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By G. Mike Bernard

The Andacollo gold mine is located near the town of Andacollo (population 14,000 people) in Chile’s region four. It is about 56km (35 miles) by paved road from the coastal city of La Serena. Santiago is about480 km (300 miles) south. Site elevation varies between 1,000 and 1,280 m(3,300 and 4,200 ft). The climate at the Andacollo site is moderate but arid. Average annual rainfall is only 130mm (5 in.). Because there is little rain and the temperature varies only a few degrees (14 to 24 C or 57 to 75F), there are no problems with freezing, solution dilution or pad saturation. The climatic conditions are ideal for heap leaching.

Jan 1, 1996

By Amila Sandaruwan Ratnayake, T. Dilmi. U. Wijewardhana, H. C. S. Subasinghe

The value addition potential of ilmenite was examined using several characterization techniques. Raw ilmenite is composed of 93.65 wt.% of FeOTiO2, 3.55 wt.% of SiO2, 1.22 wt.% of Al2O3, and the remainder being other minor oxides. Ilmenite and powdered carbonized coconut shells were mixed in the weight ratio of 4:1. A separate fraction of the same mixture was added with powdered seashells in the weight ratio of 4:1:0.5. Six fractions of each mixture were distinctly milled from 1 to 6 h in a planetary ball mill. XRD spectra (broadened and diminished reflections of ilmenite) and FTIR observations (Ti―O―Cbonding) of milled samples indicate the possible incorporation of carbon into the ilmenite structure. Any clues of an occurrence of new rutile peaks were not observed in XRD spectra of milled samples. Consequently, the carbothermic reduction has not been initiated during mechanical activation. In this case, samples powdered for 6 h in a mill were isothermally annealed for 2 h under normal airflow at temperatures of 800 °C, 1000 °C, and 1200 °C, respectively. According to the X-ray diffractograms, the annealing temperatures of 1000 °C and 1200 °C exhibited almost similar trends with rutile (R), pseudobrookite (PB) and elemental iron (F), and a very few ilmenite (I) peaks. Consequently, 6 h of milling and 1000 °C annealing were concluded as the optimum conditions for the carbothermic reduction. Moreover, this study indicated seashells as a potential rate raiser for the carbothermic reduction of ilmenite at 800 °C. Therefore, this process is applicable to upgrade ilmenite into a mixture of synthetic rutile and elemental iron.

Mar 29, 2021

By Fred C. Bond

The perennial subject of comminution is deserving of a fresh approach if one can be found. This is attempted here by directing attention primarily to principles rather than to theories. While theories attempt to explain how a certain process acts, principles delineate the laws which the action-must follow. Comminution may be defined as the progressive separation of particulate matter. At the present time this is accomplished commercially by applying energy in the form of compressive and, shearing forces. Such forces strain and distort the particles they contact. When-the applied stress locally exceeds the breaking strength at the weakest flaw in the particle, a crack tip forms. The surrounding strain energy flows to the crack tip, which rapidly extends through the particle as a break. The minute changes in shape and the resulting energy flow cause the failure of other highly stressed flaws, with the consequent formation of a progeny (1) of new smaller particles out of its destroyed progenitor. The applied mechanical energy is transformed into strain energy as the particle is distorted, and then into heat when it fails. Only a tiny fraction of the order of 1/1000 of the applied energy necessary for breakage appears as new surface energy in the product particles. The comminution problem is the relationship between, energy input and product particle size. Its solution is of great-economic importance,

Jan 1, 1961

By B. J. Arnold, N. Terblanche

The features of the ‘Turbo’ froth flotation column will be discussed, including the double aeration system that improves flotation yield while not sacrificing grade, the internal launder system, and the unique feed/tailings sump that evens out flow to the flotation column preventing upset conditions. Results from various test programs and installations will be presented.

Jan 1, 2001

By C. A. Carroll

In February of 1989 the Mission Complex of ASARCO Incorporated completed an expansion of its concentrator, raising the base mining rate from 25,900 TPO (28,500 STPD) to 37,200 TPO (41,000 STPD). The expansion was accomplished by extending the twelve existing Mission ball mills in length, by installing the grinding circuit from Asarco's idled Sacaton Concentrator along with various auxiliary equipment, and by modifications to the flotation circuit and water systems. This paper will give a brief history of the consolidation of the ore body which made the expansion possible and explain the various parts of the expansion.

Jan 1, 1990

By T. Clarkin

This paper presents a hydrologic closure design concept to minimize the risk of water discharges from closed mine tailings facilities. It evaluates the applicability of U.S. Nuclear Regulatory Commission guidelines to develop acceptable designs for the closure of tailings facilities that have a calculated adequate surcharge capacity for environmental protection and an emergency spillway for dam safety. The guidelines provide a basis to estimate an acceptable surcharge capacity of a Probable Maximum Flood series for storage of surface runoff. To be conservative and for redundancy with respect to dam safety, an emergency spillway is provided to pass the Probable Maximum Flood. Depending on the annual water balance, the surcharge capacity may be used by surface runoff and minor amounts of sediment that accumulates in the impoundment from year to year. The emergency spillway crest is then set at this level or above the surcharge capacity, whichever is higher. An example is given of the active Red Dog Mine tailings facility in Alaska where this method was used for the preliminary design of the tailings main dam at its ultimate closure configuration.

Jan 1, 2012

By J. D. Miller

The sedimentary western phosphate deposits of Idaho, Montana, Utah, and Wyoming tend to be calcareous and generally carry a significant amount of dolomite along with collophanite. In some cases, such as the Smokey Canyon Mine, Afton, Wyoming, the ore will also contain mudstone, and in this case the aluminosilicate minerals (clay, feldspar, etc.) together with some dolomite are floated from the collophanite in column flotation cells with an amine in order to meet product specifications (31 % P205) (Service et al.). In other cases, such as the SF Phosphates Limited Mine, Vernal, Utah, the ore is treated by traditional fatty acid flotation of the collophanite with mechanical flotation cells (Weber, 1986). Preliminary tests have now been conducted to evaluate air-sparged hydrocyclone (ASH) technology for the flotation of western phosphate ore. For this preliminary study, samples were taken from the hydrosizer overflow stream (18-21 % P205) at the SF Phosphates Limited Plant in Vernal, Utah for scavenger flotation testing with the 2-inch ASH system in laboratories at the University of Utah. Selected design and operating variables are being studied, and the initial results show that satisfactory separations can be achieved by high-capacity ASH flotation at appropriate operating conditions. For example, with single-stage ASH flotation 80% recovery can be obtained with a scavenger concentrate grade of about 26% P2O5. These results are comparable to, or better than, those obtained at SF plant operations with conventional flotation cells and suggest that ASH flotation technology can be used to good advantage in the phosphate industry. Of course, research should be continued to consider other process streams, optimize the separation efficiency, and evaluate larger diameter ASH units.

Jan 1, 1993

By H. Fayed

Two-phase (water and air) flow in a self aerated WEMCO flotation machine has been investigated using computational fluid dynamics (CFD). A 0.8 m3 model is considered. The flow is modeled by Euler-Euler approach, and transport equations are solved using a commercial software ANSYS-CFX5 [1]. Because of the lack of circumferential periodicity in this machine, the entire machine is modeled and unsteady simulations are conducted in the whole volume of the bulb. Uniform bubble diameter is specified, and the effects of bubble diameter are determined by conducting simulations for three diameters of 0.5, 0.7, and 1.0 mm. The unsteady air flow rate through the machine is predicted as an outcome of the simulations. Air volume fraction contours and velocity field in different parts of the machine are presented and discussed.

Jan 1, 2012

By S. E. Phillipson

The Late Miocene San Cristobal Ag-Zn-Pb deposit represents syngenetic and epigenetic mineralization with low- and high-sulfidation characteristics. Geology is characterized by barren dacitic ring fracture domes, mineralized resurgent rhyodacite domes, strongly altered and mineralized tuffaceous lacustrine sedimentary rocks, and an extensive crystal-lithic tuff debris apron. The ore body is hosted by intra-cauldron sedimentary rocks and breccias. Fluid inclusions suggest that silver, lead, and zinc were transported as chloride complexes and precipitated by cooling in veins from <5 wt. % NaCl eq. fluids at 170°-215° C. Silver associated with resurgent rhyodacite was transported as a chloride complex and precipitated by increased H2S activity or increased fluid pH.

Jan 1, 2001

By William R. Yernberg

Most citizens take it for granted, but minerals produced in the mines of the western United States, including Colorado, are crucial to nation’s standard of living and quality of life, said Colorado’s Gov. Bill Owens in his welcoming remarks at the 106th National Western Mining Conference. The conference, which was organized by the Colorado Mining Association (CMA), was held Feb. 4-6, 2004, in Denver. Attendance was425, up substantially from last year’s meeting. The meeting included the CMA annual membership meeting as well as the CMA chairman’s and president’s reports. The meeting also included awards presentations in which companies were recognized for their efforts in pollution prevention, health and safety, and reclamation. The conference also included a tradeshow.

Jan 1, 2004

By R. B. Tippin

Great Salt Lake Minerals & Chemicals Corporation (GSL), a subsidiary of Gulf Resources & Chemical Corporation, is located on the east side of the Great Salt Lake, approximately 20 miles from Ogden, Utah. GSL processes brine from the north arm of the lake to produce potash, salt cake, salt and magnesium chloride brine. Potash fertilizer, in the form of K2SO4 is GSL&apos;s primary product. The GSL Sulfate of Potash Complex The GSL potash complex (depicted in Figure I) is divided into a solar evaporation pond system and the process plants. The solar,evaporation system consists of a 17,000-acre (68.8 Km2) ponding operation where the various salts deposit during the summer evaporation season, and a harvesting operation which recovers the deposits during the remainder of the year. The harvest is either preconcentrated in the flotation plant or processed directly in the chemical plant where sulfate of potash (SOP) is produced. The chemistry of the lake brine results in a solar deposit con¬taining primarily kainite (KCl-MgSO4.3H20), schoenite (K2SO4?MgSO4^ 6H2O), and halite (NaCI), with some carnallite (KCl.MgCl2.6H20) and epsomite (MgSO4.7H20). Other minor minerals may be deposited, depending upon the weather during the evaporation season. Each year, the solar deposit in the evaporation ponds will greatly depend upon the summer weather conditions, which have in the past proven to be quite unpredictable. Weather may alter both the quantity of the solar deposit and the composition of this deposit. During, a "short" evaporation season, the tonnage deposited decreases, but depending upon the short-term weather, the potash mineral content

Jan 1, 1977

By A. Acar, E. T. Tuzcu, Y. O. Vural

"In order to sustain the operations in chromite processing plants, due to concentrate selling cost, plants are in need of optimization in terms of capacity and recovery increase. In this study, DAMA Engineering carried out a methodological study for the purpose after a detailed sampling campaign in a plant which is situated in one the main chromite zones in Turkey; 1 The current status of the plant was investigated quantitatively with the bottlenecks, Plant overall efficiency in terms of recovery, Efficiencies of the particular equipment (mill, screen, gravity circuit), 2 A new circuit was proposed with the available equipment, 3 The new circuit that is product of modeling and experimental effort, was evaluated quantitatively as if it is a running plant, After 4-5 months continuous effort, the capacity of the plant was almost doubled (37 tph to 70 tph) and the plant overall recovery was increased from 48% to 63% by grinding adjustments and additional shaking tables theoretically. It was shown that the plant may move into profit with the minimum amount investment using readily available system. INTRODUCTION TO THE CURRENT PLANT The objective of the study is to increase the capacity and recovery of the chromite plant owned by Kurmel Group, Akmetal Inc. The complete study is given elsewhere (DAMA, 2016). The plant is situated in one of the main chromite zones in Turkey; Aladag. The current capacity of the plant is around 35 tph and the overall recovery declared by plant engineer is around 47 %. The chromite plant mainly has 3 units; crushing, grinding and gravitational circuits. The crushing circuit has 3 stages; a jaw crusher, a secondary cone crusher and a tertiary cone crusher operating in closed circuit with a vibrating screen with the aperture size of 15mm. In grinding circuit, a rod mill (2.44 6m x 3.6) and a ball mill (2.13 x 2.3m) are used for primary and secondary grinding, respectively. Derrick screens are used for the size separation. Additionally, for the size classification of the system, hydrosizers are used and each size fraction is sent to the shaking table sets. The middling product of the tables is subjected to re-grinding with a ball mill with the dimensions of 2.1 x 2.9 m. The capacity and the recovery are affected by several bottle necks; hydrosizers’ pure classification, primary/secondary mill power vs capacity problems, re-grinding product’s high slime content and so on. These combined factors made the plant to run in low recovery and capacity. Hence, DAMA was asked to make a study to investigate current status of the plant and propose a new solution to increase capacity and recovery of the plant. The conceptual flowsheet of the circuit is given in Figure 1 below."

Jan 1, 2017

By V. D. Smar

The flotation process may be considered an interactive system consisting of many chemical, operational, and equipment variables. Changing anyone of these variables causes an overall system response change. This study examines the effects of simultaneously changing the operating variables of: (1) frother concentration and air flow rate, and (2) frother concentration and collector concentration. It is part of a comprehensive study to look at how changes in several of the major variables may be used to produce interactions which will allow the rougher flotation process to be optimized. Ultimate recovery, flotation rate, concentrate grade and froth quality, are used as the major evaluative criteria.

Jan 1, 1993

By Sun Guangzhong, Liang Jinhuo

Adverse geological condition is a major factor which makes construction difficulty in tunneling. But if it is predicted and tunnel support is made efficiently in time, the above difficulty can be reduced. It is necessary to develop one or several effective and economical geological methods for prediction of tunnel geology while expensive and time-consuming instruments are used. This paper reviews and proposes several geological methods for prediction of fault, seam, contact zone, and groundwater inrush. These methods have been proved to be effective and economical in tunneling practice in China.

Jan 1, 1987

By S. Deming

Coal is China&apos;s main source of energy. In 1988, 76.1% of commercial energy consumption was supplied by coal. To provide a rational utilization of its coal resources, China has paid considerable attention to coal preparation over the last 10 years. In 1980, there were only 105 washeries treating about 100 million tonnes of coal, but by 1988 there were 151 washeries treating 171 million tonnes per year. This paper describes the development of China&apos;s coal preparation industry; its growth, the equipment, and the technology. Statistics and information on the current status of the industry are also be presented.

Jan 1, 1991

By V. O. Tenorio, A. M. Sanzana

"INTRODUCTION This report summarizes a research about mines which are transitioning from surface to underground mines. It is a guide to make strategic decision in these increasing amount of mines. Capital and operating costs are linked with major strategic decisions in the exploitation of an ore body. This is the reason to analyze costs related to this transitioning world trend. There are multiple reasons for transitioning from Open-Pit (OP) to Underground (UG) mining. The primary economic incentive for going UG is that the cost per unit of ore from OP mining eventually exceeds that from UG extraction. This is due to the excessive amount of waste that must be extracted when the depth of the pit increases. In addition, the reduced footprint of UG operations contributes to diminish the environmental impact on the surface. Furthermore, it becomes more difficult to find new, easily accessible ore deposits. Then, a cost model helps to guide strategic decisions in the transition from OP-to-UG mines. Objectives • Propose a methodology to guide strategic decisions in the transition from OP to UG mining. • Create an integrated cost model based on existing OP and UG individual cases. • Identify and characterize a group of mines transitioning from OP to UG. • Analyze operating and capital costs of a particular transitioning from OP to UG mine. MAIN CONCEPTS Open Pit Mining (OP) The main decisions in OP mines are: Cut-off grade, Stripping Ratio (SR), equipment size, stockpiling, pushback sequencing and processing capacity. The stripping ratio is measured as the tonnage of waste required to be removed to reach and extract one tonne of ore. The material extracted from an OP exploitation can be classified as waste and ore. This classification depends on the cut-off grade. The cut-off grade indicates the minimum amount of material with economic value in a block. The waste from the mine is going to the waste dump and the ore is going to stockpiles where will be store and then going to the processing plant (leaching or concentrator). The waste of this process is going to the tailing pond big pools. And the product is sell in the market. Another important issue is the mining capacity which is going to define the investment in mining equipment. Underground Mining (UG) The first decision to be made in order to open an underground mine is selecting the mining method. Caving methods are the more productive and have lower operating costs. There are three caving methods: Block Caving (BC), Panel Caving (BC) and Sublevel Caving (BC). The access development could be an horizontal adit or a straight or downspiral decline. A shaft could be used for inclined or vertical access. Other key issues are: equipment capacity, cut-off grade and production sequencing."

Jan 1, 2016

By Robert J. Collins

Computer-aided design drafting systems have been employed in plant design for nearly ten years. Current and future systems will include computer-aided engineering as well. This paper will explore the history and development of such systems including computer and workstation hardware, graphics software, and plant design applications software. The paper will also address future systems and will present both the system vendor and the mine mill designer&apos;s view. Specific examples of particularly successful applications will be included.

Jan 1, 1985

By George M. Potter

Under contractural arrangements with the Bureau of Mines, Mountain States Research and Development, Inc. (MSRD) completed a technological investigation to determine the feasibility of in situ mining of metal commodities other than copper and uranium, The study was based upon available literature and experience. The selection of potential candidates for in situ mining was influenced by economic importance, probable amenability to in situ methods, and environmental considerations. Four metals (or metal pairs) were chosen for feasibility studies: aluminum (with a copper byproduct), gold-silver, and manganese were recommended for further study and action; cobalt-nickel was also recommended contingent upon preliminary laboratory leaching and recovery investigations and field geohydrological work. Mining and recovery plans and an economic evaluation are included. Other metals with potential for in situ leaching are lead/ zinc, molybdenum, and vanadium.

Jan 1, 1981

By M. K. Eryadin, I. Yildirim, R. Asmatulu

Novel dewatering aids were tested on various coal samples from the U.S. and Canada in laboratory and pilot-scale filtration experiments. The reagents substantially improved the dewatering kinetics and reduced the cake moistures. The cake moistures were typically reduced from 20-30% by weight to 8-14% range in vacuum filtration. When the reagents were used in conjunction with a pressure filter, higher degrees of moisture reductions were achieved. In the present work, the novel dewatering aids were tested using different types of pilot-scale vacuum filters. The results were consistent with those obtained in laboratory experiments.

Jan 1, 2003

By Jan Wolf

The iron ore industry presently utilizes two types of de-posits. The first are the high grade deposits generally located in remote areas and, secondly, the low grade de-posits which are normally found nearer to the steel-making centers. The high grade deposits produce a direct shipping ore which has an iron content which may be close to the maxi-mum 70% of Fe. These deposits have reserves which are ex-pressed in billions of tons. The ore needs little or no up-grading and where this is performed is restricted to ore washing. With the large demand for iron ore pellets, plus a national drive to perform as much of the upgrading as possible in the native country, there is a trend to erecting pellet plants at the mine location~ Large iron ore suppliers such as Australia, Brazil, Venezuela and Liberia already have pellet plants in operation, and there are new plants projected or expansion projects under study. The low grade ores are mined at locations closer to steel mills such as in Minnesota, Michigan and Canada. These low grade ores require methods of beneficiation to obtain a commercially accept-able product with the modern beneficiation techniques it is no~, possible to produce iron ore pellets of 68% Fe and 4.5% silica from ores containing as low as 26% Fe. Figure 1 gives a general picture of the types of iron ores and their beneficiation. The final product of the high grade ore is a coarse concentrate, sinter product or pellets. The final product of the low grade ores is pellets and, in some cases, coarse concentrates.

Jan 1, 1971