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By L. A. Puchkov

Problems of how to use artificial intelligence (AI) methods and expert systems (ES) to control complex industrial projects have lately become significant in practical terms. Mining ventilation systems undoubtedly belong to complex multi dimensional objects of control with stochastic nonstationary and nonlinear processes. Formal models based on automated ventilation control, do require awkward algorithmic solutions, moreover, a number of tasks become the operator's headache, and the quality of their solution depends on his experience and intuition. These tasks include: - identifying pre-accidental situations and determining their causes; - making well-grounded decisions with regard to changing ventilation regimes, forecast of mining operations taken account of; - controlling ventilation systems in emergency situations, e.g. when in accident, etc. It is in this context that we have for a number of years been investigating how to practically use AI methods for operative control in dynamic aero-and-gas mining processes, one of our research directions being devoted to working out a consulting programme for the ventilation system operator. Our researching and modeling problem was identification of aero-and-gas situation in different parts of ventilation network and its interpretation in order to determine possible causes for gas regime changing and unexpected consequences. We would single out the following stages in this task: I. Operative information procession coming to the data base from the sensors and analysis of hypothetical versions (using the associative rules base) with regard to factors which have caused significant parameter fluctuations (e.g. C%(t), H(t), Q(t) etc.)., 2. Selection of hypotheses in the knowledge base and forming conclusions in accordance with reliability scale. 3. Clarifying the obtained conclusions in dialogue with the operator. 4. Correcting the associative rules base.

Jan 1, 1992

By Olav Moklebust

The R-N Process is an outgrowth of the development by the National Lead Company's Norwegian subsidiary Titania A/S, of a process for producing metallic iron and a high titanium content co-product from ilmenite. Development of the process for the treatment of iron ores was continued as a joint project of the Republic Steel Corporation and the National Lead Company in 1953. More recently in July, 1957, the R-N Corporation was created by these two companies to undertake the commercial promotion of the results of this joint project. This paper has been prepared with the permission and encouragement of these three companies. The R-N process has as its objective the making of metallic iron from iron ores or iron ore concentrates. The general principles of the process have already been disclosed in technical papers and patents. In general the process comprises the following steps: 1. Iron oxide in crushed natural iron ores or iron ore concentrates is reduced to about 95% metallic iron, without fusion in a rotary kiln in the presence of solid carbonaceous fuel,*such as, coke or char, limestone and combustible gases. 2. The kiln discharge, consisting of metallized ore, coke, lime and coke ashes, is cooled. The excess coke is regenerated and recycled to the kiln feed.

Jan 1, 1959

By H. K. Pelzer

Belt conveyor systems for long-distance haulage are nowadays in a competitive position with conventional methods of transportation such as railways, truck haulage, and also pipelines for solid materials. In a number of cases, the economical use of conveyors is obvious. This is in all those cases where typical features of a conveyor system are showing the outstanding economical position in the very first approach for a certain project. Regarding downhill conveyors, with today's level of belt conveyor techniques nobody would reasonably doubt the justified application of a conveyor system, - as for instance at the Marcona Mining Installation, or at the iron ore mine of Lamco in Liberia.

Jan 1, 1968

By Martin P. Corriveau

It is not news to anyone in the mining industry that federal action in the prevention and abatement of air pollution has seriously affected the industry both directly and indirectly. It is the purpose of this paper to review how the development of federal action is directly affecting the coal mining industry's number one customer, the fossil-fuel-fired steam generating power plants and, consequently, the industry itself indirectly. In essence, Public Law 84-159 of 1955 as amended by the Clean Air Act of 1963 and its revisions in 1967 and 1970 progressively tightened federal coordination and management of air pollution control programs throughout these United States. The Environ- mental Protection Agency (E.P.A.) set up to direct the programs was charged to establish National Air Quality Standards, Standards of Performance for New Stationary Sources, and National Emission Standards for Hazardous Air Pollutants.

Jan 1, 1973

By Graham J. Morgan

The following material is excerpted from a presentation Mr. Morgan gave recently to representatives of the financial community. Introduction 1982 was a period of challenge for United States Gypsum Company because of reduced market opportunity. Housing starts for the first 10 months averaged a seasonally adjusted annual rate of 1 million units, 9% below the comparable 1981 period when housing starts were the lowest in 35 years. Industry gypsum board shipments declined 9% from the already low levels of the same period in 1981. US Gypsum met the challenge with stringent cost reduction programs and aggressive action in the marketplace. In late 1981, anticipating market deterioration, the company's management adopted strategies to focus on two shortterm objectives: • Adjust operations to perform profitably in view of limited opportunities through more efficient operations and asset management. • Continue to strengthen U.S.G.'s resources and ability to take advantage of important market opportunities as the economy improves through selective expansion of production capacity in key growth markets. Concentration on these two objectives resulted in a nine month performance in 1982 that, while certainly not satisfactory by company standards, compared very favorably with that of principal competitors in terms of net earnings, margin on sales, and return on average stockholders' equity. To counteract limited market opportunities, U.S.G. focused on productivity improvement, cost reduction, expense control, and maximization of market penetration. Energy Use Improving performance encompassed all segments of operations. For example, efficient use of energy was a significant factor despite lower operating rates at most plants. Overall, in the third quarter of 1982 versus 1972, the company used 27% less energy per unit of production, a savings of $15 million in that quarter alone. These continuing improvements helped to partially offset constantly rising energy costs. A number of operations achieved superior results in the first nine months of the year compared with the same period in 1981. For example, gypsum board plants in Jacksonville, FL, and Sweetwater, TX, recorded 8% and 7% reductions, respectively, in energy use per unit of production. Paper mills in Oakfield, NY, Galena Park, TX, and Kansas City, MO, each reduced energy use more than 12%, while the Greenville, MS, ceiling products facility achieved a 16%o reduction. Safety Safety is another important element that received increased attention. U.S.G.'s safety performance over the past five years has consistently improved. In 1981 it was five times better than that of the gypsum industry; nearly 10 times better than all industry as measured by the National Safety Council; and almost 20 times better than all US manufacturing as recorded by the Bureau of Labor Statistics. In addition to human concerns, this excellent record results in significant dollar savings that directly affect company results. In 1981, U.S.G.'s pre-tax savings in claims, premiums, and related expenses were about $20 million compared to the industries in which it competes. For the first half of 1982 performance improved further, with a cumulative lost workday incidence rate per 200,000 man-hours worked of only 0.27, an all-time record. Expense Control Careful control of inventories and receivables also received special attention. As of Sept. 30, 1982, inventories were 29%, or $44 million, below the level of Sept. 30,

Jan 2, 1983

By M. F. Corcoran

Rapid advances have been made in the past few years in the application of automatic controls and instrumentation to iron ore pelletizing plants. Present practice in applying instrumentation and control to the Grate-Kiln system of iron ore pelletizing is described. Major control points and loops are tabulated. Future trends in the application of digital control including computer data logging systems are described.

Jan 1, 1965

By Harry H. Posey, John Woodling, Miriam L. Renkin

Natural acid drainage is generated from pyritic rock underlying 17 percent of the upper Alamosa River basin. About one-third of these acid producing rocks have nil carbonate buffering capacity; there the streams carry significant acid plus dissolved Al, Cu, Fe, and Zn. In part of the basin, aquatic life is limited by the natural acid drainage. In the four miles where the Alamosa flows through pyritic rock the river grows toxic to trout. Inhospitable conditions continue downstream for at least another four miles. The waters become refreshed, naturally, through metal dilution, metal oxide and hydroxide precipitation, and acid neutralization. Water quality fluctuates in seasonal cycles. Dissolved metals and acid, which are generated year-round by weathering, are stored over winter in the unsaturated zone in the retained water and in soluble metal- sulfate minerals that form by evaporation of acid-metal waters. Seasonal discharge variations cause metal concentrations and pH to shift in the trunk stream; the acid drainage source streams, however, shift only slightly by season. In early spring, metal concentrations and metal loads increase as metals and acid are flushed from the unsaturated zones by melting snow. Peak metal loads occur at this time, and precede peak flow by up to two months. Other metal load peaks occur during peak flow and monsoon flow, even though metal concentrations are diluted at that time by precipitation. In late spring and thereafter, discharge of neutral pH water wanes, so trunk stream pH falls and metal concentrations return to previous high levels. Metal concentrations appear to be low from November through January when dilution from precipitation is lowest, but rise in February to near peak yearly concentrations. In years with high monsoonal flows, metal-laden waters apparently flush from the unsaturated zone and metal concentrations remain low from about October through January. In years with low monsoonal flows, however, metal concentrations in October and November at least are higher.

Jan 1, 2000

Sphalerite is commonly floated in an alkaline environment and under such conditions the overall activation mechanism is obscured by the hydrolysis of Cu2+ and precipitation of Cu(OH)2. Electrokinetic and kinetic flotation tests show that the activation of sphalerite is a two-stage process; the activation products formed on the surface of sphalerite in near neutral and in alkaline solutions in the first rapid activation stage are "flotation-inactive". These layers, when formed in an alkaline solution, are unstable and are transformed into the "flotation-active" form in the second stage. However, the surface layers formed during activation in alkaline environment by copper in the presence of lead ions are very stable and even after a long conditioning time the flotation rate is not improved. Consequently, while both Cu2+ and Pb2+ activate sphalerite flotation, quite unpredictable effects may result when both are present in the solution.

Jan 1, 1997

By D. E. Ranta, M. G. Schulz

Mining of Molybdenum at Questa, New Mexico has been accomplished by block cave methods since August, 1983. As caving progresses, a periodic geologic evaluation is made of the rock types present in finger raises on the Grizzly Level of the mine. The production maturity of the cave can be monitored by relating this data to geologic cross-sections through the orebody. The draw point mapping program is a simple and effective tool that is used in making draw control decisions at Questa.

Jan 1, 1992

By S. B. Patton

To fully utilize a ventilation simulator as a planning and production tool, the network database must keep pace with mining progress. By using AutoCAD's attribute-definition function, the branch data and node coordinates can be stored as part of the branch-diagram file, and updated with the drawing. Attributes are drawing entities that contain text which can be extracted in a standard spreadsheet format or as an ASCII text file. The data can be subsequently loaded into a ventilation simulator with plotting capabilities, such as VNETPC. This paper presents the methodology for using AutoCAD's attribute feature in a ventilation simulation.

Jan 1, 1994

By Alvaro Souviron, W. W. Atkinson

The porphyry copper deposit at Los Pelambres is a resource exceeding 2 Gt (2.2 billion st) of 0.7% copper and 0.02% molybdenum. It includes a high-grade zone of +1% copper that is amenable to open-pit mining with a low stripping ratio. Metallurgical testing has indicated that the ore has exceptional characteristics, and that recoveries of 96% for copper and 93% for molybdenum can be obtained by conventional flotation methods. This paper summarizes the history of the prospect, the geology of the ore body and the surrounding area, and the procedures and results of exploration.

Jan 1, 1987

By K. Biswas

In general, it cannot be assumed that the strength of coal pillars remains constant over long time periods. Field observations indicate that a coal seam, especially when it contains a parting layer, deteriorates over time, reducing load-bearing capacity of the pillars. This paper discusses a unique approach to determine the time dependent strength of coal pillars in the field. Three coal pillars that were developed 5, 15 and 50 years ago were chosen for the study. Holes were drilled in coal and parting layers in each pillar and the strength profiles were determined for each hole using the Borehole Penetrometer. The strength data were treated statistically to establish time dependent strength equations for different layers. The results can be used to help estimate the loss of pillar capacity over time.

Jan 1, 1999

By T. J. DeMull

AMAX's Sleeper Mine uses conventional cyanidation milling and heap leaching techniques to produce gold. Since milling operations commenced in March 1986, average ore processing rates have improved from the design rate of 455 tonnes per day to more than 720 tonnes per day. Heap leaching was added to the process facilities in September 1986 at a design rate of 1,500 tonnes per day, and current heap leaching rates exceed 2,680 tonnes per day. Presented are descriptions of the Sleeper processing facilities with emphasis on the crushing and grinding circuits, a review of the selection of crushing and grinding equipment, and a summary of operating performance during the first 16 months of operations.

Jan 1, 1988

By D. W. Scott

Ontario has a diverse industrial mineral resource base including abundant resources of structural industrial minerals such as sand and gravel, crushed stone, building stone, clay, shale, limestone and dolostone. These resources are used in the production of aggregates, brick, metallurgical stone, fillers, lime, cement and other construction materials. The majority of the operations are in deposits of Paleozoic and Quaternary age in southern Ontario, close to the major markets. Province-wide, there were over 140 million metric tonnes of aggregates produced in 1985, approximately 115 million tonnes of which was produced in southern Ontario with the remainder being largely from Crown land in northern Ontario. The structural industrial minerals account for over 80% of the value of total industrial mineral production, with the remaining 20% of the value king accounted for by the non-structural minerals being led by salt which is produced in southwestern Ontario. A host of other non-structural industrial minerals are known but production is currently restricted to calcite, gypsum, quartz, talc, nepheline syenite and by-product metallurgical sulphur products (Fig. 1). Location and Market Area Major production is in the area closest to the large markets of urbanized southern Ontario and the northeastern and north-central United States. In general, with the abundant variety and widespread resources of industrial minerals and the large population within 400 miles of most deposits, the market offers great potential. Ontario's 9 million population accounts for about 35% of the entire gross domestic product of Canada of $476.361 billion dollars in 1985. This equates to about 113 of the nation's buying power being within a 200 km (125 miles) radius of Toronto. This major concentration of industrial and economic activity has resulted in a well developed industrial minerals industry fulfilling most of the structural industrial minerals demand in Ontario, as well as a subsidiary demand in neighbouring provinces and states.

Jan 1, 1987

By J. J. Kollé

A compressed-water hydraulic pulse generator (HPG) for nonexplosive blasting of rock and concrete is described. Energy is stored in the HPG by compressing water to ultrahigh pressure. A large, fast-opening valve discharges the compressed water, resulting in a high-energy impulse. The HPG can be used for small-scale bench blasting by discharging the water through a nozzle that is closely fitted into a borehole. A bench blasting system requires an HPG, a drill and an indexing mechanism to allow insertion of the HPG nozzle into a drilled borehole. Systems with discharge energies ranging from 40 to 250 kJ have been used to excavate hard rock, including andesite, granite and quartzite. The largest system can excavate 15 t/h (16.5 stph) of massive quartzite based on a 2-min cycle time for hole drilling. Blasting with an ultrahigh -pressure hydraulic pulse generator was demonstrated as an effective means of excavating hard, massive rock under the confined conditions of a tunnel opening or underground sloping panel. Hydraulic blasting provides a continuous mechanized mining capability that is well suited for deep-level mining and urban excavation sites where explosives are prohibited.

Jan 1, 1998

By A. S. Malicsi, Vathsala Rajagopal, I. Iwasaki

Corrosion and abrasion properties of a series of chromium-containing, cast-iron balls, with Cr contents ranging from 0% to 29%, were evaluated and compared with austenitic stainless-steel and mild-steel balls. Marked ball wear tests were performed on artificial ore samples consisting of 95% quartzite, with either 5% pyrrhotite or 5% chalcopyrite, under a nitrogen or oxygen atmosphere. The electrochemical mechanism was investigated by correlating the corrosive wear with the corrosion currents obtained from potentiodynantic polarization curves under abrasion. Flotation recoveries were determined on a 95% quartzite + 5% pyrrhotite sample ground with various cast-iron ball materials under an oxygen or nitrogen atmosphere. Electrochemical results are found to be in good agreement with flotation results and with corrosive wear data obtained from marked ball wear tests.

Jan 1, 1993

By Nico Bezuidenhout, André M. van Niekerk, Jan J. G. Vermaak

This paper documents empirical evaluations of geochemical data that was recorded during a seven year pilot scale experiment. The experiment was aimed at assessing the effectiveness of natural soil covers for rehabilitation of coal discard facilities. Ten test cells were constructed using different natural soil cover materials and configurations. Results of the evaluation indicate that, although a pH breakthrough was not recorded for the single layer soil cover cells as was the case with the uncovered cells, single soil covers were not effective in preventing ARD oxidation processes. Multi layered soil covers were found to be able to create anaerobic conditions leading to a reduction in ARD oxidation processes and an improvement in leachate quality.

Jan 1, 2000

By Ezra L. Kotzin

Foundry sands used to make molds and cores have been very important to foundrymen since metal casting began hundreds of years ago. They are now used in two basic ways, either in an uncured green state, grain-bonded with clay, or in a set cured state achieved with sand that, mixed with resins or oils, is cured by baking or by chemical reaction. The term sand, as generally used in foundry applications, may best be defined as material composed of granular particles of mineral matter, ranging in size from 0.5 to 2 mm in diameter. The particulate nature of the material may be the result of natural disaggregation or result from crushing and screening of rock or ceramic materials; crushed and screened products are sometimes referred to as "manufactured sand." Based on their origin, the raw materials for foundry sands will vary in grain shape, grain composition, relative surface, grain size, and grain distribution patterns. These properties, in addition to their chemical analyses, sintering point and expansion characteristics play an important part in the choice of sands used as the base molding or core aggregate in metal casting. Sands with different origins may be blended to produce specific compositions and grain size distributions. Early raw material requirements based on silica sand were simple, but as sand/core/mold technology became more sophisticated and binder technology continued to be developed, the physical properties of foundry sands became more critical. Silica sand is composed of quartz, along with, in most cases, small amounts of feldspar, mica, clay, and other common minerals. Although silica sand is still by far the most widely used base material in production of molds and cores used in metal casting, other natural mineral sands have their own unique characteristics and fill an important niche in special applications. As a result, the term sand, as applied to raw materials used in metal casting, has been logically extended to include granular materials composed of a group of minerals other than quartz. With increased use in advanced foundry technology, natural sands composed predominantly of zircon, chromite, staurolite, or aluminum silicate minerals and of granularized chromite or olivine, have become more than just alternate materials and are now commonly classified as sands when the grains are sand-sized. Foundry sand may therefore be considered under two categories: silica sands and non-silica sands.

Jan 1, 1994

By S. K. Sharma

The Bureau of Mines' rapid method of dewatering fine-particulate slurries uses extremely high molecular weight polymers. These polymers form large, strong flocs which can be dewatered by sieving or sedimentation. However, sometimes these flocs deteriorate rapidly if water is not removed immediately. During field tests, clay slurries have been encountered that could have been dewatered economically if it were not for the rapid floc deterioration. A kinetics study was conducted to determine the rate of kaolin-PED floc degradation in which polymer addition, to bring the flocs back to their original condition, was used to determine the extent of floc decay. Results showed that the amount of polymer added, to replace polymer lost by spreading, was less for the lower PEO concentrations. For this clay-polymer system, floc breakage as judged by polymer additions followed first order kinetics. It was also found that the addition of fluoride ion stabilized the kaolin flocs.

Jan 1, 1992

By Paktunc. A. Dogan, Nand K. Davé

Unsegregated pyritic uranium mill tailings from Elliot Lake, Ontario, with and without limestone amendment, were subjected to column leaching experiments for the purposes of predicting the onset of acidic drainage and the magnitude of metal and radionuclide release under various treatment and control strategies. The unamended tailings produced acidic drainage after approximately one and a half year. The tailings mixed with various grain-sized limestone did not produce acidic drainage during the study period. The tailings consist essentially of quartz, K-feldspar, muscovite and pyrite. The unsegregated tailings amended with very fine limestone displayed the least amounts of pyrite loss whereas those without limestone amendment had the greatest pyrite losses. Predicted onset of acid generation varied from 16 to 75 years for the top sections and in most cases greater than 100 years for bottom sections of the unsegregated tailings with limestone amendments. Unsegregated tailings mixed with fine- and very fine-grained limestone proved to be the most effective in controlling or delaying the onset of acidic drainage under unsaturated conditions.

Jan 1, 2000