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By J. A. Herbst, R. Zaragoza

Conventional control schemes in use today are not able to produce satisfactory control when high-frequency disturbances are present in the flotation feed. An advanced model-based control scheme is presented here as a promising solution to this control problem. The main feature of this control scheme is the real time identification of the unknown disturbances in the first few cells of the flotation circuit. This information is used to control the rest of the flotation plant in a feedforward fashion. This control scheme also provides flexibility to meet any metallurgical, economical, or management objective.

Jan 1, 1987

By Stephen Hoffman

The Environmental Protection Agency (EPA) is investigating approaches to control non-coal mining wastes. In May 1988, the EPA's Office of Solid Waste (OSW) released a document that outlined an approach to manage non-coal mining wastes and materials. This document was called Strawman I. It was a staff-level approach designed to aid the continued participation of interested parties and to enhance EPA's understanding of mining waste issues. EPA has been working with states, public interest groups and the mining industry to gather information and to solicit input on waste management approaches. The involvement of the states in the Strawman process has been coordinated by the Mine Waste Task Force of the Western Governors' Association and the Interstate Mining Compact Commission. Involvement of public interest groups has been coordinated through Colorado Trout Unlimited. And the participation of the mining industry has been managed principally by the American Mining Congress. In May 1990, EPA released Strawman II. It was based on comments submitted to the EPA on Strawman I and on information given to the EPA by interested parties since 1988. Strawman II is again a staff-level approach to protect human health and the environment from wastes and other materials associated with non-coal mining. In September 1990, meetings were held with public interest groups and the mining industry to discuss their comments on Strawman II. By early 1991, the EPA expects to make a decision on how to proceed with program development.

Jan 1, 1990

By Gary Buchan

During several months in 1996 and 1997, Cyprus Twentymile Coal Co. (TCC) set world production records at its Twentymile Mine in northwestern Colorado. These records were due to the company's implementation of a state-of-the-art longwall mining and conveyance system along with a -highly dedicated work force. This article is a case study of the design of long panels at the mine from conception to implementation. Obstacles that needed to be overcome included subsidence engineering, environmental regulations, conveyance, ventilation, equipment design and continuous miner (CM) development timing.

Jan 1, 1998

By Ahmet Unal

Inexpensive and effective means of delivering courses to mining engineers who live at remote and scattered locations remains to be a challenging issue. Computer-based instructorless but interactive multimedia delivery is a good substitute to traditional short courses and one-way broadcasts. Such a system, enhanced with a wide area network, is an inexpensive alternative to two-way broadcasts and even to a traditional university. Course material can either be delivered on compact disks (CDs) or on-line from the host servers over the phone lines using a personal computer and a modem. Although technically not feasible using ordinary telephone service lines at the present time without further modification, advances in this field indicate that this up and coming medium may dominate the competition in the future. This paper investigates the present and the future of this technology and discusses the experiences gained in creating and disseminating a prototype multimedia CD which was created at the Rock Mechanics and Explosives Research Institute of the University of Missouri-Rolla to teach a portion of a course in Ground Control. The hardware and software used in creating the audio, 3-0 graphics, animation dips, video clips, and movies are listed. The structure of the program and the way how interactivity was achieved is explained in detail.

Jan 1, 1996

By Michael J. Sapko, Robert A. Cortese

A flame powered trigger device has been developed to explosively activate suppression barriers to quench gas and coal dust explosions. The important feature of the device is a silicon solar panel, which collects 0.3 p to 1.1 D wavelength radiation from the developing explosion, and generates electrical energy to initiate a detonator, which in turn causes the rapid explosive release of an extinguishing agent into the advancing flame front. Solar panels that are rated to produce 20 w of electrical power when exposed to the sun light are producing about 200 w when exposed to full-scale dust explosion propagating in the U.S. Bureau of Mines' Lake Lynn Experimental Mine. The solar panel is electrically isolated from the detonator by a pressure sensitive switch until the arrival of the precursor pressure pulse, which always precedes a deflagration. This combination of pressure arming and flame powered photo generator prevents false barrier activation and requires no external power supply.

Jan 1, 1991

By R. L. Garrett

The quality of mineral additives used in a drilling fluid (mud) can dramatically affect the fluid's properties and the overall cost of drilling an oil or gas well. The principally wed minerals are bentonite, barite, barite/hematite blends, and hematite alone. The high specific gravity minerals, barite and hematite, are used to increase drilling fluid density. Bentonite clay is used to increase drilling fluid viscosity and gel strength and to provide a low permeability filter cake. A multimillion dollar investment in a well and the safety of the personnel on the drilling rig can depend on how effectively these mud additives perform with other constituents in the mud. This paper points out effects caused by small amounts of certain carbonate and sulfide mineral impurities in barite or hematite and how polymeric extender additives in bentonites contribute to unpredictable behavior of a mud. Effects like these are the reason oil companies using these materials sometimes set their own quality standards beyond those already specified in APZ Spec. 13A. Also discussed in this paper are the current standardization activities of API Committee 13 on these minerals.

Jan 1, 1988

By R. Candia

The use of industrial wastes, such as quarry fines of crushed stone, should represent a basic component of sustainable development indicators. Therefore, increasing investments should be foreseen in techniques of treatment and recycling of residues in mining, as well as by-product attainment that generate jobs and income. The standards of identification and discarding of industrial wastes vary significantly between countries. However, practically all nations have started becoming more restrictive regarding environmental legislation, especially concerning production, transport, treatment, recycling and final discarding of industrial wastes. Under an environmental point of view, solid wastes produced by a system (such as a quarry) can be handled in two ways: a) they can be discarded in piles or b) they can be internally or externally recycled and reused. This second practice is translated to an additional economic consequence such as an increase of income as well as a decreased environmental impact. This option is more advanced and should be included in company policy. This paper presents cases where this practice is used, i.e. diminishing the environmental liabilities through the use of the quarry fines in the manufacture of industrial devices, incorporating such wastes in the productive chain, instead of storing them in piles.

Jan 1, 2007

By L. L. Gagné

The Churchill Falls Development will eventually be the largest source of hydroelectric power in North America. Churchill Falls was discovered in 1839, but until recent years it was not practical to begin development of this site to tap the 7 million horsepower available. This $1 billion project is located in Labrador, 700 miles northeast of Montreal and 650 miles northwest of St. Johns, Nfld. The construction will divert the Churchill River 5 miles upstream from the 245 foot Churchill Falls. Rapids above and below the Falls, together with the Falls proper, give a natural head of 1,040 feet. In contrast to the basic simplicity of the surface installations, the powerhouse labyrinth is astounding in size and complexity. The largest in the world, it consists of three major chambers - the powerhouse, 972 feet long by 81 feet wide and 154 feet high; the surge chamber, 763 feet long, 40 feet to 64 feet wide and 148 feet high; and the transformer gallery, 856 feet long by 50 feet wide and 39 feet high. Other major features include eleven inclined penstocks, each 1200 feet long and 20 feet in finished diameter; eleven draft tubes averaging 37 feet in finished diameter and 162 feet long; six vertical cable shafts each an average of 865 feet in length; a series of eleven short bus tunnels linking the powerhouse and the transformer gallery; a vertical power-

Jan 1, 1997

By L. Shwydiuk, A. Chrzanowski, W. Newcomen, G. Bastin, R. Wilkins

Automated monitoring of steep embankments allows the early detection of instability and can be used to avoid or mitigate possible slope failures. A system that uses multiple and different types of sensors has been created and successfully tested at the Highland Valley Copper mine in British Columbia. The system uses robotic total stations (RTSs) as the primary measurement sensor, with surveys repeated at predefined intervals selected to optimize operational efficiency. A methodology has been developed to improve the system’s accuracy and reliability by reducing the effects of systematic errors created by atmospheric refraction and unstable instrument and reference point positions. The inclusion of GPS sensors to monitor the RTS positions creates additional operational flexibility and maintains system integrity when insufficient reference stations are available.

Jan 1, 2003

By Charles E. Melbye

INTRODUCTION In a discussion of South American exploration, it is difficult to know how much area to cover, as there has been such intense exploration for many years in all of the South American countries. Therefore, I have decided to discuss only Argentina, Bolivia and Peru in this paper, since I am most familiar with these three countries. This familiarity has been gained during my last 12 years of nearly continual exploration and mine development. Furthermore, these three countries form a contiguous block straddling the Andes Mountain chain for 2,200 miles in length N-S. Although Chile is part of this block, I excluded that country because it has had the longest recent history in South American exploration, and it is now in a mature stage where new important mines are being placed in production every year. Exploration must progress a lot for the other three countries to attain the stature of Chile. However, major exploration successes such as Yavacocha and Pieriva in Peru, Kori Khollu in Bolivia and Bajo Alumbrera, Agua Rica and Cerro Vanguardia in Argentina certainly indicates that these countries are rapidly accelerating in exploration successes and the resulting new mine developments. Also, by concentrating on three countries, I have avoided making this paper too lengthy. This paper will cover activities of both junior and senior mining companies, both of whom are making significant contributions to exploration. The junior companies often make the initial discovery, develop it further and then bring in a major company when large capital is required. Since most exploration is for gold and copper or combinations of these, most descriptions will cover these types. However, there are significant new exploration successes for zinc and for silver-lead-zinc, and they will be covered, as well. After descriptions of the various properties, there is included a discussion of the governmental policies of Argentina, Bolivia and Peru, as to how they are affecting exploration activities and budgets. Some of these problems could have a major negative affect on the future exploration plans of many companies. I have intended to cover what I think are significant exploration developments in each country, and if a company project is omitted, there was no intention to slight anyone. Since exploration results change monthly, there could be

Jan 1, 1998

The only good news in the exploration sector in 1982-a year plagued by low metal prices and weak demand-was precious metals. Gold in particular remained in the forefront, as it has for at least the past three years. The reason for this is partially due to gold's seeming resilience to conventional supply side factors-such as new production-that normally influence many other metals. Also, with projected production costs of about $6.40-$9.65/g ($200¬$300/oz), modest deposits with average grades can offer an early return on capital investment and good profit potential. Keeping escalating capital costs for new mining ventures within reason has shifted gold exploration efforts in recent years. Many mining companies are seeking relatively low grade, modest tonnage, near-surface gold mineralization. This, of course, leads to lower development costs using open-pit mining methods. Recent refinements in the carbon-in-pulp recovery process also has enhanced the economics of such deposits. Slumping economic conditions certainly played a key role in shaping exploration activity last year. Nearly every major mineral-producing state recorded exploration slowdowns. In Alaska, for example, development expenditures approached the level of exploration spending for the first time in the state's history. This not only reflects major companies' decisions to move toward production but also the economic slowdown. The worldwide recession stopped Nevada's exploration and mining boom "dead in its tracks," said John Schilling, state geologist. The year was one of layoffs and closings for the state's mines and exploration offices, he reported. Similar trends were noted in most other states, especially in the West and Southwest. In the Pacific Northwest, however, exploration appeared to continue at a relatively good pace considering the metals market. In the mining geophysical community, recent advances in telecommunications and microprocessor technology are continuing to provide a positive impact. Many geophysicists have begun using satellite digital communication links to access computer systems from remote sites where using a microcomputer would be difficult. There were also major contributions made in exploration geochemistry last year. Highlights include progress in formulating mineral deposit models, geochemical exploration in glaciated and arid environments, and publication of many informative books. The following state-by-state summary and articles on geophysics and geochemistry provides a detailed view of exploration events throughout the US in 1982.

Jan 5, 1983

By V. P. Keran, K. Leung

Two 32 foot x 14% foot, 6.4 MW autogenous mills have been installed in the Mount Isa Mines Copper Concentrator to replace the fine crushing plant, fine ore bin, rod mills and primary ball mills. This paper describes the reasons for the change, the rationale for the new circuit design and configuration, the design and scale-up processes used to size the mills, considerations for the installation of large mills inside an operating concentrator and some early operating data.

Jan 1, 1992

By F. D. Mendes, A. H. Martins

The high copper grade in the Igarapé Bahia (Brazil) gold-copper ore restricts the direct application of the classical cyanidation process. Copper oxide and sulfide minerals react with cyanides in solution, causing high leach-reagent consumption, raising processing costs and decreasing gold recovery. According to studies, a feasible solution would be to pretreat the ore to remove copper minerals prior to cyanidation. The goal of this experimental work was to study the conditions for the removal of copper from the Igarapé Bahia gold-copper ore by sulfuric acid leaching, applying a statistical approach to the experimental design. By using the Plackett Burman method, it was possible to select the variables that exhibited the largest influence on copper extraction at the sulfuric acid leaching stage. These variables were leach solution temperature, stirring speed, sulfuric acid concentration in the leach solution and ore particle size. The individual effect of these variables and their interaction influences on the experimental response were analyzed by applying the replicated full-factorial design method. Finally, the selected variables were optimized by the ascending-path statistical method, which determined the best leach experimental conditions for maximum copper extraction. The optimized leaching conditions resulted in a copper extraction of 75.5%. Keywords: Copper, Gold, Extraction, Sulfuric leaching, Optimization

Jan 1, 2003

By Biswajit Samanta, Pranjal Pathak

A multimine mineral value chain (MVC) consists of multiple mines in the upstream supplying raw materials to multiple destinations in the downstream. The short-term mine production scheduling problem of a multimine MVC aims to determine the optimal extraction sequence and destination allocation of blocks from all the mines collaboratively to meet the quality and quantity requirements of all the processing plants in each period, subject to all relevant technical and operational constraints of the mining system. It is carried out at shorter scales of days/weeks/months under the purview of long-term production scheduling. An optimal short-term production schedule for MVC involving multiple mines that share the same infrastructure (processing units, stockpiles and waste dumps) requires coordination across the network of mines. Optimizing the short-term production schedules independently at each mine fails to capture the benefit of collaboratively generating schedules for all the mines, resulting in suboptimal schedules. Additionally, in short-term production scheduling, the operations are modeled in greater detail with additional decision variables and constraints to model the more complex multimine MVC situations. This makes the large-scale instances of the problem computationally intractable for standard mixed-integer programming (MIP) solvers. This work presents a customized genetic algorithm (GA)-based heuristic approach to obtain near-optimal solutions to the industrial-scale instances of the short-term production scheduling problem of multimine MVC within a reasonable computation time.

Oct 1, 2022

By J. W. Leonard

Comments The venerable straight-line equation Y = Bx + A is again being rediscovered, but this time by economists, mining engineers and geologists. Two economists, William Sharpe and Harry Markowitz, from the University of Chicago and Stanford University, respectively, won the 1990 Noble Prize in economics by showing that the price of individual stocks can be related to the Dow Jones industrial average (DJIA) using the straight-line equation. According to Bill Chidester, Investment Analyst, Scientific Investment, Sharpe and Markowitz strongly emphasized the role of the beta (B) value while considering the alpha (A) value to be "pretty unimportant." Chidester claims that alpha is the "mystery" value that causes individual stocks to behave independently of popular stock-market indices, such as the DJIA. For many years, mining engineers and geologists have routinely called alpha the "nugget" or surprise element in geostatistical analyses in which a designated distance (x-axis) is related to the variance of the grade (y-axis). Because the influence of the independent variable (distance) over the dependent variable (grade variance) is ideal when alpha is equal to zero, any increase in alpha represents a loosening of influence or control within the relationship. This can be good news or bad news - good news if you are an economist sorting out off-trend stocks and bad news if you are a mining engineer trying to predict sulfur in a coal seam. With many mining trends, such as those involving the relationship of distance to the variance of grade, a mathematical relationship can be formed. In geostatistical analysis, the point where a mathematical trend ends is known as the sill. If the difference between the variance of grade at the sill and at alpha can be determined, then an estimate of the relative control for a given distance can be obtained by comparing the sill value to alpha. The extent to which alpha approaches the value of the sill provides an indication of independence or loss of trend. The alpha concept may find application with distance, time or fluid problems. The point of change can be either a change in trend or the trend limit. However, even without a clearly defined point of change or trend limit, increasing alpha values always infer loss of trend. Alpha analysis should be regarded as a valuable tool when sorting out many sets of mining data. The application of this user-friendly concept to reserves, material transport, fluid flow and other areas has been, and will continue to be, the basis of many important past and future developments in mining and geology.

Jan 1, 1996

By Gary Nash

While there could be as many directions on regulations as there are viewpoints surrounding the asbestos controversy, there are a few basic criteria that generally will influence government thinking, namely: - their definition of the problem to be regulated, - their interpretation of the scientific evidence available to them, and - their sensitivities to the views of, and the implications for, various interest groups in society. Clearly, different assessments of these criteria by various governments will lead to differing regulatory regimes. The consequence, of course, is a patchwork of non-conforming regulations among nations, with all that thin implies for the distortion of international trade and the unsettling of international relations. I would therefore argue that when governments are examining regulatory action, they should explicitly take into account their common interests in stable and cordial international relations, and when possible, efforts should be made to ensure that movement on regulation is at least, in principle, in accord with the general views of the international community.

Jan 1, 1984

By R. L. Ziegfeld

It has often seemed to me that people are too prone to turn to new and untried materials in an effort to solve their problems, without giving sufficient consideration to the old stand-bys, except as a last resort, It?s a little like middle-aged men who are swept off their feet by the fresh beauty of a young girl without first considering the many advantages that a more mature woman has to offer. Maybe it?s because, like the older woman, the older materials have to make a determined effort to keep themselves looking young and attractive. T at?s just about the situation with which the lead industry is laced. We have to make a determined effort to keep lead looking young and attractive to industry. However, there is one difference and it is important, Lead can not only be kept looking young, but it can, in fact, actually be kept young, This results from two things. First, industry and technology are constantly changing. For example, we have known for years that the density of lead makes it ideal to stop gamma rays, but it is only recently that atomic fission as a source of gamma radiation has become an important tool of industry, That makes old knowledge about lead useful in developing a new market for it.

Jan 1, 1958

By Steve Rogers

Nautilus Minerals was listed on the Toronto Stock Exchange in May 2006. The company now has major mining companies Anglo America (5.7%), Teck Cominco (7.2%) and Epion Holdings (22.4%) as significant shareholders, and has raised approximately $US346 million dollars to develop the world's first deep-water mine. The company is currently targeting high-grade copper and gold in seafloor massive sulphide mineralization, located near plate boundaries in back-arch basins of the Western Pacific. The first mine scheduled to be developed by the company is located in 1,600 meters of water at Solwara 1, in the relatively quite waters of the Bismarck Sea approximately 50 km from the port of Rabaul, within the Territorial Waters of Papua New Guinea. During 2006 and 2007 the company completed detailed environmental and geological studies, culminating in a number of world firsts, including the world?s first NI 43-101 compliant resource statement and environmental impact study for a seafloor massive sulphide system. Permitting is well advanced for the project, with initial production scheduled for late 2010, subject to timely grant of the permits. Extensive government and stakeholder liaison and engagement has been undertaken throughout the projects life, and is a core feature of Nautilus' desire to "do it right" in all aspects of this new industry.

Jan 1, 2008

By BEN WANG, HAORAN LI, YALI FENG, JINRONG JU

Acidic wastewater is at present directly neutralized with lime or limestone, which wastes resources such as titanium, scandium and iron and generates a great deal of solid waste. This study proposes a novel approach for the separation and recovery of titanium, scandium and iron from acidic wastewater, and utilization of red gypsum. The proposed process not only recovers valuable metals from acidic wastewater but also treats the red gypsum that has previously been dumped.

Aug 1, 2022

By William T. Griswold

Few metals or industrial minerals can boast a better growth record over the past fifteen years than the borates. This period of growth occurred before the influence of any large-scale use in plastics or high-energy fuels. These new developments not only provide expanding markets, but the programs related to their development are generating research information that will lead to many other new uses. The most dynamic growth areas for refined products of boron or borates are in the acid, the oxide and the reduced forms, such as the metal and the hydrides. Expanding requirements for these products will modify the emphasis on the use of naturally occurring sodium borates. Any borate from which boron can be economically extracted will become a potentially important ore. This is particularly true of the calcium borate, colemanite. Only one large deposit in the Western World has ever been developed where the principal economic minerals are sodium borates, This factor alone would discourage any exploration program directed solely toward the discovery of these ores; on the other hand, ample exploration opportunities for calcium borates exist in the desert regions of California and Nevada. It is therefore reasonable to restrict a program to this region, in spite of geologically favorable areas in foreign countries such as Turkey, Argentina and Chile.

Jan 1, 1959