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By Christof Brewka

Los Pelambres, 200 km north of Santiago, Chile, is the latest in a series of mega-projects developed in this part of the world. While most of its predecessors are spread over open desert, the Los Pelambres mine is nestled inside a narrow alpine valley high in the Andean Mountains. To handle the daunting task of transporting the mined copper ore more than 12 km and 1,400 vertical meters downhill to the concentrator plant, a gigantic belt conveyor system (capacity of 8700 mtph, 1800 mm wide ST 7800 steel cord belt, 2.5m diameter pulleys, an elaborate braking system including a mechanical failsafe and large reducers with a total installed drive power of 25,000 kW) has been employed. Many of these components have pushed the limits of conventional belt conveyor design.

Jan 1, 2000

By Arthur W. T. Grimley

Hydraulic coal mining is being successfully practiced in China, U.S.S.R., Japan and Canada and in each country, excepting Japan where suitable sites are not available, the system is being expanded to either existing conventional mines or new mines. Productivity levels and economics at these mines are in all cases better than the productivities achieved in conventional mines in the same general localities. In the U.S.S.R. face productivities approaching 50 tons per man shift have been reported while in Canada the latest statistics show average face area productivity levels are in the region of 200 tons per man shift production monitor. In the United States hydraulic mining has not been actively pursued to the same degree and consequently there are no full scale hydraulic coal mines in operation or construction. Because many of the coal measures in the Western U.S.A. are generally somewhat similar to those being successfully hydraulic mined in Western Canada and parts of Siberia it is realistic to believe that successful hydraulic mines can be designed and developed in the Western U.S.A. Particularly if the vast technological base that already exists is used to improve on other people's ideas, systems, methods and equipment.

Jan 1, 1983

By David L. Giles

The Lime Creek* ore body in northwestern British Columbia is one of the few commercial primary stockwork-type molybdenite deposits in North America. Others include the Climax, Urad-Henderson, Questa, and Endako ore bodies. They are mined on a low grade-high tonnage basis, and are open pit operations except for Climax and Urad-Henderson. Much recent geochemical research on both porphyry copper and stockwork MoS2 deposits has been concerned with dating of micas related to the mineralization and associated igneous rocks. The results appear to show that mineralization and the predominant magmatic events of the deposit are indistinguishable in age (1-5), except where dating has been in sufficient detail to resolve the analytical overlap (6). At Lime Creek, geologic information shows that the Main granodiorite, the major intrusive and dominant host rock for MoS2 mineralization, was emplaced and had solidified sometime prior to the introduction of MoS2. The first MoS2 episode is intimately related to localized bodies of kalialaskite which clearly intrude the older stock. K-Ar dating was undertaken to clarify the age relations between Lime Creek plutonism and the apparently younger hydrothermal event that began with kalialaskite.

Jan 1, 1975

By Allan D. Fernie

Growing interest in pit crushing and conveying is evident from the many articles, technical papers, and new equipment development recently presented. Application of a pit crushing and conveying system is complex, as many factors such as mine design, production scheduling as well as initial and ongoing capital and operating costs must be thoroughly and realistically examined. This paper will address the fundamentals to be considered and review several approaches to developing a total system for a new and existing mine situation. The planning function will be outlined and operating and design criteria defined to interface the mining operation and the pit crushing conveying system.

Jan 1, 1983

By B. J. Huls

The commissioning of a Distributed Digital Control. System for the grinding circuit at Cuajone, was completed by mid August, 1985. Development of a successful strategy, excellent operator acceptability and the visual aspects offered by the display of the central console, improved mill throughput significantly. The inherent features of a digital system enhanced the flexibility in grinding control and allowed the mills and classifiers to be operated at maximum capacity. This paper discusses in detail the strategy development, the production restrictions encountered, and evaluates the overall performance of the digital control system. 1.0 Introduction In November 1976, the Cuajone Concentrator, located on the western slope of the Andes in Southern Peru, was commissioned to treat a nominal 41,000 TPD of ore. A systematic elimination of production restrictions has resulted in a continual increase of concentrator throughput to 48,700 TPD before the grinding control was in- stalled.

Jan 1, 1986

By J. S. Whatley

The properties, origin and industrial uses of kaolin clay are briefly reviewed. The general waterwashed beneficiation process is described. Yost aspects of filtration and solids-liquid separation as practiced in the kaolin industry are mentioned along with devices that are currently in the developmental stage. The paper focuses heavily on the well known art of rotary vacuum filtration, including general construction and operating details. Devices under investigation that might be used to mechanically or electrically dewater clay slurries to higher cake solids levels than can be achieved with rotary vacuum filters are described briefly.

Jan 1, 1986

By Joseph W. Mussey

Bio-epigenetic sulphur deposits occur in Pecos, Reeves and Culberson Counties of far West Texas. Sulfate reducrng bacteria, utilizing hydrocarbons as energy, transformed gypsum into replacement limestone and hydrogen sulfide. Hydrogen sulfide, retained in the porosities of the replacement limestone, was subsequently oxidized by highly oxygenated groundwaters, and native sulphur precipitated. West Texas sulphur was first recognized at surface exposures by William P. Blake, a geologist attached to the Captain Pope Military/ Scientific Expedition of 1854. Attempts were made in the early 1900's to mine these sulphur vent exposures by a retort method, but the ventures met with little success. In 1967, Duval discovered a large sulphur deposit near some of the old sulphur works in Culberson County. Duval also extended a small sulphur deposit in Pecos County. The Frasch process, developed for producing sulphur from Gulf Coast salt domes, proved successful in West Texas type sulphur deposits also. However, modifications of the process were necessary to provide economical and efficient sulphur recovery from the varied ore modes. West Texas conditions and logistics require the ultimate in productivity to be competitive in the domestic and foreign sulphur markets. Several companies, in addition to Duval, are producing or have produced sulphur in West Texas. As of the first of June 1984, a total of 29.4 million long tons of sulphur had been produced west of the Pecos -aver. Duval produced more than 88 percent of that total.

Jan 1, 1984

By B. M. Flohr

Railroads are cost competitive with trucks for hauls greater than 500 miles - WRONG. Today I will tell you about many rail movements of less than 100 miles throughout the country. Rail is a short haul transportation alternative you must consider. Transportation today is the largest controllable cost in the total cost of production of goods. In fact it is the one cost area where aggressive management, using new tools, can achieve significant reductions. You can't control the price of metals in the world market, you can't control labor rates since they are tied to industry norms, and the price of raw materials are relatively insensitive to specific price reductions to your firm. Transportation is the one area where major savings are now being realized. Sample Movements First, I will give you several examples of short haul rail moves to make you a believer that they do exist. Then I will show you the reasons why railroads suddenly "like" short hauls.

Jan 1, 1986

By B. Berhe, R. D. Lawrence, J. Hinzer

"The fortunes of mining companies and their implied value are tied to cycles - both economic and commodity – within which they operate. Hence the determination of appropriate future metal prices is one of the most critical factors faced by mineral valuators especially for advanced projects. Price, and hence revenue, is usually the most sensitive input to the valuation model. Empirical studies of past forecasts show that the success rate for commodity price forecasting is very poor. This paper explores various approaches and comments on their strengths and weaknesses. We conclude that careful evaluation of long-term metal prices is a key element and is hardly a luxury that can be left to simple averages or rules of thumb. INTRODUCTION Discounted Cash Flow (""DCF"") analysis, is well suited for the valuation of advanced mineral development assets, for which there are identified mineral resources and some form of economic assessment (Pre-Feasibility or Feasibility Study). The DCF method is also the most commonly used method for determining value for such assets. It provides a means of relating the magnitude of expected future cash flows from profits (or losses) to the magnitude of the initial cash flow (investment) needed for capital expenditures to purchase or to develop an asset for commercial production. The method proves useful in making investment decisions as it allows for the quantification of the Net Present Value (“NPV”), as well as the Internal Rate of Return (IRR) and Payback Period on initial investment capital. Valuation by its very nature is a forward-looking exercise. The DCF method attempts to estimate the NPV of expected future cash flows, by selecting factors that will likely affect future cash flow based on informed analysis. One of the most critical and sensitive factors is the determination of appropriate future commodity prices. “The variables that have the greatest impact on a DCF evaluation are the reserves, the metal prices, and the discount rate.”1 The determination of future commodity prices for valuation purpose or during M&A negotiations is a hotly contested issue. There are a number of analysts, institutions and specialized commercial data suppliers that provide both short and long-term commodities price forecasts. Also, the use of an aggregated mean for all available forecasts, or consensus forecasted prices for valuation purposes is not uncommon. The methods used in making forecasts for each forecaster may vary and in many cases may not be publically disclosed. Nonetheless, the aggregated mean of all forecasted commodity prices of reputed institutions is usually taken to “represent the market’s view of likely future commodity prices.”"

Jan 1, 2016

By D. Spitty

Mining companies often have many disparate systems and repositories of data in their organization for planning and scheduling outbound mining supply chains. To optimize ore quality, throughput, transport logistics scheduling and delivery to contract, planning teams need to model and manage the value chain accurately and achieve a consolidated, enterprise view of operational performance. Planning teams coordinate a complex series of activities to ensure production forecast accuracy. They also negotiate and execute complex contracts often with disconnected and limited visibility of production forecasts, quality, and variability with little ability to accurately market potential product specifications over longer time horizons. This market is becoming increasingly dynamic, with increasing variability and the time for planning teams to react is decreasing. This is driving the need towards using science to generate the necessary scenarios required to support the decisions made by planners on a frequent basis. Resource-to-Market is a highly flexible, user-configurable supply chain management system for the mining and metal processing industries. This provides an integrated view of the supply chain that supports the dynamic nature of planning in a mining company, embraces variability of elements across the supply chain with the ability to optimize across all the functional areas of the operation to enable optimal decision making for often competing objectives such as throughput, quality, cost, revenue and profit.

Feb 23, 2014

By V. de Macedo Torres

There are technical and commercial limitations on using high fluorine copper concentrates in industrial copper smelters. The presence of more than 1000 ppm of fluorine in copper concentrates affects the sulfuric acid units generally integrated to copper smelters, and penalties are normally applied to high fluorine concentrate prices. Several process alternatives to this issue were studied at CVRD Technology Center (SUTEC): modifications on conventional sulfuric acid plants to use high fluorine concentrates, removal of fluorine containing minerals in flotation using depressants, selective leaching of fluorine minerals and sulfuric leach of copper concentrates. Finally, a hydrometallurgical process of removing fluorine was developed by SUTEC.

Jan 1, 1997

By J. P. Baur

The sensitivity of radiochemical techniques makes possible the study of the initial stage sulfuric acid leaching kinetics of chalcopyrite and other copper sulfide minerals. High-grade Transvaal chalcopyrite was neutron irradiated in a TRIGA reactor to produce radioisotopes copper-64, iron-59, and sulfur-35. Dissolution rates were measured in the time interval zero to 60 minutes during which time significant anomalies were observed. First, an initial period of rapid dissolution lasting a few minutes; second, an arrest or "plateau" region usually lasting from 6 to 10 minutes; third, a second period of dissolution of lesser rate than the first. The effect of solution variables such as pH, oxygen partial pressure, and ferric ion concentration at different temperatures were measured. The initial rate data were correlated by considering the rapid reaction to be due to the dissolution of surface oxidation products or the formation of an iron depleted surface layer. The data for the second slower reaction have been explained to be due

Jan 1, 1972

By Bruce Watzman

"Few issues are more important to the National Mining Association (NMA), the U.S. mining industry and NMA’s MINExpo International 2016 exhibitors than safety.Global mining safety and health is a journey necessitating continuous improvement, collaboration and innovation on the part of both mining operators and their suppliers.MINExpo 2016, which takes place Sept. 26- 28, 2016, in Las Vegas, provides attendees with the opportunity to view technologies to help refine management of mining safety and health, utilizing NMA’s CORESafety system. CORESafety ‘One of the best’Launched by NMA in 2011 and moving forward ever since, CORESafety is driving continuous improvement in safety and health performance among participating industry companies by shifting from a command-andcontrol regulatory approach to a risk-based systems approach built on the Plan-Do-Check-Act model (Fig. 1).Considered an exemplary safety and health management system, NMA’s CORESafety system helps mining operators change their approach to safety and health management by enhancing the safety and health culture throughout their organizations. Although it is challenging to consistently and completely control all the factors and variables occurring in daily mining operations, experience has shown that applying systematic controls to as many variables as possible is the most successful approach for improvement in mining safety and health.When embarking upon the development of the CORESafety framework, NMA’s leadership set an ambitious goal to eliminate fatalities and reduce the injury rate 50 percent in five years, or the “0-50-5” goal. While the goal has not been met yet, the steady progress has been extraordinary with fatalities among participating companies dropping 45 percent during the period 2011-2015 (Fig. 2). Data also demonstrate that, as participating companies increase their level of implementation, total injury rates have also declined (Fig. 3).In a September 2015 interview with NMA, Penn State University mining engineering Professor Jeffrey Kohler praised CORESafety as “an inspired and timely program that brings together key elements to achieve safety and health goals.”"

Sep 1, 2016

By Ernst P. Hall

As a scientist and an engineer whose responsibilities include the consideration of air pollution and its control, I am frequently called upon to answer variations of two basic questions, These questions may I be set forth as: (1) How much air pollution does the coal industry cause? (2) How serious is the air pollution problem to the coal industry? At first these questions may seem elementary and almost trite, but serious consideration of them will show that they are technologically involved and I further complicated by the subjective base to which they must be evaluated.

Jan 1, 1963

By Leonard Sugin

As we approach the end-of the 20th century we are made more aware of the tremendous role that energy plays both directly and indirectly in our varied way of life. The industralized nations of the world have already established industries and economies which are greatly dependent upon the availability of energy. The underdeveloped and developing nations of the world are slowly and surely moving to the same utlimate requirements. The world wide need for distribution of energy sources is continuing to grow. At the present time there is a great imbalance between the sources of energy and the consuming economies In order to bring about greater equality between supply and demand major efforts and large capital expenditures are constantly being made. Industralized areas are seeking their own independent sources of energy whereas those areas of the world which contain great reserves of energy are limiting its export as well as developing its own industralized capacity. Nevertheless, energy bearing materials are still transported great distances in order to satiate the appetites of power hungry economies.

Jan 1, 1975

By Keith G. Wallace

In 1982 the U.S. Congress passed the Nuclear Waste Policy Act (NWPA) to provide for the development of an underground repository for spent nuclear fuel. This development will be managed by the United States Department of Energy. In 1986, the President selected three areas for site characterization to determine their suitability for the development of an underground repository; those sites were: 1) A site in volcanic tuff located at Yucca Mountain in Nevada, 2) a site in bedded salt located in Deaf Smith County in Texas, and 3) a site in basalt located in Hanford, Washington. At present conceptual repository designs are being developed for each site. A key element of a repository design is the underground ventilation system required to support construction, nuclear waste emplacement, and potential waste retrieval. This paper describes the preliminary ventilation system designed for the repository in tuff. The concept provides separate ventilation systems for the construction and waste emplacement activities. The paper further describes the means by which acceptable environmental conditions will be re-established to allow re-entry into previously closed rooms for the purpose of inspection, maintenance or retrieval.

Jan 1, 1987

By Douglas M. Dwosh

INLAND STEEL COAL COMPANY'S experience with a gypsum cement, with and without fiber glass filler, indicates that the concept of utilizing standard rock dust equipment to dry handle and apply gypsum cement as a mine sealant is feasible, simple and economical. Prior to 1975, Inland had casually experimented with a few sealants and had discussed the advantages and shortcomings of other sealants with various users. Hower in mid-1975, Inland foresaw the need to seriously acquire a practical sealant system. There were nearly a dozen sealant materials on the market at that time: silicate-based materials, Portland cements, vermiculite cements, gypsum cements, and magnesium-oxysulfate cements, each with their own fillers and additives. The applicating equipment ranged from simple to complex: wet mix or slurry machines operating on either a batch or continuous basis, high viscosity pumps, and pneumatic, dry conveying machines with water nozzles. Compounding the selection process, two or more products could often be used with the same machine, or a given material could be successfully applied with more than one type of machine.

Jan 1, 1976

By John Hickey

Management teams at mining companies begin to ask themselves whether to take a company public and, if so, how to do it as they approach the normal threshold for going public in terms of revenue and operating performance. Today, the expense of going public generally suggests the company has at least $20 million in annual revenue and at least $2 million in cash. The revenue number can be lower for mining companies with large reserves. In order to properly attract the investing public, the company must also be operationally strong with robust prospects. The company should have a strong management team and a consistent history of double-digit growth that will continue into the foreseeable future. Assuming the thresholds are met, a company?s management needs to weigh the pros and cons of going public.

Jan 1, 2012

By G. Bonifazi

The study of minero-petrographical characteristics and the subsequent textural and structural characterization of an ore mineral represents the first step of each industrial processing whose aim is the beneficiation of each valuable mineral phase present inside the ore. Analytical, mineralogical and petrographical, chemical and multispectral image analyses based investigations, applied to eclogitic ore samples deriving form "in situ" sampling campaigns, were applied. These procedures enabled to point out some textural and structural aspects characteristics of ore litotypes belonging to eclogitic-amphibolitic dikes. Such dikes are characterized by a paragenesis constituted mainly by siliceous gangue and accessory "useful titanium minerals" as rutile [TiO2], "pseudolilmenite", ilmenite [FeTiO3] and sphene [CaTiSiO5]. In the beneficiation process applied to ore s is of preliminary importance to establish a strategy in order to obtain a recovery of high quality "mono-minerals concentrates" as rutile, "pseudolimenite", ilmenite and phene. To reach this goal is thus necessary to develop a preliminary study of the textural, structural, petrochemical and minerochemical characteristics of the samples. Different ore samples (eclogitic rocks), resulting from sampling campaigns carried out in the Piampaludo area (Sassello district: Savona, Northern Italy), are examined.

Jan 1, 1994

By Edward A. Vitunac

The emerging importance of pneumatic conveying systems for bulk materials is becoming recognized by more persons responsible for materials management as consultants, at the corporate level and at the plant level. They have learned that the economic advantages of a pneumatic system are frequently decisive when compared to alternate methods. Included in these advantages are relative simplicity, ease of installation, flexibility, ease of maintenance, cleanliness, safety and ease of automation to the degree desired. In general, installed costs favor a pneumatic system when compared to competing mechanical systems if the transporting distances are long or to and from many points. In addition, supplemental use such as cooling, heating, or drying may supply the incremental value required to justify its selection. (1). The main disadvantages of a pneumatic system is the greater horsepower required per unit weight of material conveyed and material limits in abrasiveness and density. In addition, there is a tendency to increase material breakage at changes of direction and at any obstruction such as the imperfect butting of one, piece of pipe to another in the conveying line. Classification of the material at the discharge may also cause problems in dusting and segregation. Materials weighing less than 4 pounds per cubic foot tend to cause feeding and collecting problems although they can be conveyed easily. Material between 4 and 20 pounds per cubic foot can be handled with less problems but flow rate is hard to predict. The 20 to 60 pounds per cubic foot range offers best results; whereas, over 60 pounds per cubic foot, materials tend to drop out of the air stream and settle in the pipe line unless careful provisions are made to prevent it. (2).

Jan 1, 1967