return on the investment associated with the sampling, testing and analysis of the samples.Simulators are readily available for process optimization (Yalcin and Shang, 2006) by allowing:•,The simulation of various flow sheet configurations;•,The simulation of a change of operating conditions;•,The simulation of various control strategies;•,The training of plant operators.However few simulators have been developed with the objective of providing an environment for training plant engineers and technicians to the use of tools for process analysis and optimisation."

Jan 1, 2008

By Robert M. Becker

This report (part 3 of a five-part series) presents computer programs for evaluating moments and moment relationships of the generalized probability distributions extended or developed in parts I and 2. The principal program is for evaluating the first three moments and moment relationships of the compound-multinomial distribution for finite as well as for infinite populations. This is the generalized distribution for sampling to some amount of items per sample. Another program is for evaluating the first four moments, the moments of the mean, and the moment relationships of the multinomial and generalized hypergeometric distributions. This is a general moment program in sampling to some number of items per sample or for sampling to some number of samples. This program will accept either ungrouped data, frequency data, or probability data.

Jan 1, 1965

By Phillip N. Yasnowsky

This Bureau of Mines publication tabulates State taxes levied on nonfuel minerals that have the characteristics of a severance tax.

Jan 1, 1978

By NEWTON B. KNOX

IN Bolivia, mining is still the principal economic activity, as it was before and during the Spanish Colonial period. Tin, tungsten, antimony, copper, lead, zinc, gold, silver, sulphur, and a little bismuth are produced. The Andes mountains are divided into two main ranges in Bolivia; the Western range marks the border with Chile and the Eastern range forms the backbone of the country; in the North it drops rather abruptly eastward, to the plains of the Beni, whereas in the South it splits and is separated from the Chaco flatlands by a series of folded mountain ranges. In general the mineral deposits are found within the Eastern range or in the hills that rise from the high plateau between the ranges - really parts of the Eastern range partly submerged by recent sediments. The mineral belt is thus over 500 miles long and about 100 miles wide and includes most of the principal centers of population and the most important means of communication. The region is mountainous and the roads are bad; furthermore labor is a serious problem, for the land is poor and the agricultural population is never far from hunger. The floating supply of miners is limited and soon exhausted in any emergency like the present.

Jan 1, 1945

By Robert W. Van Dolah

The prevention of fires and explosions involving the combustibles and oxidants likely to be found in flight vehicles requires a knowledge of the flammability and related characteristics of these materials. This circular is a compilation of the available charactersilics data for a series of combustibles and oxidants of current interest. Vapor pressure data are presented for fluorine, oxygen, chlorine trifluoride, nitrogen tetroxide, nitric acid, hydrogen peroxide, ethylene oxide, hydrogen, ammonia, pentaborane, unsymmetrical dimethylhydrazine, monomethylhydrazine, hydrazine, and a series of hydro-carbons including decalin, tetralin, bicyclohexyl and other high-density fuels. In addition, flammability characteristics diagrams are included for each of the fuels in contact with air and, where available, other oxidants (for example, oxygen and nitrogen tetroxide). To assist in understanding these data, sections on definitions and theory and applications have been included. Each section is complete in itself and can be used separately. For example, a reader who is familiar with the general theory of combustion and detonation may find the data sections more useful than the definitions and theory and the application sections. However, since pertinent data are included in these sections, they should also prove useful to the experienced engineer interested in preventing fires and explosions.

Jan 1, 1963

By VIVEK KASHYAP, Evody Tshijik Karumb, PATRICK TAYLOR

The partial reduction of zinc ferrite to zinc oxide and iron (II, III) oxide can enhance the leaching rate of zinc. Zinc ferrite has often been found as a major component of zinc residues and electric arc furnace dust. The Waelz process is an existing process for zinc ferrite processing, which requires a temperature of more than about 1200 °C to produce Waelz oxide containing ZnO. Since zinc residues have been deemed as a potential way for the extraction of zinc and other critical metals, it is important to analyze the reaction kinetics in the temperature range of interest. This manuscript discusses the chemical kinetics of zinc ferrite reduction by hydrogen gas. Several researchers studied the reduction of zinc ferrite with CO; however, unlike CO, the use of H2 gas as a reductant allows partial reduction of zinc ferrite even at low-temperature range (400–600 °C). Thermogravimetric analyses (TGA) experiments were performed in the temperature range of 300–700 °C with 10% and 30% H2, and the data obtained was analyzed using the isoconversional method of kinetic analyses. The standard models used for isoconversional kinetic analysis were chosen from literature and experimental data were fitted to determine the controlling mechanism and calculation of kinetic parameters of reduction of zinc ferrite. The rate of reaction was found to be increasing with an increase in temperature and partial pressure of H2 gas. The reaction could be divided into three stages, where reaction interface contraction was found to be the controlling mechanism at the initial stage of reaction. As the reaction proceeds, product layer thickness increases, and thus, diffusion was found to be the controlling mechanism. Roasting products obtained from TGA experiments were also characterized using a scanning electron microscope (SEM) to verify critical morphological details.

Jul 26, 2022

By William Gleason

"Caterpillar is the largest manufacturer of mining equipment in the world. In hundreds of surface mines around the globe, Caterpillar’s flagship 793 haul trucks can be found moving material for copper, coal, gold, iron ore and other mines. Likewise, its iconic yellow bulldozers are at mine sites the world over — the company recently announced the sale of its 40,000th large dozer. And since its acquisition of Bucyrus in 2011, Caterpillar has positioned itself to become a worldwide leader in the underground mining sector as well.But don’t think that the company is resting on its reputation. As evidence of its commitment to the global mining sector, as well as its confidence in the future of mining, Caterpillar invited mining trade press, including Mining Engineering, to its Tinaja Hills Training Center near Tucson, AZ in November to introduce the latest editions to its mining portfolio. The two-day event focused mostly on the newest electric drive haul trucks, the Cat 796 AC, which will operate in the 326-t (360-st) class, and the 798 AC in the 360 t (400 st) weight class.Caterpillar representatives also spoke about new offerings in the underground space as well as the newest version of the D11 large dozer.“It has been 10 years since we launched the F Series,” Jean Savage, Caterpillar’s vice president, surface mining and technology said. “Since then, we have been on a journey to serve our mining customers and we wanted to have trucks in every application. Today, we are launching two new trucks that will allow us to fill out our portfolio.”While Caterpillar previously offered the broadest range of off-highway haul trucks to the mining industry, it was noticeably absent from the 326-t (360- st) and 360-t (400-st) weight classes."

Dec 1, 2018

By M J. Bourassa

In addition to the geologic risk of a particular project, the criteria that an international exploration company (æIECÆ) utilises when making an investment decision in a particular country should also include a critical analysis of the political, judicial and fiscal regime of the host country. A key investment criteria of an IEC is mineral tenure and the security and continuity of that mineral tenure under the host countryÆs existing legal system as well as the host countryÆs overall legal, political and fiscal framework, the latter of which can affect the projectÆs overall economic viability in a number of ways. The authors, Steve Vaughan and Michael Bourassa of Aird & Berlis, Toronto, Canada, have taken the position that developing an understanding of a countryÆs legal tradition is a crucial first step in analysing the mineral regulatory regime of a particular country. This paper continues their efforts to overview the most recent legal trends affecting the worldÆs mineral industry and attempts to analyse, categorise, compare and contrast differing legal systems, cultural backgrounds and economic philosophies relating to the development of mineral rights in Pacrim countries and the resulting commercial, legal, and political framework which ultimately drives the relevant mineral legislation. For the convenience of organisation of this analysis, the authors have divided the Pacrim countries into four smaller groups, firstly, on the basis of their legal tradition and, secondly, by their geographic location:Common Law Countries: USA, Canada, Australia and New Zealand; Spanish Civil Code Countries: Mexico, Central America (Panama, Nicaragua, El Salvador, Guatemala), South America (Chile, Peru, Ecuador, Colombia). Communist or Former Communist Countries: Mongolia, China, Russia. Countries of the Pacific Southwest: Phillippines, Indonesia, Malaysia, Indo-China (Vietnam, Laos, Cambodia, Thailand), Papua New Guinea. The discussion starts with an analysis of the various types of legal regimes, attempts to classify or categorise them, reiterates the necessity for the rule of law and those factors which encourage mineral exploration and development and discusses and recommends the expansion of a practical country competitiveness rating system developed by the Fraser Institute. In addition to the fundamental issue of mineral tenure û what it is and how secure it is û the paper discusses how different legal systems have shaped different approaches taken by individual nations to attract foreign mineral investment. The paper analyses the best practices and experiences accumulated in different Pacrim countries with varying legal traditions and identifies a practical country competitiveness rating system which the authors believe should be expanded to cover all minerally endowed countries. This rating system will permit countries to identify their mineral regime weaknesses and adjust their legal systems to better attract mineral investment and will also permit exploration and mining companies to compare their jurisdictional choices with those selected by their competitors.

Jan 1, 1999

The æMountain Camp reefÆ at Alford's mine, Wakamarina,Marlborough, had no recorded gold production although assays of 5 - 26 g/t were reported, but it did produce c. l000 kg of scheelite. The lode consists of a lower massive quartz layer, and upper, cm-banded, ribboned quartz layers, and has a very low sulphide content. Within the massive layer, relict early fine-grained mosaic quartz with idioblastic scheelite is surrounded by recrystallised granoblastic coarse-grained quartz with calcite and plagioclase, in which an original ribbon banding texture is mimiced by strings of tiny inclusions. In both the banded and massive layers, rounded quartz grains, created by cataclastic milling of grain margins and along syn-vein fractures, have been partially annealed within later quartz overgrowths. Late fibrous quartz and calcite fill brittle cross fractures.   Deformation events D1 and D2 are associated with mid-late Jurassic metamorphism of the Pelorus Group, D2 producing the main regional schistosity (S2, and the earliest scheelite. D3 is an extensional mylonitic shear event that formed the dominant schistosity in Alford's mine (S3). The quartz lode was emplaced within the mylonite by a series of individual dilation pulses (D4). The D5 event caused crenulation of the S3 mylonite, kink banding and chevron folding of the S2 schist and S3 mylonite, and reverse faulting, rodding and cross-fracturing with late fibrous quartz-calcite veining of the D4 quartz lode.   Fluid influxes during successive dilations of D4 fractures progressively caused recrystallisation of earlier quartz bands on the footwall, annealing and recrystallisation of quartz along milled crystal margins and fractures, and deposition of minor sulphides. There was thus a dynamic interplay between fault dilation, lode fracture, fluid influx, lode band deposition, and lode recrystallisation. Illite-Kfeldspar al ¦ 2 Ma (K/Ar), c.30 Ma after metamorphism.

Jan 1, 1996

By S. W. Zoldok

"ERRATUMFor paragraph 1, page 1, read the following:The Cle Elum nickeliferous iron deposits occur on an unconformable contact between the serpentine and overlying Swauk sandstone formation and extend about 2 miles along the Cle Elum River in Kittitas County, Wash.The linear extent of the deposits and their proximity to a large source of,electric power and coal supply indicated that a development program was in order to determine the probable grade, extent of the ore bodies, and a suitable metallurgical process for recovering the iron, nickel, and chromium from the ore.The northern portion of the serpentine formation was investigated by the Bureau of Mines from August to December 1943 and from August to October 1944. The investigation consisted of road building, diamond drilling, sampling, and metallurgical tests.The Geological Survey assisted with logging of cores and made geologic and topographic maps."

Feb 1, 1948

The Rio Tinto Iron Ore group currently estimates grade attributes for mineral resources using ordinary kriging (OK). OK produces a smoothed globally unbiased estimate, but does not capture local variability, which can have significant impact on mine planning and scheduling. The dimensions and the multivariate nature of iron ore deposits make point simulations of whole deposits impractical. With a direct block simulation method the size and speed limitations of point simulations can potentially be overcome, resulting in a viable method for capturing local variability and for providing risk measures into the mine plan and schedules. Some iron ore deposits are highly folded (post mineralisation) and require preprocessing using an unfolding algorithm to properly define the continuity parameters and directions of anisotropy before simulation can proceed. Block co-simulation proceeds in unfolded space and since mine planning require a block-model with regular block-sizes; a regular block-model is unfolded first. This paper discusses a block co-simulation approach that can be used to simulate the irregular blocks resulting from the unfolding process. A section of an iron ore deposit is used for testing the block co-simulation algorithm and the simulation results are compared against the Isatis direct block simulation method. Available blasthole data is also used to validate the behaviour of the block co-simulation algorithm.

Sep 26, 2011

By G. David Baskin

Changes in the 1978 quantity and value of the sales of various natural abrasives, compared with the data for 1977, were of a mixed nature. Output of tripoli-type materials and garnet increased in both tonnage and value. Emery production also increased. But special silica stone product sales decreased in both tonnage and value, and the reported quantity and value of sales of manufactured abrasive material also decreased for 1978. In 1979 output of tripoli-type materials and special silica stone products decreased in both tonnage and value when compared with the previous year. The tonnage and value of sales of garnet and manufactured abrasives increased when compared to 1978 data.

Jan 1, 1980

By M. S. Klima, A. P. Pinkerton

Solid-bowl (decanter) centrifuges are used extensively to dewater slurries in a wide range of industries. However, the application of decanters as classification devices is not as common. In this study, the performance of a continuous, pilot-scale, solid-bowl centrifuge was evaluated when classifying an ultrafine coal slurry containing nearly 60% material less than 10µm. The current study examined the effects of operating conditions on centrifuge performance. The test conditions included centrifuge bowl and scroll speeds, volumetric feed rates, solids concentration, and pond depth. Centrifuge performance was evaluated using partition curves, along with product yields and solids concentrations.

Jan 1, 2000

By G. L. Oldright

This paper is the fourth of a series of preliminary papers on smelting in the lead blast furnace.4 The objects of this investigation are to determine the conditions obtaining within the blast furnace by direct experimentation and to correlate these conditions with operating factors, furnace behavior, and metallurgical losses. ACKNOWLEDGMENTS The authors wish to express their appreciation to the management of the International Smelting Co. at Tooele, Utah, for their whole-hearted cooperation in this investigation.

Jan 1, 1929

By C. H. Riggs, Kenneth H. Johnston

The application of modern secondary-recovery methods has made possible the the extraction of more than 13 million barrels of crude petroleum from the eastern part of the Delaware-Childers field Nowata County, Okla., over and above the production that might have :been expected by continuing primary production methods, including the use of vacuum. Foremost among the secondary-recovery methods used in this foil was the repressuring of the Bartlesville sand with air and gas through injection wells spaced on sym-metrical patterns. Between 1925 and 1945, about 51 billion cubic feet of air and gas were injected into the producing formation, and the total recovery was increased from, 25 million to about 40 million barrels of oil. To produce as much as possible of the 28 million barrels of recoverable oil remaining in the sand will require the initiation of systematic water-flooding projects on many properties and the continuation of air and gas injection on others.

Dec 1, 1946

By George O. Lower

The use of cyanides in the extraction of gold and silver is well known.1 Such extractions employ con¬centrations of cyanide in the range of 0.02-0.25 % sodium cyanide equivalent in leaching cycles of 24-48 hours and frequently longer. Copper minerals, even though minor components of precious metal ores, dissolve in these cyanide leaching solutions, consume cyanide, cause fouling of mill solutions, and thus interfere with the precipitation and recovery of gold and silver. 2,3,4 This paper presents a summary of laboratory investigations on the use of cyanide solutions as extractants for copper from various copper-bearing ore fractions. In view of the metal contents involved, it will be apparent that larger quantities of cyanide are required to extract copper than for the extraction of precious metals. In cyanide solutions of concentrations generally favorable to copper extraction, sulfide and oxide copper minerals were found to dissolve rapidly at room temperature and atmospheric pressure. For example, on products in the flotation size range, the major portions (e.g. 65-85%) of the extractable copper frequently dissolved in 2-10 minutes. At coarser grinds, e.g. 100% minus 28 mesh and 100% minus 10 mesh, 75-85% of the total copper was extracted in 30 minutes.

Jan 1, 1966

By Tom Palangio, Ralph M. Olmstead

Video inspection of boreholes with cameras developed specifically for the mining industry is now possible. These designs are reliable, cost effective, and have the flexibility to be used in other applications.

Jan 1, 1998

By Thomas Lardner

Excavation for The Bow, EnCana, in downtown Calgary, occurred between May 2007 and September 2008. A monitoring programme was used to determine the behaviour of the shoring wall, soil and bedrock during the excavation for the 21 metre (69 ft) deep excavation with a footprint of approximately 17,000 m2 (183,000 sq ft). Results from the inclinometer readings indicated that significant horizontal movement due to a weak rock layer and shear band effect. These modes of movement account for up to 100 mm (4.0 in) and 45 mm (1.8 in) of lateral deflection, respectively. Based upon the results of the monitoring programme, rock samples were collected from the weak mudstone bedrock, with great difficulty, to determine the strength and deformation parameters. Results from the uniaxial compression tests indicate a UCS around 830 kPa (120 psi) and elastic modulus between 80 and 180 MPa (11 and 26 ksi). Mohr-Columb parameters were determined to be c' = 340 kPa (49 psi) and f' = 24°. Residual strengths were determined to be c'r = 0 and f'r = 15°. Using the results of the laboratory tests and field investigation records, an initial finite element analysis was conducted. Results of the analysis show good correlation when compared with the observed monitoring deformation, indicating accurate portrayal of rock parameters. Additional analysis and investigation is required to determine the principal horizontal stresses in magnitude and direction.

Jan 1, 2010