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Development of process control in the metallurgical industry over the past ten years has been highly influenced by technical advances centered on use of computers as well as on measurement and associated equipment. The discussion in this section reviews advances in computer technology, measurement devices, data input-output techniques, and their use in mineral processing for the objective of guiding application of process control principles. Advances in the next ten-year period through the 1980's can be foreseen in the cost and application of data handling facilities in the coincident fields of data processing equipment, interface and control devices, and computer programming systems. These will lead to greater acceptance in a widely expanding range of mineral processing fields. It can be predicted that process control methods now known to be effective will become more re- fined. Costs of on-stream analyzers for assays and particle data will be reduced. Continued innovation can be anticipated in measurement devices required for effecting control. Control techniques developed over the last decade in key process operations such as crushing, grinding, flotation, smelting, and hydrometallurgical processes are described in the following chapters. The general forms taken by computer process control are first outlined briefly.

Jan 1, 1979

By Robert L. Bates

An industrial mineral, says the Glossary of Geology, is "any rock, mineral, or other naturally occurring substance of economic value, exclusive of metallic ores, mineral fuels, and gemstones; one of the nonmetallics." Probably most geologists and engineers would accept this simple and straightforward definition, at least as a general statement. On analysis, however, certain anomalies crop up. For example, what is metallic and what is nonmetallic? Bauxite and ilmenite certainly qualify as metallic ores, but both are also raw materials of important nonmetallic substances; hence they are included in this book. Another anomaly is that, by common consent, the term industrial minerals may include not only rocks and minerals but also certain manufactured products, such as cement and lime, and even mixed groups of natural and artificial products, such as abrasives and refractories. Thus the central realm of the industrial minerals is clear enough, but its boundaries tend to be indefinable. Since a definition that allowed for every irregularity in the outer fringes would be excessively unwieldy, the one quoted above may be considered satisfactory. The expression industrial minerals is commonly equated with nonmetallics, and with the somewhat more precise phrase industrial minerals and rocks as in the title of this book.

Jan 1, 1994

By James R. Boulton

Fire detection using Carbon Monoxide sensors is based on the assumption that a rise in the level of Carbon Monoxide in the atmosphere over a fixed, predetermined ambient level is indicative of a fire. The method is simple, reliable, and effective in those mines where the only source of CO is from undesired combustion. Ambience for this purpose is defined as that level of the gas that is present on a day to day basis whose source is not a fire. In a diesel powered mine the level of CO can and does vary so widely from hour to hour and minute to minute that the selection of a predetermined, fixed level represents a compromise between sensitivity and reliability. The compromise is a best of both and worst of both situations and the computer system often resembles the little boy who cried wolf instead of a state of the art early fire monitoring and detection system. Cyprus Coal personnel have developed method of determining the ambient level of CO in the atmosphere on a real time basis and using that dynamic ambient level to determine whether or not a fire exists in the mine. The method has been given the name of Wave Trend Crossing.

Jan 1, 1991

By Robert Snow, Yingxue Yu, Howard Hanson, Patrick Zhang

One of the major current efforts by the Florida phosphate industry to reduce deep aquifer water consumption is to use 100% recycle water for flotation. This measure alone could save billions of gallons of deep well water annually. However, this also results in higher suspended solids (slimes) in flotation water, causing poor process performance particularly for amine flotation. Polymers could play a major role in allowing the industry to use high-turbidity recycle water for amine flotation without compromising its impact on the Florida economy. The enhancement of rougher flotation by polymers may also have potential. Most importantly, dramatic efficiency improvement may be realized by floating silica first. Adding polymer to flotation feed and/or water is perhaps the most economically viable way of reversing the Crago "double float" process, in order to reduce operating costs and increase phosphate recovery. This paper presents both laboratory and pilot flotation data showing the effect of different polymers on collector dosage and flotation recovery. There appeared to be an optimal range of polymer concentration beyond which the benefits do not offset the drop in phosphate recovery. The effect of poly mer is slime-level dependent. Pilot testing data show that the "Reverse Crago" process (floating silica first followed by phosphate flotation) can outperform the Crago process.

Jan 1, 1999

By H. Polat, B. Mohal, S. Chander

Several nonionic surfactants and one anionic surfactant were tested to enhance the flotation response of a low-rank coal. The nonionic surfactants included an ethoxylated octylphenol and several polypropylene-polyethylene block copolymers, and the anionic surfactant was a dioctyl sulfosuccinate. All of the surfactants improved the yield significantly, but the influence on grade was complex. To elucidate the mechanisms involved, separate studies were conducted to determine the emulsification behavior of the surfactants. For the nonionic water soluble reagents, a correlation between the emulsifying power of the surfactant and the flotation response was observed. An increase in the number of droplets produced was considered to he the main reason for increases in the yield. However, a small amount of surfactant adsorption on coal is essential to promote adhesion of oil droplets. When the surfactant was introduced into the flotation pulp prior to addition of dodecane, the benefits of the surfactant decreased significantly. The decrease was attributed to both a decrease in hydrophobicity of coal through increased surfactant adsorption and a decrease in the surfactant available for emulsification. When a surfactant dispersed in oil was used, the transfer of surfactant to the aqueous phase was minimal, and a considerable increase in yield was observed.

Jan 1, 1995

By Alfredo Menendez, Alberto Sarmentero

A B S T R A C T The Los Pijiguaos bauxite is one of the largest accumulations of trihydrate alumina ore recently discovered; it is a plateau type, with no overburden, relatively soft tertiary quartz-bearing bauxite developed on a pre-Cambrian Rapakivi Granite batholith. The deposits are found in the northwestern rim of the Guiana Shield, State of Bolivar, Venezuela, and were discovered in 1976 after a grass-roots exploration campaign. Target areas were mainly selected on the basis of geological and geo¬morpholigcal criteria, guided by correlation with known deposits elsewhere in the Guiana Shield. The vertical. lateritic profile consists of an upper concretionary zone, followed by a mottled zone, a palid zone and finally the weathered rock merging into fresh granite. The upper concretionary zone displays a cellular, pisolitic or spongy texture and contains the following minerals: gibbsite (60-90%),quartz (5-10%), hematite (5-10%), goethite (under 5%), boehmite (traces), kaolinite (traces). The gibbsite content decreases sharply downward from the lower limit of the concretionary zone and the kaolinite and quartz content increases in the underlying mottled zone. The mottled and palid zones display a pseudo rapakivi texture and quartz, kaolinite and mica are the. essential minerals.

Jan 1, 1984

By J. A. Organiscak

Data on dust-control practices, mining conditions and occupational exposures were gathered for approximately 80 underground continuous mining units. Despite silica contents on dust samples in excess of 5%, nearly forty units successfully maintained silica concentrations at or below 100 µg/m3 on a majority of occupational dust samples, while the remainder had difficulty maintaining this level. These two sample sets were termed Group A operations and Group B operations, respectively. This data was compared to identify causes of high occupational silica dust exposures. Analyses of dust-control parameters and geologies revealed only minor differences between these two groups. However, subsequent comparisons of face ventilation design showed considerable differences in silica exposure and silica content between Group A and Group B at the continuous mining machine and roof bolter operator occupations. These differences were minimal when using exhaust curtain ventilation with a dust scrubber. This face ventilation system can benefit operations having difficulty controlling silica dust exposure and silica dust content. The collected data also showed that occupational samples from Group B operations possessed generally higher silica exposures and silica content than similar samples from Group A. The single head roof bolter (helper) possessed among the highest silica exposures and silica contents in both groups.

Jan 1, 2002

Ever since A Decade of Digital Computing in the Minerals Industry was published in 1969, mining men have expressed the need for an additional reference on computer methods. It was felt such a volume should spell out the "how to" of computer applications in the solution of their problems. Computers in the minerals industry will be 20 years old when the 1979 SME Fall Meeting and the 16th International Symposium on the Application of Computers and Operations Research in the Mineral Industry (APCOM) take place jointly in Tucson, AZ. On such an occasion it was thought appropriate to publish an anniversary volume which reviewed current practices and projected what might prevail as computer methods for the future. Thus was born the idea to publish Computer Methods for the 80's. The first planning meeting for this volume took place in Las Vegas, NV, during the 1976 annual meeting of the American Institute of Mining, Metallurgical, and Petroleum Engineers. It quickly became evident that no single computer method existed to solve most mining problems; rather, mining computer methods are generally tailored to fit unique geologic, mining, and organizational conditions. Hence a format which included both the theory and practice for each of the computer applications was adopted for this volume.

Jan 1, 1979

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 W. F. Kane

Underground geologic mapping is an extremely important aspect of any on- going ground control plan. However, the actual use of data derived from such a program is difficult and often leads to subjective analysis. In this regard, computer software has been developed that utilizes a statistical determination of unstable ground conditions based on geomechanical and operational data and collected by mine personnel on a mine-wide, or regional basis. Categorical variables, such as faulting or joint frequency, are selected from local experience to form the framework of a representative data base. Statistical comparisons between the selected variables and a particular ground control problem are conducted and correlations subsequently made. The probability of encountering unstable conditions in virgin areas is assessed as information from these regions is gathered. This data can be derived from surface mapping, cores, and/or geophysical logs. As mining progresses, new data is merged with the existing data base to form a more comprehensive and extensive unit. The advantages of this approach and the acquisition and maintainence of a large data base include the more accurate representation of existing mining conditions, increased confidence in analyzing future problem areas, and elimination of the difficulties which arise when using ground control theories derived for other, often very different, locales.

Jan 1, 1986

By Bela Koman

Abstract - A shiploading terminal near Punta Arenas, the southernmost city of the world (lat. 53°-10'S, long. 70°-54' W) is described. Strong winds, choppy seas, frequent gales, rain, and snow make it difficult to load ships at an offshore berth in this area. Detailed site investigations, including a wind-recording program, supplied sufficient information for the analysis of operating conditions. The weather pattern of the entire region, including the predictability of gales, was utilized in the analysis. The results showed that a bulk loading terminal at this location is feasible, provided that the design takes into consideration the specific problems of the site. The final layout shows a terminal that can be approached from several different directions, depending on the direction of the wind. The mooring system is arranged to allow alter- native ways of attaching and casting off mooring lines and executing docking and departing maneuvers. The berth is supported on piles and contains the minimum of structures, relying on a slewing shiploader to reach the ship in any position, with only limited fore and aft shifting of the vessel for loading the extreme hatches. Results of wind recording, statistical analysis of wind and wave data, operating criteria, and the results of berth availability analysis are included in the paper.

Jan 1, 1987

By P. N. Thompson

The past few years have seen the introduction of mini-computers on an increasing scale at collieries in the British coal industry. These are being used for controlling underground transport systems, coal preparation plants and fixed plant (pumps etc.); and for monitoring the mine environment and face operations.. A separate mini-computer (termed a primary computer) is dedicated to each of these functions. The overall system under which these computers operate is a common one which is applicable at all collieries. The information collected by the primary computers, other than that required for immediate control, will be fed to a secondary computer for analysis and processing. This overall concept, called MINOS. (MINe Operating System) is being developed by the National Coal Board's Mining Research and Development Establishment (M.R.D.E.). Eventually most of the data required by the system will be captured automatically. For example, the fact that a delay has occurred on a face, together with the duration of that delay, will be detected automatically via transducers link linked to a primary computer. However, the reason for that delay will, in all likelihood, have to be recorded manually. Such a system is currently under development with the first trial installations now being made.

Jan 1, 1979

By Tom Skodack

Mine and tunnel contractors face a complex environment-one in which economic risks are high, operating costs grow ever higher, ore grades are lower or recovery more difficult, and civil construction projects are intensely competitive on a world-wide scale. Within the context of this environment, the risks and rewards of proper machine selection for rock excavation have become proportionately large. Speed, depth and scope of analysis, and extensive supporting information are indispensable in the selection process. Equipment designs and their applications are also myriad and diverse. Several equipment alternatives and excavation techniques may have to be evaluated at once to choose the most cost-efficient approach. The following examples are typical of the current demand for more detailed equipment analysis: • An aggregate supplier starts a new quarry. He knows his targeted tonnage, blasting restrictions, and previous operating costs from other quarries. But he must improve on his old costs. What drill pattern, hole size, and bench height will give lowest cost per ton? How many crawler drills and what type will produce this tonnage most efficiently? • A mine is using a fleet of twin pneumatic ring drills for long hole drilling to initiate their cave. The mine is facing both air shortages and increasing operating costs with decreased efficiency in the ring drill fleet. If they invest in new hydraulic long hole drills, what impact will each drill unit have on production? Each twin drill unit? What configuration gives best operator efficiency and subsequent reduction in manpower? Which configuration gives the best return on investment? • A tunnel contractor is bidding a long straight water tunnel by conventional drill and blast methods. What is the optimum number of drill booms for the tunnel cross section and excavation schedule? How many rounds per day can he achieve? What are his total project drill, blast, and muck costs? In the past, such questions could be answered, but only approximately at best. One good prediction could involve many hours of laborious calculations that had to be repeated each time a new parameter was introduced or an existing parameter changed. In 1980, increasingly complex analysis, coupled with increasing need and quick response times demanded by industry, led Atlas Copco's project department to turn to the computer. New computer programs based on theoretical considerations and three decades of worksite performance data were developed for evaluating mine and tunnel contractors' equipment needs, productivity, and partial or total operating cost calculations for most conventional drill and blast excavation techniques-including shot rock loading and transportation. This Computerized Analysis of Rock Excavation-or CARE-program has since been available to the mining and construction industry. From each program specific results can be pre- dicted, including: • Productivity Calculations-Rock drill penetration rate for a given drill, hole size, and rock type, optimized for the best drill steel life; net machine productivity (drill-out time or drill meters-footage-per shift); total drill round time, including charging, blasting, loading, and haulage; suggested drill pattern, computer printed, including hole size for a given rock drill, rock type, and associated blasting restrictions for either drift rounds or benching applications; long-hole drill meters (ft) per drill shift; breasting down (upper drilling) drill meters (ft) per drill shift; and comparison between continuous loading machine capacity and LHD capacity. • Operating Cost Calculations-Operating costs expressed as cost per drill meter (ft), cost per cubic meter (cubic yard) of excavated rock, and cost per meter (ft) of tunnel advance. These costs may be calculated using as many cost centers as the mine, quarry, or tunneling contractor wishes. Specific operating costs may cover drill rig operating costs only, less capitalization; drill rig operating costs, including amortized equipment investment; drilling and blasting costs; drill, blast, load, and haulage operating costs; long-hole drilling operating costs per drill meter (ft) or per blasted cubic meter (cubic yard) of rock; and loading and transport operating costs. In all the above cases, any number of cost and capacity calculations may be run by simply changing important cost center variables to judge their net effect. Accuracy as a Function of Input Data and the Statistical Data Base Accuracy of a projection clearly depends heavily on the data base from which the projection is drawn.

Jan 11, 1982

By Terry Mattioli, Buck Bradshaw, Terry Fagg, Larry G. Nisle

Deposition of calcium carbonate scale on activated carbon in the Pinson Mining mill carbon column circuit was causing erratic gold recovery rate, long acid wash time, high carbon attrition and long strip times. Continuous addition of a blended antiscalant into the mill thickener overflow at 8 ppm reduced the average carbon acid wash weight loss from approximately 10% to < 2%. Cleaner carbon improved the gold loading rate in the mill column. The loading on Column I was increased to 175-225 oz/ton carbon from 125-150 oz/ton for a two-day carbon advance cycle. The higher loading capability has given Pinson more flexibility and better control of gold flow through their carbon adsorption, stripping and electrowin­ning processes. Preventing calcium carbonate build-up on activated carbon with this antiscalant reduced acid wash batch time. This enabled Pinson to acid wash and regenerate every batch of stripped carbon for all the adsorption circuits. Shorter strip times have also resulted from the lowering of the calcium carbonate scale level in the loaded carbon. Carbon consumption has been reduced and is now averaging 0.046 lb/ton ore for the first six months of 1990 compared to 0.072 and 0.083 lb/ton respectively in 1989 and 1988.

Jan 1, 1990

By Gary D. Babbitt

Facing an orchestrated assault from the anti-mining lobby and its congressional allies, the Mining Law of 1872 may soon be either dramatically changed or even repealed. In 1989, Sen. Dale Bumpers (D-AK) introduced Senate Bill 1126 entitled the "Mining Law of 1989." It has been through several hearings and is still in the Senate Committee on Energy and Natural Resources, where Sen. Bumpers is the number two ranking Democrat. In the House, Rep. Nick J. Rahall (D-WV) introduced the "Mineral Development and Exploration Act of 1990," HR 3866. This bill is in the House Committee on Interior and Insu¬lar Affairs. (The numbers on these bills, and perhaps some of their language, will be changed when they are reintroduced in early 1991. However, their substance is expected to remain substantially unchanged. Bill numbers here refer to legislation as it was numbered in the 1990 Congress.) In the eyes of its supporters, Bumpers&apos; S 1126 appears to be more complete and has the inside track over the Rahall bill. Bumpers&apos; bill includes provisions for royalties, bonding and reclamation. The Rahall bill is criticized by opponents of the Mining Law for its failure to include a royalty provision and for not having specific bonding and reclamation provisions.

Jan 1, 1991

By J. A. Eisele, G. E. McClelland, M. D. Wroblewski

The Bureau of Mines is conducting research at its Reno Research Center to develop a staged agglomeration-heap leaching system and to electrowin the dissolved precious metals from the pregnant leaching solution. For direct electro- winning to be successful, the pregnant solutions generated during the Initial stages of leaching must be higher grade than obtained by conventional heap leaching. The precious metal concentration of the pregnant solution can be Increased by agglomeration pretreatment with cyanide solution which starts the leaching process during the curing period, by leaching with small volumes of solution and by cycling the leaching solution through more than one heap in a staged manner. The resulting pregnant solution is passed directly through an electrowinning circuit. The barren solution from electrowinning is recycled to the leaching circuit. Bench-scale research on the development of the staged leaching system and on the development of an efficient electrowinning cell are described. The Bureau of Mines developed agglomeration- heap leaching technology. This technology was readily adopted by the mining Industry for heap leaching crushed ores and mine wastes. Current research involves the application of this technology to finely ground feed materials such as precious metal-bearing milled tailings. Tailings agglomeration-heap leaching has also been used commercially.

Jan 1, 1984

By John M. Karpinski

A method and equipment have been developed Tor measuring the impact strength of grains of brittle materials. It is shown that brittle materials develop a characteristic particle size distribution when fractured by impact. A simple mathematical model has been found to describe this distribution, and one of the parameters of the model has been designated the r value. The r value is directly proportional .to impact energy and, for fixed impact energy, it becomes a useful criterion of grain strength. Data are presented on the variation of the r value as a function of sample history, initial size, energy input and number of impacts, The results are interpreted in terms of the flaw theory of brittle fracture.

Jan 1, 1964

By John E. Edkins

Metal sulfides, chiefly pyrite and mFnor sphalerlte zssociated with che Herrin (No. 6) coal member of the Pennsylvania Carbondale Formation, have been concentrated in a coal refuse deposit in southern Illinois. Oxidation of pyrite has produced highly acid waters with high concentrations of iron, zinc (up to 200 parts per million) and toxic trace elements that have leached downward to a water system perched on glacial drift. Chemical, petrographic, low-temperature ashing and x-ray diffraction were performed on cores. The data show that economic recovery of zinc and other trace metals is unlikely at this site. Energy (coal) recovery at the Superior Washer site is possible if resultant environmental problems are considered in the planning.

Jan 1, 1981

By Tadashi Nishida

Subsidence due to mining caused various kinds of damage to the surface structures, and actually great deal of mining damage becomes the severe social problem at some time in many coal fields, but the most of mining damage was restored at present. Recently, the effect of old coal working on the deformation of newly constructed structures has become into question, because it was obliged to plan many engineering structures in old mining areas for the shortage of adequate construction sites and the difficulty of getting location. That is, building, dams, bridges for railroads and highway, power plants, tunnels, storage tanks and so, have to be built on the ground which has old coal working.

Jan 1, 1982

By Charles M. Brinckerhoff

Everyone -- especially the engineer -- is aware of the great technological and social changes taking place in our world today, We realize that changes have been taking place since man&apos;s beginnings on earth, but the element we now face is the speed of change, rather than change itself. Developments in medicine, in transportation, in space exploration, in global communications, and in many other fields, are constantly being made known. These developments are affecting the lives of each of us, although some may appear remote and unrelated to us as individuals. New developments, almost on a daily basis, affect our work as well as our social, religious and educational lives. The effects are immediate and permanent.

Jan 1, 1967