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By R. C. Freas

Limestone is a basic raw material in the production of cement, lime, a wide variety of industrial products, and a significant percentage of the crushed stone produced in the United States annually. It is used in fluxes, glass making, mineral fillers, environmental applications such as flue gas desulphurization and water treatment, soil conditioners, animal feeds, and as a construction aggregate. This presentation provides an overview of limestone distribution in the United States, it’s production, the variety of products produced, and a brief review of the primary uses for limestone.

Jan 1, 2006

By Bobby G. Wixson

The computer aided mapping of lead concentrations in soil has been carried out around the Doe Run (formerly AMAX-Homestake Lead Toilers) primary lead smelter near Boss, Missouri, through a cooperative Missouri Research Assistance Act program between the lead industry and the University of Missouri. As a part of this research a sequential extraction method was also developed to analyze and determine the various species of lead in the vicinity of the smelter as to possible sources which would suggest pertinent environmental control measures. Practical applications of this data-based scientific approach will be presented.

Jan 1, 1988

For processing plant design it is essential to develop a consistent material and (usually) energy balance as a basis for equipment sizing. This paper discusses techniques for consistent material balance generation, from hand calculation, through spreadsheets to specialised computer programs and general purpose simulations. The appropriate matching of techniques to problem complexity is considered, as are some possible trends for the future.

Jan 1, 1991

By M. T. Ityokumbul

The liquid phase mixing in Western Research Centre (WRC) pilot plant flotation column with diameter of 0.76 m has been characterized using a salt tracer. The process variables studied were gas and liquid flow rates. The response of the column to a tracer pulse input was monitored at three axial and two radial locations. For all the experimental conditions investigated in the present study, radial and axial concentration gradients were not observed. It is thus concluded that the 2 tph flotation column is behaving as a well mixed tank. This finding is consistent with the observed poor recoveries of coarse fractions in the column flotation circuit. Based on the findings of this report, it is recommended that several schemes of reducing the backmixing be implemented and evaluated for their effectiveness in improving the column recoveries.

Jan 1, 1994

In April 2012, work started on one of the most ambitious construction projects of Austria?s ÖBB-Infrastruktur AG ? the New Semmering Base Tunnel. Scheduled for completion in 2024, the 27.3 km (17 mile) tunnel through the Semmering range will cut the journey time on the south railway connecting Lower Austria and Styria. Before con-struction can begin at the entrance portal and tunnel bores, the work concentrates on the above ground sections with the clearance and excavation of the entrance ramp site. The slope is currently being excavated by the Baubeteiligungsge-sellschaft m.b.H. BBG-GRAZ. The cut face is shored up with shotcrete and permanent self-drilling anchors produced by Minova MAI, an economical bolting solution for softer rock formations. After completing the surface construction work, the twin-bore, single-track tunnel will be cut through the Semmering by conventional and continuous excavation beginning in 2015. Once completed, the New Semmering Base Tunnel will be one of the longest rail tunnels in Austria. It will act as a vital link on the route crossing Europe?s heartland from Northern Germany to Italy, which currently has to climb the steep Semmering pass between Gloggnitz and Mürzzuschlag on a historic mountain railway recognized as one of the UNESCO World Heritage sites. The old route imposes considerable limitations on heavy freight trans-port, and passenger trains have to slow down to a speed of around 50 kph (31 mph). The New Semmering Base Tunnel will bypass this bottleneck and cut 30 minutes off the journey time between Vienna and Graz. It represents a particular advantage for freight traffic, since the new route?s minimal incline of 8.4 percent removes all obstacles for even heavy freight trains.

Jan 1, 2013

Introduction The frigid regions of Canada's high arctic islands are well-known for major oil and gas explorations. But mining leads the way in development. Cominco Ltd.'s Polaris mine is in its second full year of commercial production, and outstripping the rated production capacity foreseen by its planners. The Polaris mine is located on the shore of Little Cornwallis Island, near the settlement of Resolute Bay. The mine property is compact. It occupies about 3 km2 (0.5 sq miles) of the vast Arctic landscape. A number of mining and technological firsts were necessary to bring a mine into production at this 76° North latitude. Development constraints that had to be overcome included climate, remote location, and the limited ice-free shipping season. Construction of the entire process plant and ancillary facilities took place on a barge in the South where labor and supplies are plentiful. The plant was towed through ice-strewn waters to its permanent location at the mine site 1450 km (900 miles) from the North Pole. Freighters moved the first shipments to the South during ice break-up in late summer 1982. Most of the zinc concentrate is sold to European smelters. The remainder is tolled at a custom smelter in Europe, and the resulting metal is sold by Cominco. Lead concentrate is sold to European smelters. The mine was designed to produce 177 kt/a (195,000 stpy) of zinc concentrate and 41 kt/a (45,000 stpy) of lead concentrate. Actual production in 1983 was considerably greater, with both mill throughput and feed grades being higher than forecast. Production was 217 kt (239,300 st) of zinc concentrate and 51 kt (56,300 st) of lead concentrate. Average milling rate was 2.3 kt/d (2500 stpd), well above the designed capacity of 2.1 kt/d of (2300 stpd). Arctic Climate Extremes The climate is typical of the Arctic: very dry with short, cool summers and long, cold winters. From November through February, there is continuous darkness. Continuous daylight prevails from April to August. Precipitation is light, rivaling the Sahara desert at about 127 mm (5 in.) of rain and snow a year. An almost continual wind forms deep snow drifts against any obstacle on the ground. Temperatures range from a winter low of about -50°C (-58°F) to a relatively pleasant 15°C (59°F) during sunny days in August. Freeze-up begins in September and ice thickness increases from less than 0.3 m (1 ft) in early October to a maximum of about 2.1 m (7 ft) in May. The permanently frozen ground extends to a depth of about 427 m (1400 ft). Only a few inches of surface ground thaws in the summer. Exploration Activity Zinc-lead mineralization was

Jan 10, 1984

By Scott G. Britton

Planning is a management tool used to solve problems and provide data and decision alternatives for company growth, profitability, and direction. Strategic planning is defined as the efforts needed to accurately measure the risks of obtaining a result from future actions given a finite number of outcomes. The techniques of strategic planning are being applied more and more to underground mine design as a result of the fierce market conditions underwhich the industry is facing today, and the conditions they will likely face in the future. The objectives of strategic planning are centered on the ability of the operator or company to manuever its limited resources to the best position available under the given future scenarios. This paper briefly examines the most popular techniques for accomplishing these objectives, how these techniques fit into the current mine management decision-making, and what results to expect from these techniques in planning efficient underground mines.

Jan 1, 1985

By Jr. Winters

The United States continues to be the largest producer and consumer of copper in the world. Table 1 on the following page shows several production statistics for 1974, the most recent year which the non-communist world copper industry might consider a good year, and for 1976 and 1977. In 1974 an estimated 24 percent of the non-communist world's newly mined copper was mined in the United States, and. 87 to 89 percent of that was from the western porphyry coppers. In 1976 U. S. new mine production was down to 22 percent of the non-communist world's newly mined copper, and the percentage of U. S. new mine production supplied by the porphyry coppers had risen to 89 to 91 percent. In 1977 the statistics remained the same as in 1976. U. S. porphyry copper production represented about 65 percent of U. S. refined copper consumption in 1974, rose to 75 percent in 1976, and dropped back to 61 percent in 1977 as imports of foreign copper into the United States began to swell.

Jan 1, 1978

By T. P. Weldum, W. Conger

"The objective of the study conducted by the authors is to determine what media size(s) addition will maximize any given plant ball mill’s grinding efficiency (Fig. 1). The functional performance parameters “mill grinding rate through the size of interest,” and “cumulative mill grinding rates” from both plant and smallscale tests are applied to this task. A plant media sizing methodology, and industrial case studies, are provided.BackgroundA previous article (“Ball mill classification system optimization through functional performance modeling,” Nov. 17, McIvor et al., 2017, Mining Engineering) described circuit classification system efficiency (CSE), equal to the percentage of coarse (plus circuit P80 target size) material in the ball mill. It can be measured and then increased through pump and cyclone adjustments. By so transferring the application of ball mill power from fine (minus P80 product size) to coarse material, circuit efficiency is increased and overgrinding is decreased.The other factor that determines overall circuit efficiency is how well the power that is applied to the coarse material grinds it. This is affected by design and operating variables like the media sizing and mill percent solids. From circuit functional performance (McIvor et al., 1990):Circuit production rate of new fine material (t/h) = Power applied to coarse material (kW) x Mill grinding rate of coarse material (t/kWh) (1)The power applied to coarse material is the total mill power multiplied by the CSE. Therefore:Circuit production rate of new fine material (t/h) = Total mill power (kW) x CSE (%) x Mill grinding rate of coarse material (t/kWh) (2) Production rate, mill power and CSE can be measured during a plant circuit survey. The mill grinding rate of coarse material is then calculated. At the circuit target P80 size, this is the mill grinding rate (of coarse material) through the size of interest. The objective is to maximize this rate. The mill grinding efficiency can also be calculated by taking the ratio of the mill grinding rate over the material’s grindability as measured in the lab. Mill percent solids optimization has thusly been achieved (McIvor et al., 2000). For media sizing, maximizing the mill grinding rate on a given ore is equivalent to maximizing the mill grinding efficiency. Ores of different grindability will be part of the discussion."

Jan 11, 2018

By William L. Barnes, Maurice Leiser

INTRODUCTION The literature on project management considerations and techniques for large rail rapid transit projects in mid-1979 was fairly large and getting larger. UMTA was establishing special organizational elements to deal with the subject as it related to those properties requesting capital assistance, and comprehensive project management plans were being requested from those properties as an early step to build confidence in UMTA that the particular project could be planned, designed, and executed efficiently and effectively, thereby using critically short capital assistance funds to best advantage. In the late 60's and early 70's, the choices of models for heavy rail construction would have been quite limited.., and perhaps much simpler than was the case in 1979. One of the writers was with an agency in 1979 in the process of finalizing its organization for project implementation after several years of study and had the opportunity to review the experiences of others at length, presumably to build on the success and to try to avoid the pitfalls and failures. The properties that were surveyed all reported more or less success stories. One could only conclude that there are many ways to organize for a major transit (construction) project and that there is a great variety of viable management structures, but it seemed that chances for success were best where the executing property had prepared a comprehensive project management plan, then resolved to follow it. Perhaps more important, a commitment or prior approval had been sought from UMTA as to the validity of the project management plan, and the property was allowed to proceed without detailed prior UMTA review or approval of all specific intermediate steps. Most important, however, an early overall UMTA funding commitment had been obtained that permitted some reasonable expectation of the rate of funding, perhaps by commitment

Jan 1, 1981

By Robert M. Dreyer

Although lateritic deposits have long been a principal source of bauxite and are becoming an increasingly important source of nickel, the problems in the evaluation of such deposits are not generally understood. In the evaluation of lateritic bauxite and nickel deposits, there are many similarities, but there also. are significant differences. It has long been recognized that laterites with commercial concentrations of trivalent metals represent the ultimate in the intense leaching of tropical soils. Any factors which effect-the rate of soil leaching will effect the form of local lateritic concentrations. Although the most intense leaching generally occurs on somewhat elevated areas of gentle relief where there is a free downward flow of rain water, the- effect of local rock structures in effecting varia¬tions in soil metal concentrations has-not been well understood - primarily because the laterite forms a masking blanket over the rocks from which the laterites were derived. All of the-factors which facilitate downward movement of water may effect greater surficial concentrations of trivalent metals. Such features as zones of fracturing, zones of greater rock permeability, and areas of karst topography may, therefore, be responsible for greater leaching. The variations in rock structures and the vagaries of ground water flow pat¬terns impart, to the laterites, rapid lateral and vertical variations in thickness and metal concentrations. Because of such rapid

Jan 1, 1970

By E. T. Sugar

English China Clays, the world's largest producer of China Clay, has its main production capacity in the South-West of England, where a complex of pits, refining plants, dryers and ports covers an area of approximately 100 square kilometres. The possibility of a computerised information network was first considered in 1980. The system was required to provide information at the central level and also at local plant level to improve co-ordination and control. Immediate access by any authorised user, and flexibility of interrogation were important aims. A small micro-based prototype system was implemented in 1981, and later that year development of the mainframe system commenced. This latter system will provide at least one terminal in every works location and will allow inter-communication of laboratory test data as well as detailed stock levels and production data. An integrated system for order processing will allow stock levels to be monitored in relation to anticipated requirements. The system has been developed by the Data Processing Department using the IDMS database package running on an ICL ME29 mainframe. It was decided to use microcomputers as terminals, which although more complicated because of protocol emulation allows stand-alone applications to be run on the same equipment. Those applications concerning Production Planning are outlined in the paper. Communication on the network is by synchronous transmission over dedicated lines. All data is stored on the central database with terminals accessing it in a star configuration. The system is currently partially implemented with 30 available screens at 18 separate worksites.

Jan 1, 1986

By B. P. Spigarelli

To meet the growing need for CO2 capture and storage technology, Michigan Technological University is researching CO2 capture and storage using carbonate solutions. The objective of the present study was to increase the absorption rate of CO2 into the carbonate solution without reducing the absorption capacity of the solution. This approach used a polypropylene glycol methyl ether (PPGME) as a surfactant to chemically alter the gas bubble size. Experiments were conducted to study the absorption rate of CO2 at varying surfactant concentrations of 0, 0.12, 0.24, 0.36, and 0.48 g/L. Results showed that as the concentration of surfactant increased in solution, the absorption rate also increased. The CO2 absorption rate increased from 3.45 mmol/min CO2 at 0g/L PPGME to 3.92 mmol/min CO2 at 0.48 g/L PPGME. This amounted to a 14% increase in the CO2 absorption rate with no decrease in absorption capacity of the solution.

Feb 27, 2013

By L. A. Hansen, D. L. Buffington, G. H. Beckwith

This paper reviews geotechnical engineering considerations in heap leach pad design, discusses design philosophy and provides design procedures. A brief discussion of surface water hydrology ground- water protection and other design considerations are also presented. Special emphasis is placed on projects in the arid and semiarid regions of the Western United States where annual evaporation exceeds rainfall, and where good foundation conditions are usually present.

Jan 1, 1987

By Les T. Zoschke

Over ten years ago, Modular began development and implementation of its DISPATCH System for haulage optimization in open pit mines and now has over two dozen systems in operation worldwide. The so-called 'top down' approach used in system design and implementation was deliberate. This foresight now allows addition of features which would otherwise prove infeasible - without complete system redesign. Until recently, truck and shovel operator input provided timing data needed for optimal allocation. Now, addition of a high-speed, general purpose token ring loop controller and infrared (IR) transponders to each piece of mining equipment automates these important functions. Here, we discuss new devices, systems, and subsystems comprising mining's future.

Jan 1, 1992

By Patrick Linzer

The majority of existing models describing (methane) gas transport within, and liberation from, coal structures treat these as continua wherein two main gas flow modes (diffusive and Darcy permeable) prevail, and use finite difference techniques to generate solutions to the resulting multivariate parabolic partial differential equation(s). Isotropy and homogeneity in the physical and geometric coal structure properties are often assumed, and the existence of fundamental random fluctuations in these proper- ties is not catered for. The model proposed herein does not suffer these inadequacies, and its efficiency is enhanced by the replacement of the diffusion equation by an accurate approximation. Dynamic mining activity, gas contributions made by the geology surrounding the mining seam, goafing of overlying strata and the effects of induced strain are all taken into account.

Jan 1, 1995

By B. E. Davis, D. A. Stanley, C. E. Jordan

A prototype expert advisor was developed by the U.S. Bureau of Mines to systematically offer advice on the control of a Florida phosphate operation. The PC based system receives input from remote sensors for circuit parameters such as feed rate, reagent addition, and pH and from operator entered information such as the quality of the concentrate and tailings in each of the coarse, fine, and amine flotation circuits. The computer evaluates the information using rules obtained from industry representatives and Bureau flotation experts. Recommended actions and questions are displayed to quickly guide the operator to a problem within the flotation circuit and suggest a solution. This process control system could provide more uniformity among the flotation operators and also serve as a trainer for new operators. In addition, it represents a step toward fully automated systems for phosphate flotation.

Jan 1, 1990

By Richard M. Levine

Now that the former Soviet Union has divided into 15 countries, it is necessary to analyze separately the industrial mineral position of each of these countries. Industrial mineral data The former USSR was one of the world's largest producers of industrial minerals and had some of the world's largest reserves. Production and reserve figures, however, must be qualified. Even when these figures were reported by the Soviets, it was not clear that the production figures were for products that would be equally marketable in a competitive market economy. The reserve figures are based on the Soviet system of reserve classification, which is not directly equatable with the US Geological Survey and US Bureau of Mines classifications of economic reserves in market economy countries. The Soviets reserve classification system, in terms of which reserve figures will be given, is based on the reliability of the quantity of the material in place. The Soviet system assigns each occurrence to one of seven categories A, B, C1 and C2 are considered reserves; P1, P2, and P3 are considered resources. Mining in the former Soviet Union was authorized on the basis of the reserves in place in categories A, B and C, which had to be in prescribed ratios. However, the categories A, B and C do not necessarily correspond to Western concepts of material economically exploitable under present market prices with existing technologies.

Jan 1, 1992

By T. Gouri Charan

Indian coals, which are of Gondwana origin, contain high amounts of mineral matter, wherein the extraneous material was intimately mixed in the coal matrix during the formation stage, causing a high level of impurity in the run-of-mine (ROM) material. These coals possess difficult to very difficult washability characteristics. Beneficiation of high-ash non-coking coals of India has become the prerequisite for improving the overall economics and efficiency of power generation. The use of dry cleaning systems in India for beneficiation of non-coking coals has gaining renewed interest recently. The benefit of the dry beneficiation process is to exploit the given resources while providing a more reliable and consistent quality fuel with a low operating cost. M/S Allmineral has introduced a technique for the dry beneficiation of coal, which is being tried in India for the treatment of high-ash non-coking coals. The first commercial air jig of 50 t/hr capacity was installed and commissioned to beneficiate high-ash coals of 40 x 5 mm feed with an ash content of 40%; a clean coal product of 33% ash was produced and is being used for a sponge iron plant.

Jan 1, 2011

By Melvin E. Poad

INTRODUCTION The placement of concrete by means of pumping is one of the fastest growing practices in the construction industry and is widely used in mining applications. In¬troduced in the United States in 1933, this method has been adapted to many aspects of the industry, especially where space for equipment is either limited or inaccessi¬ble. Concrete pumping offers many advantages over other methods of placement. Using pumping equipment, the concrete mixture can be transported in a single operation from a central mixing site to numerous forms in many remote locations, eliminating the need for rehandling the mixture and reducing the labor costs to a minimum. Pressurized pumping provides an extra mix¬ing and blending step, resulting in concrete of improved uniformity and greater density. In turn, this produces high compressive strength and increased durability. Various placement defects can be reduced or pre¬vented by pumping. The steady and even flow of the concrete minimizes the form distortion and delays caused by vibration problems that are common to fast dumping of the concrete mixes. Segregation, planes of weakness, bleeding, and surface faults are diminished considerably. Perhaps the greatest advantages of concrete pump¬ing are the distances and volumes that can be handled. Depending upon the equipment used, pumping rates of from 8 to 115 m'j/h (10 to 150 cu yd per hr) can be achieved, with a horizontal range of up to 460 m (1500 ft) and a vertical range of up to 140 m (450 ft). Theoretically, almost any concrete mixture could be pumped. However, consistency is an important consid¬eration for efficient operation. Mixes that are too wet, too dry, too hard, or poorly graded can cause difficulties that increase the costs. Similarly, mixes containing aggregate material that is over the maximum size or that is porous and highly absorptive can also result in diffi¬culties and increased costs. For the best efficiency, the mix formulation must have a well-graded sand and aggregate combination, with enough fines to provide flowability. If additional water is required for pumping, additional cement must be used to meet the design criteria of the structure. Each pump manufacturer can provide recommended mix formulations for the specific equipment furnished. Since the 1950s, many improvements have been made in pumping technology. Originally, only rigid steel pipe of 168 to 245 mm (6.625 to 9.625 in.) diam was used; today, both rigid steel pipe and flexible conduit are available in diameters of from 76 to 203 mm (3.0 to 8.0 in.). Improved pumps have been developed, and the introduction of power-coordinated booms has in¬creased the versatility of concrete pumping. The older and more conventional placement methods can no longer compete with the flexibility, efficiency, and econ¬omy of the pumping method, and continued research and development can only improve the system and expand its use throughout the mining industry. PUMPING EQUIPMENT The three major types of concrete pumping units currently available are the piston pumps, the pneumatic pumps, and the squeeze-type pumps. Table I provides a comparison of capacities, horizontal ranges, and vertical ranges for pumps of all three types. Piston Pumps The simplest of all concrete pumps are the piston¬type pumps; they are available from many manufac¬turers. As shown in Fig. 1, each unit consists of a

Jan 1, 1982