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By K. Oraee

A comprehensive, harmonic and sustainable development has always been a real concern of state policy makers. To reach such development, regional planning is an approach which is widely applied. This paper deals with policies adopted by a given country with rich mineral deposits, in order to accomplish a mining growth as well as economic development in relatively poor regions. In this regards, first, some worldwide experiences belonging to China, with large scale mining operations and Nigeria with a small scale mining industry, are studied. The mining industry in Iran is then considered as a case study. The study continues by categorizing and prioritizing Iranian regions based on their mining potential and the degree of development, using statistical analysis and Taxonomy and AHP techniques. Results obtained serve to provide recommendations as to where capital investments in the mining industry would produce highest returns. The approach used, together with the practical policies suggested in this paper, can be used to adapt appropriate strategies for mining development in a way that contributes to regional development and a more effective income distribution.

Jan 1, 2012

By Bin Tang, Suping Yao

In the last decade, the copper industry in China has developed rapidly and attracted the world’s attention. The production capacity of refined copper has grown remarkably from 4.578 million tons in 2010 up to 9.029 million tons in 2018, accounting for about 40% of the global refined copper production. And now, China has become the biggest refined copper producer in the world. This paper summarizes the application of modern copper metallurgical technologies such as Outotec flash smelting/converting technology, Cyclone smelting technology, TSL (ISA/Ausmelt) smelting/converting technology, Jinfeng side blown smelting and Baiyin side blown smelting technology, Chifeng side blown smelting and continuous top blown converting technology, SKS bottom blowing technology, Dongying two-step smelting technology, copper electrorefining with high current density, etc. in China’s copper industry, analyzes and compares the characteristics of those technologies and presents the great efforts of China’s copper smelters in adapting to the increasingly strict emission standards and improving economic benefits of copper smelters. INTRODUCTION China has been the biggest refined copper producer in the world for many years. China produced million tons of refined copper in 2018, accounting for 40% of the copper smelting production in the world, and of which, roughly, 70% of the copper concentrate was imported, mainly from Chile, Peru and Australia. ICSG (International Copper Study Group, 2017) shows clearly the position of top 20 countries of copper production and copper mine production (Figures 1 and 2). Blast Furnaces, Reverb Furnaces and Electric Furnaces dominated China Copper Smelting for quite long time till 1980s. The first modern copper smelting technology (flash copper smelting) was introduced into China in 1980s, then followed by Noranda, Ausmelt and ISA. Since then, China copper smelting technology stepped into modern time. Since 2000, old processes (Blast Furnace, Reverb Furnaces and Electric Furnaces) were phased out and replaced by modern smelting technologies. China Copper Production has been increasing dramatically (Figure 3).

Jan 1, 2019

By William J. Douglas

This document describes the development of a conventional mining equipment data base, and an approach for conducting industrial engineering studies of arbitrary mining systems employing network techniques. Data was acquired through underground time studies. Each member of a four-man field team was assigned to a specific machine during each shift for which observations were conducted. Using digital wrist watches and networks describing the man-machine interactions, all events occurring luring the course of each shift were recorded on cassette tapes. The tapes were transcribed, coded, keypunched, and validated using computerized editing techniques. The resulting data files were processed to provide statistics relating to activity durations and event frequencies. The results were used to evaluate operator, machine, and system performance for each section which was observed. Equipment, reliability, and maintainability analyses were conducted using the industrial engineering data files in conjunction with historical information collected at the mine site.

Jan 1, 1976

[CONTENTS COUNTY NO. OF MINES MINE INDEX PAGE]

Jan 1, 1980

By J. G. George

A brief review of the silver industry is presented to set the stage for the analysis of the distribution of silver production by source from various types of mines in Canada and of the changing relationship between the total output of silver and the total output of base metals. The decline in the average grade of the Canadian mines is also discussed and a trend for the future is proposed. The report then examines in broader aspects the world primary silver production and concludes, in the section on outlook, that the effective supply in primary silver will grow at a rate significantly lower than the growth rate expected for base metals. A cumulative deficit of some 900 million ounces is projected for the period 1975-1980 and a further deficit of some 1,100 million ounces if projected for the 1980-to-1985 period.

Jan 1, 1977

By W. Dan Walker

In recent years the Federal Bureau of Mines tested and approved four new types of self-contained breathing apparatus and a facepiece designed for use with the McCaa 2-hour self-contained oxygen breathing apparatus. The Bureau also developed and perfected a battery-powered lifeline telephone for use in mine rescue and recovery operations. Some of this equipment is described in Bureau of Mines Information Circular 7413.4/ This publication is a revision of information Circular 7413 and presents pertinent information on more recently developed mine rescue equipment. The breathing apparatus described herein are 1/2- and 3/4-hour sell-contained types of much simpler design than the conventional 2-hour self-contained oxygen breathing apparatus ordinarily used by mine rescue crews; however, it is just as important to select rescue crews carefully and to train them properly in the use, care, and limitations of the newer types of apparatus as well as the older, established types, if the newer types are to be used safely. The Bureau of Mines recommends that 1/2- and 3/4-hour self-contained breathing apparatus be used only as auxiliary equipment in mine rescue and recovery work and that the capabilities and limitations of the apparatus should be well understood by those who wear the equipment.

Jan 1, 1957

By Frederick Felder

The paper point out the Angostura deposit is located in Colombia. The Angostura deposit, located within the Eastern Cordillera of Colombia is hosted by Triassic-Jurassic quartz monzonite and quartz diorite porphyries emplaced into Precambrian gneisses of the Bucaramanga Group. Silicification, pyritization, sericitization, alunite and pyrophyllite and other alteration and indicator minerals suggest a high sulfidation origin for the strong hydrothermal alteration. Major faults and shear zones occur in the area with NE, E-NE, E-W, WNW, NW and N-S directions. Analysis of geological results and structural modeling has also demonstrated that there is potential for additional high-grade ore shoots within the presently known mineralized structures. Delineating these structures should result in an increase of overall grade and contained ounces.

Apr 22, 2003

By Alexander Siefert, Steffen Pankoke

In the development of commercial vehicles as well as of passenger cars, the effects of vehicle vibrations on operating safety, health and comfort can only be predicted by numerical simulation when appropriate occupant models are available. Such models must be based on human anatomy and have dynamic properties of real humans in order to achieve realistic results. Since human dynamic behavior depend on posture and percentile, the occupant model needs to be adjustable to these parameters with respect to geometry and dynamic properties [1,2]. Dynamic Human Finite-Element-Model CASIMIR CASIMIR is a non-linear, dynamic finite-element-model of the human body. It consists of a dynamic model of the upper torso with head, neck, shoulders and arms as well as of a dynamic model of the lower extremity with pelvis and legs. The most important part is the lumbar area with dynamic non-linear models of the lumbar spine and of back and abdominal musculature. The frequency-dependent characteristics of the intervertebral discs and the effects of muscle activation and non-linear frequency-dependent muscle properties are included. In the latest stage of development, CASIMIR has been equipped with a compliant model of the body surface in the contact areas to the seat. This results in a very realistic transmission of static and vibrational forces into the human body, see fig. 1. Intense model verification and validation has been performed in all stages of model development, starting with validation of small components like intervertebral disc, ending with validation of whole-body-vibrations using measurements of the dynamic mass / mechanical impedance [4]. For an in-detail examination of stresses in the vertebral bodies and discs, a non-linear submodel of the lumbar spine with an increased number of degrees of freedom can be coupled to the whole-body-model, enabling the researcher to examine local effects of vibrations and single shocks on the lumbar materials. [ ] Since it is well known that human dynamic behavior is significantly affected by anthropometric data and posture, CASIMIR can be individualized to the anthropometric status of single individuals or to the mean values for specific percentile groups. Furthermore, posture can be adjusted to the seating conditions applicable to a specific vehicle. Posture modification capabilities include the variation of the lumbar lordosis [3].

Jan 6, 2006

By Joe Zhou

"Mineralogical characterization and metallurgical extraction of silver is challenging due to its complex mineralogy and chemistry. Over 200 Ag-bearing minerals have been identified and a silver-rich ore body would typically contain 5 to 10 different silver minerals. Silver can occur not only as discrete microscopic (visible) silver minerals but also as submicroscopic (invisible) silver in other minerals. During processing, silver may form passivation compounds such as silver hydroxide, silver sulphide, jarosite-like silver sulphate, silver halide or silver cyanide precipitate, all of which may negatively impact on silver extraction. Knowing the deportment of silver in the ore and its metallurgical products is important in flowsheet design and plant optimization. This paper begins with the classification of silver ores and minerals and a review of processing techniques, and focuses on the major mineralogical factors to explain why and how these factors affect silver extraction. Case studies are provided to demonstrate the application of silver process mineralogy in flowsheet design and plant optimization.INTRODUCTIONSilver was known to and utilized by mankind since ancient time. Actually, it was one of the earliest metals discovered and utilized by mankind after gold and copper.Silver is the whitest metallic element. It is rare, strong, corrosion resistant, and unaffected by moisture, vegetable acids, or alkalis. Silver is also resonant, moldable, malleable, and possesses the highest thermal and electric conductivity of any substance. The chemical symbol for silver is Ag, from the Latin argentum, which means white and shining. Although silver does not react with many chemicals, it does react with sulfur, which is always present in air at trace amounts. The reaction causes silver to tarnish, and consequently it must be polished periodically to retain its luster.Silver possesses many special physical characteristics and qualities that make it useful to a variety of industries. The photography industry is the biggest user of silver compounds. Silver forms the most light-sensitive halide salts, which are essential to developing highquality photographic prints. Silver also has the highest electrical conductivity per unit volume of any metal, including copper, so it is used extensively in electronics."

Jan 1, 2010

By T. Hadley, E. Catovic

"Northern Minerals Limited’s (ASX: NTU) flagship project is the Browns Range Rare Earth Project (the Project) located in Western Australia, consisting of a number of deposits with high value, heavy rare earth elements, in particular yttrium, terbium, and dysprosium. The deposits are dominated by xenotime mineralisation, which occurs within hydrothermal silicified and hematitic breccias. The Company delivered an initial JORC compliant resource estimate for the Project at the end of 2012 of 10,500 t of contained total rare earth oxides (TREO), which was increased to 28,084t of contained TREO in October 2013 and further enlarged to 47,997 t of contained TREO in February 2014. Concurrent with the growth of the Project resource base, significant progress has been made in developing the metallurgical process for the beneficiation and extraction of rare earth elements (REE’s) from the xenotime mineralisation. Development of the beneficiation circuit evaluated several process options and selected whole-ore flotation and magnetic separation, followed by flotation (hybrid circuit) as the two preferred flowsheets to pilot, following encouraging results on the bench of 83% and 86% recovery to a 20% TREO mineral concentrate respectively. Several downstream hydrometallurgical extraction flowsheets were evaluated. However, the following two preferred process flowsheets were ultimately selected for further detailed investigation during the prefeasibility study: 1. Sulphation bake, water leach, purification, oxalate precipitation, and/or calcination to produce a mixed RE oxide; 2. Sulphation bake, water leach, phosphate precipitation, caustic conversion, HCl leach, and oxalate precipitation to produce a mixed RE oxalate. Excellent heavy rare earth oxide (HREO) extractions (~ 90%) from beneficiation concentrates were achieved on the bench for both circuits, however flowsheet 1 was ultimately selected as the preferred flowsheet to pilot due to lower capital and operating cost. A mixed rare earth oxalate (42% TREO) or oxide (92% TREO) can be produced with low levels of Th and U of 3 ppm and 6 ppm respectively."

Jan 1, 2014

By Warder A. Shaver

INTRODUCTION Mine No. 95 of the Consolidation Coal Co., a divi¬sion of Continental Oil Co., is located in Shinnston, WV. Mine No. 95 was opened in January 1967 and has been operating continuously since that time. The mine has 544 hourly and salaried employees. In 1974 this mine was the largest coal producer in West Virginia. Opera¬tions include two longwall sections and eight Marietta Borer continuous miners. Originally there were also two Jeffrey Heliminer continuous miners, but use of these was discontinued in June 1978. Production averages 12 727 t/d (14,000 stpd). Two portals now service the mine with a third portal proposed for 1978. GEOLOGY Mining takes place in the Pittsburgh coal seam which dips 0.04 rad (21h°) northwest. The working seam is steam coal with an average height of 2.2 m (86 in.). Immediately above the seam, the overburden is com¬posed of 6.1 m (20 ft) of shales followed by 6.1 m (20 ft) of weak sandstone and 51.8 (170 ft) of shaley limestone. The shale weathers when exposed to mois¬ture. Surface water has been a problem due to a fire¬clay floor which turns to paste when mixed with water. GENERAL DESCRIPTION The present mining plan for Consol's No. 95 mine has a proposed life of 35 to 40 years. One set of main headings has been driven in the north direction and one set in a western direction. These are the areas in which the majority of the virgin coal lies. The panels are driven off of the mains at 2134 to 3048-m (7,000 to 10,000-ft) intervals. The continuous mining sections are set up 133 x 610 m (600 x 2000 ft). Longwall sections are 259 x 1220 m (850 x 7000 ft). All of these mining sections are retreating uphill. Development is with continuous miners. A Marietta Borer miner is used for the main development work. These miners cut 4.1 m (13 ft 6 in.) wide and 2.1 m (7 ft) high, leaving an arch cut. Along with the arch, a 152.4-mm (6-in.) thick layer of roof coal is left in place to protect the roof from weathering. The combi¬nation of the self-supporting arch and the roof coal al¬lows the entries to be driven 30.5 m (100 ft) without bolting. Full bolting, however, is carried outby the last open crosscut. This bolting is done on 1.5 x 1.5-m (5 x 5-ft) centers using 1.5-m (5-ft) long roof bolts with tandem anchors and 152.4-mm (6-in.) steel washer plates. When needed, crib blocks with a 50.4-mm (2-in.) drill hole are used as supplemental supports. Three-hole steel channel with the ends curved down¬ward to conform to the borer arch may also be used. In the mining sections, a 14 BU loader is used be¬hind the Marietta miner to load two Torkar shuttle cars. These haul to Long-Airdox feeder breakers which load onto a 1.07-m (42-in.) wide conveyor belt. With the exception of the shuttle cars, which use 275-V d-c power, the face equipment operates on 550-V a-c power. The main power line is 7200 V ac. The same loading and hauling equipment is used with the Marietta Borer miner for driving both panel and development entries. In the retreat sections, the same equipment with the exception of the miner is utilized. Because of the advantage of a variable cutting hight, Jeffrey Heliminer ripper-type continuous miners were employed in these retreat sections. For longwall mining the first unit uses an Eickoff EDW 300-L double-drum ranging shearer. Drum di¬ameter is 1.69 m (66 in.) with a drum rotation speed of 45 rpm. The drum is equipped with 48 Carmet 34-L-1 bits. The 300-kW (400-hp) motor operates on 1000 V. Tramming of the shearer head is done through a hydraulically driven 26-mm wide chain. Maximum cutting speed is 7.93 m/min (26 fpm), and maximum tram speed is 12.8 m/min (42 fpm) with an average cutting speed of 3.66 m/min (12 fpm). Web cutting depth is 762 mm (30 in.) and the cutting height is 2.13 m (7 ft). The conveyor width is 686 mm (27 in.). It uses a single chain, 26 mm thick, with flights on 0.91-m (3-ft) spacing. The face conveyor speed is 64.3 m/min (211 fpm) when driven by two 112-kW (150-hp) 1000-V Louis Allis motors through torque convertors. The roof support used is Gullick Dobson chocks [6-legged 77.3 t (85 st) per leg, 463.6 t (510 st) total capacity] with double-acting leg jacks. The hydraulic pressure for the legs is 13.8 MPa (2000 psi), and the hydraulic pressure for rams is 6.8 MPa (1000 psi). The yield valves are set at 57.8 MPa (8500 psi). Each chock weighs 4.09 t (4.5 st). The stage loader is an Eickoff drive, with a 68-kW (90-hp), (00-V Reliance motor. A 26-mm thick single strand chain with flights on 0.6-m (2-ft) centers runs at 75.89 m/min (249 fpm). The stage loader is self-advancing and is connected to the belt tail piece with a special fifth wheel attachment so that the stage loader can advance and guide the tail piece. The hydraulic pressure for the roof support is supplied by two 45-kW (60-hp) Reliance motors op¬erating on 699 V, with 1.26 L/s (20 gpm) constant volume Gullick hydraulic pumps. Each pump services alternate chocks, with the two pressure lines connected at the tailgate by 25.4-mm (1-in.) hydraulic hoses, rated at 27.21 MPa (4000 psi). The 6.8 MPa (1000 psi) pressure rams advance is supplied by a 45-kW (60-hp), 600-V Reliance motor and a 1.26-L/s (20-gpm) con¬stant volume Gullick pump. Return lines are 35.5-mm (1.4-in.) diam hydraulic hoses with rated capacity of 27.21 MPa (4000 psi). The fluid used in the hydraulic system consists of 95% water and 5% Hy-chock fire resistant water soluble oil. Water is stored and mixed in a 6096-L (2000-gal) track-mounted tank and goes to a 655-L (180-gal) reservoir at the pump. The belt conveyor structure is 1.07 m (42 in.) wide with 0.47 rad (27°) idlers, bottom stands located on 3.05-m (10-ft) centers, top stands on 1.5-m (5-ft) centers, and is supported on a 19-mm (3/4-in.) diam

Jan 1, 1982

General economic conditions continued to improve in the second quarter of 1984 as real gross national product advanced at an annual rate of 7.5 percent (table 1). This followed an even larger first quarter annual rate increase of 10.1 percent. The slower second quarter growth was greeted as a sign that the economy is not over-heating. The signs of slowed growth in some sectors suggest that the recovery may continue well into 1985 without the inflation symptomatic of a rapid recovery. Most of the slowdown in growth was absorbed by business inventories, personal consumption of durable goods, and residential fixed investment. Business inventories grew by only 68 percent as much as in the first quarter, personal consumption for durable goods grew by 58 percent of the first quarter rate, and residential fixed investment slowed to only 44 percent of the first quarter growth. Sectors with accelerated growth in the second quarter included personal consumption of nondurable goods and of services, which increased at annual rates of 9.6 percent and 3.8 percent, respectively, and Federal purchases of goods and services, which increased at an annual rate of 47.9 percent.

Jan 1, 1984

By N. R. Paterson, D. G. MacKay

"The geology of the Mattagami mining camp, while of particular economic significance, is unfortunately obscured by a very thick mantle of overburden. For this reason geo-physical methods have been relied upon heavily in exploring the area. Geophysical data over five important sulphide discoveries show how targets are selected for drilling and how effective geophysics has been in assisting subsequent development programs."

Jan 1, 1960

By John H. Weigand, Stephen V. Crum

"VIBRONICS, INC. instrumented and monitored a residential structure for response to,blasting at aMidwestern surface coal operation. The residence was owned by the mining company and was extremely close to the operation. Blasting was conducted within 120 feet (36.5 meters) of the test structure. Up to seventeen (17), four (4)-channel seismographs were used during the monitoring period. The basement walls and floor were monitored. VIBRONICS, INC. also monitored a brick chimney in the basement and attic. Structural responses were then compared to outside vibration measurements taken in the soil near the foundation."

Jan 1, 1998

By Scott Turner

The monetary metals , gold and silver , have recently been the object of such general interest that the United States Bureau of Mines has received many inquiries regarding them . Though requests for technologic information have been numerous , they have been exceeded in number by those concerned with economic aspects of these metals . The nature of the latter communications indicates that the public is not generally aware that various Bureau publications are available which deal with the economic situation of gold and silver . For this reason , it is deemed advisable to present a brief résumé of the papers which are obtainable from the Bureau or the Superintendent of Documents , together with the text of three articles recently prepared by the Director , reprints of which are not otherwise available . The Bureau of Mines compiles figures showing mine production of gold and silver , by districts and States , and cooperates with the Bureau of the Mint in determining the total annual output in the United States as a whole . 3 It recently established an annual canvass to determine the consumption of silver in the arts and industries of the United States , and published an economic paper covering such use in 1928 and 1929 , followed by an information circular on silver consumption by industry during the 2 years subsequent . A 4-year record is thus provided for those interested in utilization of silver . The Bureau has also published summarizations of all available data upon world production since 1493 of gold and of silver . It has , furthermore , rendered available a compilation of production- data of silver mines of the world , and an analysis of it , showing the proportions of silver and other metals contained in all the ores from which silver is derived . " All of these papers are concerned solely with putting into readily usable form statistical data and other factual material ; they do not offer theories or express opinions upon controversial questions related to these metals . Three other recent papers concerned with gold and silver are presented below in order to put them in shape for distribution by the United States Bureau of Mines . All three of them are by the Director of the Bureau . It should be noted that these papers do not commit

Jul 1, 1933

By R. L. Virta

Ball Clay -- Four companies - H.C. Spinks Clay Co. Inc. (owned by Lhoist Group), Imerys Group (formerly Kentucky-Tennessee Clay Co.), Old Hickory Clay Co. and Unimin Corp. - mined ball clay in four states during 2010. Production, based on preliminary data, was 910 kt (1.11 million st) with an estimated value of $42.9 million. That was a 10-percent increase in tonnage from 831 kt (916 million st) with a value of $37.7 million that was produced in 2009. Tennessee was the leading producer state with 61 percent of domestic production. It was followed by Texas, Mississippi and Kentucky. About 70 percent of production was airfloat, 20 percent was crude and 10 percent was water-slurried.

Jan 1, 2011

By R. E. Morgan, D. L. Douglass

The determination of phase relationships and solid-solubility limits can be performed by quantitative metallography in addition to the usual X-ray and metallographic techniques. For example, Beck and smith1 redetermined the ß/ß + ?, ß + ?/?, a/a + ß and a + ß/ß boundaries in the Cu-Zn system by measuring the volume fraction of second phase of several alloys and extrapolating the volume fraction-composition curves to 0 and 100 pct. A modification of this technique is suggested for certain alloy systems, in which it is not necessary to use several alloy compositions but merely one. A single two-phase alloy may be used to determine terminal solubilities in the following manner. The method consists of equilibrating samples of the alloy in a two-phase region adjacent to the desired solid solution, at three or more temperatures, quenching, measuring the volume fraction of second phase present, and applying an analytical treatment to calculate the unknown solid solution. However, two restrictions are inherent in this technique. They are: 1) only certain types of alloy systems are amenable to it, and 2) the general features of the system must be known. The first drawback to the new technique, i.e., that only certain types of systems may be studied, necessitates that the composition at one end of the tieline must either be constant with temperature or well established as a function of temperature. Either a pure metal or some intermetallic compounds fulfill the former. If it is assumed that the volume per gram-atom of a dilute solution is unchanged by the addition of element B to element A, the composition of the solid solution in equilibrium with the second phase may be determined by a material balance and is given by where X, = volume fraction of B in a solid solution Xc = volume fraction of B in compound c X = volume fraction of B in alloy f = volume fraction of second phase The composition by weight may then be determined by the use of tables in the Metals Handbook2 when the density ratio of the solid solution constituents is known. A possible alternative treatment involving the use of the lever rule is less precise than the above tech- nique. This may be used when the density of the solid solution is either known or may be calculated from X-ray data for several compositions. The following analysis is then made. The ratio of compound to solid solution (by weight) may be expressed as follows: x0 - x wc = xr-x = x0 - x r2i Xc -X where Wc = weight of compound w = weight of solid solution x, - alloy composition, weight percent x = unknown composition Xe = compound composition but where V, = volume of compound VA = volume of solid solution pc = density of compound p, = density of solid solution fc = volume fraction of compound fB = volume fraction of solid solution and fs = l -fc then If pc and xc are known, and f, is measured, then pB is the only unknown on the right side of Eq. [4]. The known densities of the solid solution can be plotted for various compositions and can then be expressed mathematically as a function of composition. The use of an expression of pB = f(x)reduces the equation to one unknown—the desired solubility. In the event that the densities are unknown, they may be calculated for various compositions from Vegard&apos;s law. The calculated values are then plotted and expressed analytically. The most accurate results are obtained for Eq. [4] when fc<< 1, i.c., when (x, -x,) - 0, &/l-f, - m; but as fc/l -fc - 0, (xl-x,)- (x, - x), and x - x,,. However, the accuracy with which fc can be measured decreases as f, decreases.3 Alloys for investigation must be selected by a compromise, which is based upon an error analysis of Eq. [4] and knowledge of the accuracy of volume fraction measurements. An examination of phase diagrams in the literature showed many which were amenable to the technique described here. The zirconium-copper system was selected in order to determine the solubility of copper in beta zirconium. Pieces of an alloy which was arc-melted three times were wrapped in tantalum foil and sealed under an argon atmosphere in Vycor tubes. The sealed samples were equilibrated at temperatures from 850" to 960°C for 3 weeks and quenched to room temperature by smashing the capsule in water. Several planes of polish were examined, and

Jan 1, 1960

By Y G. Anoman

This paper discusses the operating model within Endeavour Mining Corporation regarding the options of owner mining against contract mining. It’s based on the concept of ‘are we carrying out the most efficient mining’ regarding cost and performance. This question can only be answered through an extensive contract mining tender process and conducting a comprehensive comparison to evaluate the transition viability. Karma mine, located in Burkina Faso, is the subject of this paper. The Tender model included sales of equipment, parts and tooling associated with the traditional Load and Haul Schedule of Rates (SOR). The methodology focused on the structure of the tender process, which consists in the development of a SOR based on haulage profiles and mining schedule. This is a new Endeavour framework that allowed the bidders to compete on an even level. This was performed using a systemic analysis which encompassed all the elements involved in a transition such as the Human Resources (HR), taxes and customs implications, directs and non-direct costs (Finance and interest on assets, depreciation, insurance), contractor risk profiling. It was assessed against the normalised internal pricing tender-based. This paper gives an insight into how a West African mining operation addressed the sensitivities of the HR functions against the commercial aspects. This was one of the most successful transitions in West Africa and was carried out during the COVID crisis. The outcome of this project has created value by detailing a lesson learned model for both commercial and HR aspects. This discusses the commercial comparisons along with the internal model with the underlying HR functions as a risk factor that could have jeopardised the continuation of the operation. This resulted in a smooth transition with the additional cash flow generated by the sale of the parts and equipment turned Karma into a viable operation.

Jun 22, 2022

By Guillermo Turner-Saad

"Best practice in the economic evaluation of mining projects and operations is based on the integration of geological, mining, metallurgical, environmental, marketing, economic and corporate information and strategies. Fundamentally, the economic evaluation takes into account mining, blending, stockpiling, processing, smelting, refining and marketing ore resources with grades estimated by geostatistical methodologies.Nevertheless, a realistic economic evaluation consists of a concurrent and integrated optimization process that maximizes the concentrates or products of liberated and selected ore minerals from mineral deposits. The optimum solution is obtained through a trade-off among mining, blending, stockpiling and processing ore reserves with distinct mineralogy and texture characteristics. The concurrent optimization determines both the practical mining sequence of ore reserves and the dynamic and robust mineral processing flowsheet design over the expected life of mining projects and operations.A combined risk-adverse and concurrent optimization process takes into account the spatial uncertainty of the mineralogy and texture characteristics of ore reserves. Additionally, a variety of mineral processing linear, non-linear, additive and non-additive parameters modeled spatially. The spatial uncertainty of these ore reserves characteristics and parameters has a direct impact in the expected mining sequence, mineral processing flowsheet design, concentrates or products quantity and quality, and economic value of mining projects and operations.Geometallurgical domain constrained stochastic geostatistical methodologies and multivariate mathematical models are applied for spatial uncertainty modeling of ore reserves characteristics and parameters. These mathematical models correlate the mineral processing liberation and selectivity responses of the mineralogy and textures within each geometallurgical domain. These models, in turn, are defined based on results of mineral processing and environmental testwork of unbiased and representative samples chosen for their variability. These samples are selected within mutually exclusive spatial geometallurgical uncertainty domains with similar mineralogical and textural characteristics in mineral deposits.Geometallurgical domains are defined by applying and combining multivariate statistical analysis and implicit modeling methodologies. These involve determining and constraining mineral processing liberation and selectivity properties explicitly contained in the extensive and integrated exploration drillhole database."

Jan 1, 2010

By E. H. Burroughs

This bulletin is the fifth in the series of petroleum bibliographies publis:\:l.ed by the Bure.au of Mines, Bulletins 149, 165, 180, and 189 being compilations for the years 1915, 1916, 1917, and 1918, respectively. In this bulletin the same general plan has been followed in arranging the references, but a few changes and additions have been made in the classification.

Jan 1, 1923