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By M. Portal, L. Goicochea

This study is carried out in the Zenit mining concession, which is located in the city of San Pablo in the department of Cajamarca in Peru. The Project has 33 mineralized structures and according to laboratory analyzes we have the presence of gold and silver. The geostatistical evaluation provides an analysis on the distribution of precious metals in the vein. This information is used to improve the efficiency of metal extraction and to reduce costs. The general objective is to evaluate the polymetallic veins (Au and Ag), for which the classification of resources (measured, indicated, and inferred) has been carried out, taking into account the parameters of minimum distance from the composite, corresponding volume and tonnage calculation. In addition, an inventory of estimated geological resources was carried out with the block grades obtained to generate the tonnage-grade curves.

Feb 1, 2024

By J. C. Norman

The United States was the world’s largest producer and consumer of boron compounds during 1995. According to estimates from the US Geological Survey(USGS), boron mineral concentrate and chemical production in the United States totaled an estimated 1.1 Mt(1.2 million st) yielding 602 kt (663,000 st) of B2O3 for an estimated value of $462 million. This level of production exceeded 1994 revised production figures by about 9%. The United States continued to provide nearly all its own boron supply while maintaining a strong position as a source of sodium borate products and boric acid to foreign markets. During 1995, about 900 people worked in domestic boron mines and plants, about the same as in1994. USGS estimated total world production of boron during 1995 to be about 3 Mt (3.3 million st), yielding about 1.6 Mt (1.8 million st) of B2O3. World production in 1995 was about equal to revised 1994 levels.

Jan 1, 1996

By E. L. Reed

This paper addresses the state and federal permit- ting requirements and regulatory constraints associated with the development of new "grass roots" surface coal mines in the Western United States. Since a major portion of new coal development in the West will be on federally leased coal in Wyoming, my comments are directed towards that geographical area. This will give the reader some insight into the current regulatory framework within which western mining companies must operate-i.e., the major applicable state and federal laws and regulations, the more important state and federal regulatory agencies, and the major construction and operating permits that are required. Before discussing the impact of the regulations on our business, I would like to tell you something of my company and then briefly discuss Exxon's forecast of the long range outlook for coal. Carter Mining is an Won affiliated surface coal mining company. Exxon became interested in the coal business in the mid 1960's with the recognition of the future need for alternative fuel sources. Since that time, it has acquired coal reserves located in Wyoming, Montana, North Dakota, Arkansas, Texas, Illinois and West Virginia. Carter's first surface mine, the Rawhide Mine, located north of Gillette, Wyoming began production in August, 1977. Our second surface mine, Caballo, located just south of Gillette, began operating last October. We have a third block of federally leased coal just east of Gillette. By 1985 we anticipate Carter's western surface mines will be producing at an annual rate of 30 million tons, subject, of course, to successful market development efforts and regulatory considerations. Rawhide will ultimately have a permitted capacity of 24 MM tons per year. The coal at Rawhide is in two seams; one 80 feet in thickness and the other 20 feet (including a 6 to 10 foot parting). A large shovel is used to remove the overburden, and a similar shovel and dragline are used to mine the coal. Caballo has a 75 foot seam; otherwise it is similar in design and operation to the Rawhide Mine.

Jan 1, 1979

By J. A. Murray

Maintaining satisfactory air quality in electrowinning tankhouses is problematic and costly, particularly as plant operating current densities have increased. Conventional approaches have not proved completely effective. These include the use of beads, hollow spheres, surfactants and coalescer devices. They require powerful ventilation systems to be installed. As workplace and environmental regulations become more stringent, containment of the acid mist at its source is more attractive. An electrode cap system based on this approach has been developed and tested in two commercial copper electrowinning tankhouses.

Jan 1, 1996

By B. Whisner, A. Smith, J. Carr

"Electromagnetic based proximity detection systems (PDSs) are utilized on mining machinery to protect workers from being pinned or struck. These systems generate magnetic fields covering the space around a machine, and a miner-wearable component (MWC) detects the field. The PDS determines the distance of miners relative to the machine based on the detected magnetic flux density in the magnetic field. This information is used to establish warning and shutdown zones around the machine. Maintaining a stable magnetic field is essential for system accuracy. However, components used to generate magnetic fields can be influenced by temperature changes. Depending on ventilation conditions and seasonal alternation, a PDS can be subject to significant temperature fluctuation. To better understand and quantify this phenomenon, researchers from the National Institute for Occupational Safety and Health (NIOSH) developed an experimental apparatus to study the influence of temperature on magnetic field generator circuits used in PDSs. Results from the study show that the electric current through a generator can be influenced by both ambient and internal temperatures, modifying the magnetic field that is produced. These findings show that temperature can significantly influence the ability of PDSs, used in underground coal mines, to accurately determine a worker’s position in relation to mining machine. INTRODUCTION Electromagnetic based proximity detection systems have been developed to reduce machine-related accidents in underground coal mines. The first proximity detection systems installed in underground coal mines were developed for continuous mining machines (CMMs). There are five of such proximity detection systems that are approved for use in U.S. mines by the Mine Safety and Health Administration (MSHA) (Mine Safety and Health Administration, 2013; Mine Safety and Health Administration, 2015). There are several basic components that interact within an electromagnetic proximity detection system (PDS). A PDS includes two main elements: a set of generators to create magnetic fields around a CMM and a set of magnetic probes to detect the fields. These systems can determine if a miner is located at a safe distance from the machine based on the detected magnetic flux density. Stability of the magnetic fields is essential for system accuracy."

Jan 1, 2018

By A. L. Mular

A great deal of effort is being expended by mineral processing engineers to acquire a basic knowledge of modelling and optimization techniques. Stimuli such as immediate process improvement, expanded process understanding, optimal flowsheet design and re-design, and the development of new and better control systems are goals which excite the imagination in terms of increased profits. To reach these goals, process models and efficient optimization strategies, regardless of their purpose, assume an important role. Consequently, few of us can argue that such efforts are of no value. The purpose of this paper is to review empirical modelling methods and optimization strategies which appear to be of value to mineral engineers.

Jan 1, 1972

By K. Osseo-Asare

LIX63 in combination with DNNS selectively extracts nickel and/or cobalt from acidic leach liquors with pH values as low as 1.0. Nickel/cobalt and cobalt/nickel selectivities are achieved by varying the relative concentrations of LIX63 and DNNS. Increasing LIX63 concentration retards both extraction and strip-ping rates while DNNS has the opposite effect. Slope analyses of equilibrium data indicate that both LIX63 and DNNS are present in the extracted complexes. Examples of possible flowsheets are presented.

Jan 1, 1978

By R. N. Gow

Acidic treatment of enargite (Cu3AsS4) dissolves both arsenic and copper from the mineral and then attempts to separate them in the leach solution. The reactivity of enargite was examined in acidic solutions, over the pH range 1-7, to determine a potential range for co-dissolution.. Enargite mineral samples from Butte, MT and Quirivilca, Peru were used as working electrodes in a cyclic voltammetry corrosion cell setup, which were then cycled multiple times over -1000 to 1000 mV. Surface reactions and transitions were characterized using in-situ Raman spectroscopy, which were then compared to updated predominance diagrams for the copper-arsenic-sulfur system from a previous study done under alkaline conditions. The region of co-dissolution is limited to > 600 mV vs. SHE and pH < 1 under the proposed diagram.

Feb 23, 2014

By H. Huang, R. N. Gow

"EH-pH diagrams are useful tools in understanding how mineral surfaces react in solution and particularly how aqueous conditions can be changed to enhance mineral leaching processes. Successful application of these diagrams, however, requires that several considerations be kept in mind to prevent what had been termed as “gross errors” in their calculation and use. In this paper, the aqueous Cu-S system is used as the basis for explaining the mass-balanced method of calculating EH-pH diagrams with the STABCAL thermodynamic equilibrium software. A breakdown of the Gibbs’ Phase Rule and how it is used in STABCAL to modify the diagrams is included. The methodology was applied to the aqueous Cu-As-S system, and resulting diagrams were compared against examples of those generated using the predominant-ion method. The complexity of such diagrams increases with every additional component, and competition between species becomes more apparent, as can be seen by curvature in the resulting mass-balanced diagrams. The complete diagram for enargite (Cu3AsS4) is shown. It compares well with spectroelectrochemical measurements from Raman spectroscopy and cyclic voltammetry studies.IntroductionInnovation in the field of processing arsenicbearing copper ores has been of particular interest. Copper arsenic sulfosalt minerals such as enargite (Cu3AsS4) and tennanite (Cu12As4S13) are now frequently prevalent in ore bodies as the oxide and easily leachable sulfides become harder to find. These minerals, unless pretreated somehow, concentrate in copper sulfide flotation processes, in turn concentrating the arsenic levels. Increasing environmental restrictions on arsenic content for smelters makes the hydrometallurgical processing of these concentrates more favorable. While enargite is considered one of the more refractory copper sulfides, more so than chalcopyrite (CuFeS2), there are still several methods, both industrially proven and in development, that are capable of processing these ore types. Alkaline sulfide leaching can be used as a pretreatment method to solubilize arsenic selectively (Delfini et al., 2003; Anderson and Twidwell, 2008; Tongamp, Takasaki and Shibayama, 2010a, 2010b), or the entire metal content can be leached using acid-type leaches such as acidified ferric sulfate (Dutrizac, 1981; Hackl et al., 1995; Klauber, 2008), or the chloride assisted, CESL (McDonald and Muir, 2007) or nitrogen species catalyzed (Anderson, 2003) processes can be used.As development of these leaching technologies proceed, it is also important to develop an understanding of the mineral thermodynamics. To date, there are numerous studies on the Cu-Fe-S-H2O system, particularly as it relates to chalcopyrite leaching, yet few studies have done on the Cu-As-S-H2O system. Computer-generated EH-pH diagrams have been employed to illustrate the importance of thermodynamic calculations in providing insight into such a system."

Jan 1, 2016

By Raymond L. Lowrie

Deregulation, as authorized by the Energy Policy Act of 1992 (PL102-486) allows free-market competition in the electric-utility industry. As the act unfolds, though, uncertainties abound about the type, degree and direction of impacts throughout the affected economy — from fuel suppliers to electricity generators and from power distributors to energy consumers. Instead of having a familiar base of captive customers and electricity prices fixed by negotiation with state public utility commissions, utility companies are preparing for open, free-market competition. They are looking at all areas, including fuel supply, to cut costs to remain competitive. Humorous anecdotes are told about utility companies shunning insiders for senior executive positions. Instead, they are opting for people from the telephone or other industries with deregulation experience. And there are light-hearted stories about a trend away from traditional electric-company names, such as the name of a city or state followed by Edison or Power and Light, to space-age names, such as Ameren, Entergy, Illinova or Unicom. No one wants to be left behind or be perceived to be left behind.

Jan 1, 1996

By C. L. Wilsey, K. M. Oakes, W. J. Reich, M. J. Protani

The time frame required to complete the National Environmental Policy Act (NEPA) process for a new mine, or for the expansion of an existing mine, can range between 9 months to 24 months, or more. The time frame will vary depending on whether an Environmental Assessment (EA) or an Environmental Impact Statement (EIS) will be completed. Completing properly designed baseline studies to collect natural resource data to support the EA or EIS prior to the start of the NEPA process can shorten this time frame. The two year natural resource baseline study completed by Homestake Mining Company for the Ruby Hill Mine, located in Eureka County, Nevada will be used as the case study to describe how properly designed and executed natural resource baseline studies streamlined the NEPA process.

Jan 1, 2001

By Ben V. Petersen

Surveying is to tunneling, as a steering wheel is to a car—somewhat essential if you want to end up in the right place. The principles of tunnel surveying have remained unchanged since the first tunnels were constructed: To mathematically connect the selected start and end points of a tunnel and physically translate that alignment onto the ground. The alternative is just dead-reckoning and leaves the probably less than satisfying end results to chance. Today’s laser-guided tunnels often have to thread the needle through a maze of soil types, utilities, structural features and other underground considerations. Surveying makes it possible.

Jan 1, 2005

By A. Bhattacherjee

Industries in general and the mining industry in particular have become more safe than ever before. However, there is a need to increase the search for the causes of mining work-related injuries and to contribute to their reduction through job design, work procedures, and worker training. Mine accident and hazard control has to be practiced in a manner which is consistent with the overall objectives of the mine management, among which are the optimum allocation and effective utilization of the resources. The purposes of this paper are to (i) review the role risk analysis in safety management with references from mining and other industries; (ii) discuss the risk measures appropriate for injury analysis; (iii) present a set of analytical tools to injury experience data in under-ground coal mines; (i v) apply these tools on case study example; (v) discuss the results of the case study; and (vi) amplify the application limitations and the future research needs.

Jan 1, 1991

By ?. ?ivkovic

The silicate slag and copper matte that are the byproducts of smelting copper in a reverberatory furnace contain SiO2, FeO, Fe3O4, CaO and Al2O3, and Cu, Fe and S, respectively. These components influence the oxide (Cuox), sulfide (Cusul) and total (Cutotal) copper content lost in the waste slag. This paper uses multiple linear regression analysis (MLRA) to determine the degree of influence. The results of calculations obtained using MLRA were compared to actual measured results and found to have a large degree of correspondence, with the coefficient of determination R2 = 0.975. These results indicate that slag composition and copper content in the matte influence the copper losses in the waste slag with a probability of above 97%. It was determined that, of the total copper content of the slag, 74% is in sulfide and 26% in oxide form, and that this ratio is not dependent on the slag or matte composition.

Jan 1, 2010

By R. D. Williams

Several hydrometallurgical leach processes have been recently proposed for the recovery of copper from copper concentrates. These include the Cymet Process of Cypress Metallurgical Processes Corporation, the Arbiter Process of the Anaconda Company, and the Treadwell Process of Treadwell Engineering company(1). These processes and similar processes for recovery of other minerals, have several phenomenological similarities which make their quantitative description difficult at best. These include (a) the presence of more than one phase, (b) non-uniform mineralization of the feed concentrate, (c) surface and diffusional effects, and (d) a particle size distribution which varies with time. Semi-theoretical, rather than purely empirical, treatment of such processes in their developmental stages will result in a better understanding of the physico-chemical mechanisms in effect. This, in turn, will allow reliable process designs to be made on reasonable time scales for reasonable development costs. Once a production unit is built, such an approach will provide straightforward methods for process control and optimization. A research and development effort to determine criteria and procedures for semi- theoretically characterizing such mineral leach recovery processes has been initiated in a joint venture by the Arizona Bureau of Mines and the College of Mines at the University of Arizona. This group has as its task the mathematical characterization of hydrometallurgical leach recovery processes using semi- theoretical mechanisms for the underlying phenomena. The resulting models are experimentally verified and parameterized on the laboratory scale in such a way that they can be utilized with similarity criteria to provide reliable scaleup to production designs. This discussion will be centered around the elements of such an approach and how they fit together.

Jan 1, 1975

By Earle Faig

Earle Faig Along with other transportation modes, the barge industry will be greatly affected by trends in domestic coal production. Traditionally, coal has been one of the major commodities moved by barge. Now, because of events in the international energy market, coal is finally getting the recognition it deserves as a major component of the country&apos;s energy program. Perhaps even more significantly, a series of events has caused other countries to turn to the United States as a source of coal. Although the outlook for coal demand is optimistic, it will be greatly influenced by the ability of the transportation sector to handle the additional traffic. Because of its long experience in moving large quantities of coal, the barging industry is in an excellent position to capitalize on coal&apos;s increased popularity. A brief description of the barging industry should facilitate the discussion of coal as it relates to that industry. Barge companies operate on a river system that is over 40 Mm (25,000 miles) long. It includes the East and West Coasts and the Mississippi River System comprised by the Allegheny, Monongahela, Kanawha, Ohio, Illinois, Missouri, Tennessee, Cumberland, Arkansas, Warrior-Tombigbee, and Mobile Rivers, and some smaller tributaries. The Gulf Intracoastal Waterway stretching along the Gulf Coast from Brownsville, TX, to Apalachicola, FL, also is considered part of the inland waterway system. Approximately 1,800 companies operate on the inland river system and have a combined fleet of about 4,400 towboats and 28,000 barges. The fleet of towboats represents 4.8 GW (6.4 million hp) of power. The towboats comprising this fleet vary in size from a small harbor boat to a large line haul boat with 7.5 MW (10,000 hp) of power. The choice of size and power of the boat depends on a number of factors, including the size of the river and operational constraints, such as lock size, river-current rate, and water level. The choice also depends on the tow size. A single tow on a river capable of locking through 15 barges at a time handles up to almost 20 kt (22,000 st), whereas a tow on the lower Mississippi, which has no locks, can accommodate up to 41 kt (45,000 st) of cargo. Because the quality of coal is not typically damaged by exposure to the elements, it is usually moved in open hopper barges, although covered barges are used occasionally. The most frequently used size is the jumbo barge that measures 59 m (195 ft) long by 11 m (35 ft) wide by 4 m (12 ft) deep and can handle up to 1.4 kt (1,500 st) of coal. Advantages of Barge Transportation Barging offers several inherent advantages in transportation of bulk commodities like coal. First, barges can carry large quantities of product. A single jumbo hopper barge can handle 1.4 kt (1,500 st) of cargo while it takes 15 91-t (100-st) capacity rail cars or 57 trucks hauling 24 t (26 st) each to move an equivalent amount of cargo. Thus, barges can move more tonnage with less equipment than competing forms of transportation. Second, barging offers the most fuel efficient means of transportation. Less energy is required to push a load over water than to pull a similar load over land. The amount of pollution attributable to barge traffic is minimal because barges consume less fuel. Third, barging is an inexpensive form of transportation. The inland waterway industry transports about 12% of the nation&apos;s freight for about 2% of the total freight bill. This can be attributed to competition between the large number of companies on the river system and competition with other transportation modes. Fourth, barging is an environmentally safe method of transportation. Inland river routes expose fewer urban areas to hazardous substances than rail or truck. And barge spills occur less frequently than rail or truck spills. The industry does pose some disadvantages. The waterway system is constrained by the natural river network, so barges cannot travel on the most direct straight-line route. This means that barging is usually an incomplete form of transportation requiring interface with truck or rail. The industry&apos;s market is limited to those geographical areas that are located on or near the rivers. In addition, it is a time-consuming transportation mode, making it impractical for many types of commodities.

Jan 10, 1982

By V. Dentoni

The paper deals with the assessment of the visual impact generated by surface mining and quarrying. Previous research works proved the applicability of an indirect method based on the elaboration of digital images through which the extent of the visible altered area and the chromatic contrast with the surrounding environment is calculated. The resulting level of visual impact allows an objective comparison among different cases as far as the evaluation procedure is univocally defined. The article illustrates the application of the method to a number of selected quarries located within the Sardinian territory; different issues are discussed such as the choice of the viewpoints from which the pictures are taken, the influence of the distance from the quarry to the selected viewpoints, the light condition and the orientation of the quarry faces. Moreover, the visual impact level obtained from pictures taken at the same time with five digital cameras are compared in order to evaluate the contribution on the overall uncertainty.

Jan 1, 2008

By R. L. Grayson

Using powerful database management software, nested-field analysis and microanalysis of narratives have been made of West Virginia accident data, resulting in a new approach for targeting and prioritizing safety interventions by county, mine size, specific mine, job title, type injury, etc. and combinations of these parameters. The analyses have been useful in focusing training and discussion sessions on specific work problems, trends, conditions, and situations for targeted groups of miners. Application of the technique will be presented in this paper, along with comparisons of various mine performance measures.

Jan 1, 1997

By R. Karl Zipf

Highwall mining is an important surface coal mining method, and it may account for approximately 4% of total U.S. coal production. Highwall stability is the major ground control related safety concern. Ground control plans for highwall mining should specify hole width, web pillar width, barrier pillar width and number of holes between barriers. This paper offers simple design charts for these parameters aimed at providing “ball park” checks. Web pillars containing pre-existing auger holes are analyzed and a design chart for estimating their minimum width is also presented. Finally, close proximity multiple seam highwall mining, which may have caused several serious highwall failures, is analyzed. Web and barrier pillar recommendations for this special situation are presented.

Jan 1, 2005

By Wayne W. Murdy

Peru is a mineral hot spot in the world today. Newmont is in the exploratory phase of this mining cycle, a phase full of optimism and expectations. But exploration is high risk. There will be successes but also failures. Many foreign companies will come and go. But it is the responsibility of the mining industry leadership of Peru and the government to continue to foster an environment conducive to investment. This is the time of year companies begin planning their next annual report. Last year, Newmont’s was called “new horizons.” It highlighted the company’s global expansion into Peru, Uzbekistan and Indonesia. Now, projects that were only on the horizon a year ago are moving into production. So “turning opportunity into gold” may be this year’s theme.

Jan 1, 1996