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By Flavio Moreira Ferreira

In mining industry, one of the simplest methods to smooth the standard deviation of a given ore controlled property is to build longitudinal blending piles. The effect of homogeneization is obtained due to the fact that an entire cross-section of the pile is reclaimed at each time. The variance of the pile output is the sum of the internal cross-section slice variance plus the reclaimed slice variance. While the first term is a tipical short-term parameter and is absorbed by the process, the second one may be or may not be absorbed. The goal of designing blending piles is to minimize the reclaimed slice variance. Conditional Simulation as described in this paper, is an alternative method to do it. It is devised to design longitudinal blending piles, taking into consideration economical, geometrical and statistical parameters of the ore to be blended, in order to estimate the resulting effect. It presents advantages in relation to other methods for its adaptability and flexibility in simulating pile performances.

Jan 1, 1992

By Ch. Roumpos

The present contribution investigates the way of applying benchmarking for large-scale open-pit mining operations based on sustainability indicators proposed by numerous institutions or groups of experts. These indicators have been developed taking into consideration the legal and regulatory framework that are in force. However, their scope is not only to declare the mining company?s compliance with all legal requirements but also to represent its economic, environmental, and social performance. In this way, sustainability indicators allow assessment of a company?s capacity to produce commodities, to meet the environmental quality requirements and to contribute to a long-term economic, cultural and social development of the local communities.

Jan 1, 2007

By Q. X. Yun

This paper presents a new approach to optimize the transportation system in open-pit mines. The new approach employs artificial intelligence, fuzzy sets, dynamic programming and CAD technique to determine the transportation system. The determination consists of 4 phases: initial selection, road alignment, final decision .and open-pit drawing.

Jan 1, 1992

By K. Eric Livo

The Front Range Infrastructure Resources Project (FRIRP) of the U.S. Geological Survey (USGS) is currently using Landsat Thematic Mapper? and air- borne-visible-infrared-imaging-spectrometer (AVIRIS) data along with planned thermal-infrared data and interferometry-synthetic-aperture radar (IFSAR) data to assess the industrial-minerals quality and quantity along the Colorado-Wyoming Front Range Urban Corridor and to characterize surrounding areas. Landsat? satellite data show synoptic views of the corridor, which may readily be used to identify potential regions of permissible terrain, such as river drain-ages, pediment surfaces, upturned lithology, and bed- rock exposures, where various types of deposits may occur. Descriptive models of these deposit types are used to define the physical features that need to be recognized and characterized. In the case of Landsat? data, the measured light is either reflected or partly absorbed by surface materials, depending on the wave- length of the light, which allows coarse mineral classifications to be made.

Jan 1, 1999

By Ernest Peters

To model the zinc pressure leach, equations have been written that describe the rates of individual reactions taking place, including (a) oxygen mass transfer, (b) ferrous oxidation by dissolved oxygen, and (c) ferric reactions with ZnS and other minerals. In the continuous process, at steady-state, these take place at the same rate, and so the equations can be solved simultaneously. Model calculations using simultaneous equations are shown in graphical form to demonstrate the effect of different variables on the leach performance.

Jan 1, 1993

By Drupad B. Desai, James G. Gallanes

A key component of the Inland Feeder Project is the Riverside Badlands Tunnel, a7.9-mile stretch subjected to high internal and external hydraulic pressures passing beneath highly eroded hills in a semi rural environment. The tunnel presented significant design and management challenges to the project team. This paper describes the formula for project success used to manage the design of this complex pressure tunnel, from team member selection to the completion of all contract documents, on schedule and below budget. The project team dealt with sensitive regional and local community issues and won the trust of the community. The team included participation by senior management and recognized experts from inception to finish. The team worked diligently to build quality into design and adopted a claims avoidance approach to management and preparation of documents.

Jan 1, 1997

By I. K. Kapageridis

Environmental management and planning requires the integration of large volumes of disparate information from many sources and the analysis of this information with efficient tools for assessment and evaluation. Effective methods of communication that allow interactive participation in the planning, assessment and decision-making processes are also very important. The VULCAN software package from Maptek (Pty) Ltd comprises a large number of 3D graphical tools within an interactive 3D interface called ENVISAGE. These tools are designed and developed to help engineers and scientists to identify and solve environmental problems. The combination of VULCAN 3D Software and the I-SiTE 3D Laser Imaging system leads to powerful solutions for environmental management. This paper presents the capabilities of this integrated system and its applications for environmental management.

Jan 1, 2002

By Frank J. Hirner

Economic open-pit and surface mining often call for ever increasing volumes of lower grade materials. So it is important, often critical, to develop precise expense and production estimates for the large electric mining shovels now in use. An electric shovel's basic application is to "shovel up" material, starting at ground level with the dipper moving up into a working face or bank. It's impractical to dig below ground level with a shovel, except briefly or in unusual circumstances. The shovel working face is "the bank," whether the material is dug from natural bed or blasted. The shovel's digging attachment, the boom and dipper handle, is built in standard and long range configurations. A standard digging attachment is normally used for loading into haulage equipment. The long range attachment is normally used for side or hack casting to a spoil pile. It is also used fir loading into haulage equipment placed above shovel ground level, as in some coal loading applications. Shovel clipper size and hauler capacity should he matched so that a hauler can he loaded in three to four shovel work cycles. Five cycles is usually the limit of good practice. If fewer than three cycles are required, the hauler is too small. More than five cycles indicates possible excess harder waiting time for loading, or shovel waiting time for too few haulers. Full dipper loads, including the last dipper or ''pass, " are essential for economical shovel and hauler match. Consistent need for a final partly full dipper to fill the hauler shows an improper match between the two.

Feb 1, 1981

By S. Kesler

Rössing Uranium Limited has operated since 1976 a large open pit uranium mine and extraction plant at a remote site in the Namib desert, South West Africa/Namibia. The geology (Berning, I., et al. Economy Geology) and the technical aspects concerning mining, grade control and metallurgy have previously been described (Rössing Uranium, Mining Magazin and Whyllie, R.J.M. "Rössing Uranium reaches rated production", World Mining). The improvement of leach 'extraction has been reported in 1984 (Kesler, S.B. et. al. "Uranium extraction at Rössing") and the installation of a central process control system has been described (Kesler, S.B. et al. "The introduction of a central process system at Rössing"). At the beginning of 1983 a decision was made to develop a computer system for metallurgical plant optimisation which included mass and volumetric balances, analytical assays for up to 5 chemical elements and the costs for the major consumables. Within 10 months this computer system was developed and implemented. A large number of test runs were made and computer studies were undertaken. The metallurgical division now has a scientific tool for production; planning for actual comparison with plant results and for strategic investigations and decision making.

Jan 1, 1986

By K. N. Han

A kinetic model for the batch leaching of various metals using different lixiviants was developed. The overall material balances for the reactants and products at the solid/ liquid interface were formulated for various types of heterogeneous reactions at the interface. The solutions to these mass balances are identified analytically, as well as numerically. Applications of these numerical solutions to various leaching systems using rotating discs or powders are discussed. The metal-dissolution systems addressed include cobalt, nickel and copper in acid, cyanide and ammoniacal solutions.

Jan 1, 1996

By R. N. Tempel, M. Lengke

Arsenic sulfide (orpiment, realgar, amorphous AsS and As2S3) oxidation rates were measured in mixed flow reactors at pH-2 and at temperatures of 25 ° to 30 °C. The measured oxidation rates for arsenic sulfide solids by dissolved oxygen are in the range of 10-11 to 10-10 mole m-2s-1 after being normalized to final surface area. The order of arsenic sulfide oxidation rates decreases at pH-2 from amorphous AsS > realgar > orpiment > amorphous As2S3. Compared to pyrite, arsenic sulfide oxidation rates are approximately 1.5 to 15 times slower than pyrite oxidation rates at pH-2.

Jan 1, 2003

By K. J. Henderson

INTRODUCTION Shrinkage mining at Inco Ltd.'s Crean Hill mine can best be defined as a horizontal breasting method utilizing the broken ore for the mining floor and to provide wall support, with draw from a series of boxholes or draw¬points at the base of the stoping block. In choosing to shrink a given block of ore, the initial investigation centers on the ore configuration and grade, the expected ground conditions in the stoping area, the expected profit compared to alternative mining methods, the future production requirements, development lead time, the availability and type of equipment in the area, and the availability of experienced miners. These factors are weighed against other mining methods and shrinkage mining is chosen when the advantages outweigh the dis¬advantages. These will be discussed in more detail later. At Inco Ltd.'s Crean Hill mine, shrinkage mining makes up 17% of total mine production and is decreasing due to the advent of advanced blasthole techniques, notably in-the-hole drilling. Shrinkage is an adaptable mining method that is currently employed in narrow irregular ore zones, as undercuts for in-the-hole blast¬hole stopes, in ore bodies that do not extend from level to level, and in areas where quick production is required with a minimum of capital outlay or minimum develop¬ment. Two major types are currently in use which are classified on the basis of type of draw system employed. These are the utilization of load-haul-dump (LHD) equipment drawing from drawpoints, and the slusher and train method drawing from boxholes into a slusher trench and loading into a train. A third method being phased out is drawing from chutes directly into a train. In all three methods the actual stoping operation remains the same. In the initial planning of a mining block, the ore body is first located using an exploration diamond drill¬ing program. This is essentially done at a 130-m (400¬ft) spacing and it gives an indication of the amount of ore, grade of ore, the configuration of the ore body, as well as other geological features such as ground condi¬tions which will affect future mining. This drilling is done from an exploration drift 165 m (500 ft) long in the hanging wall and covers a vertical extent of 330 to 670 m (1000 to 2000 ft). However, these data are not accurate enough for detailed planning. When the de¬cision has been made to mine, a preliminary develop¬ment drill drift is driven in such a position that it can serve the dual purposes of allowing the ore body to be drilled off in detail, or of later serving as a haulage or access drift. Diamond drilling from this drift is usually on a 15-m (50-ft) grid spacing and gives adequate information for detailed planning. Utilizing the drill data, a decision is made on the mining type. For a shrinkage operation, the stoping block is ideally 49 m (150 ft) in length and a maximum of 13 m (40 ft) in width. Lengths of 65 m (200 ft) are considered a practical maximum because of the length of time the back of the stope remains open during the min¬ing of a cut. A minimum length of 13 m (40 ft) is used because the amount of time spent in opening a new cut increases in comparison with the total stoping time. The maximum width of 13 m (40 ft) is used because ex¬perience with the ground indicates that generally stope backs tend to be unstable over greater widths. However, widths of 33 m (100 ft) have been mined. A minimum width of 5 m (15 ft) is used to allow an effective draw, but in unusual cases, a width of 3 m (10 ft) has been mined successfully. The dip of the ore should not be less than 1.04 rad (60°). Angles flatter than this will not pull properly resulting in inefficient mining because of ore hang-ups on the footwall side of the stope and the need for large stagings on the hanging wall. In considering shrinkage, mining ground conditions play an important role. Strong shearing, cross faulting, or dikes are avoided. These usually cause dangerous mining conditions and an alternative safer mining method which will give adequate support to these adverse ground conditions is employed. Production requirements are taken into considera¬tion when planning a shrinkage mining program. In it¬self, shrinkage mining is capable of producing ore in a relatively short time with little capital development. If quick production is required, this method can produce ore rapidly as all that is required is that the draw system be completed and the miners with jacklegs and stopers produce a limited amount of ore. The obvious disadvan¬tage is that not all the ore broken can be pulled from the stope immediately. However, a mining horizon with sev¬eral shrinkage stopes in different stages of production can adequately maintain scheduled tonnage require¬ments, the cycle being stopes under development, stopes actively mining, and stopes completed and pulling. When the decision has been made to use shrinkage mining in a given block, the haulage and draw system is driven. The proximity of the orepass system dictates whether the system is to be a LHD operation or a slusher trench operation. If the orepass system is in close prox¬imity to the stoping block, LHD equipment is employed because of its ability to operate efficiently over short haulage distances. A long tram to the orepass usually dictates a slusher trench operation with haulage by train. Internal orepass systems are used effectively with LHD equipment with a load-out and retramming taking place on a lower horizon. In addition, stoping blocks in older areas of the mine are developed track because of the capital cost involved in converting an existing level to trackless mining. DRIFT DEVELOPMENT USING LHD EQUIPMENT The haulage drift for a draw system using LHD equipment is driven parallel to the ore body in the foot¬wall at a sufficient distance to allow an 11.5-m (35-ft) drawpoint to be driven into the ore (Fig. 1). The actual position of the drift depends entirely upon the ore con¬figuration and the drift size depends on the equipment to be used. Drift sizes of 4.6 x 4.1 m (14 x 121/2 ft) for an St-4 and 3.8 x 3.6 m (111/2 x 11 ft) for an St-2 meet company and government clearance standards and allow sufficient space to accommodate a ventilation pipe. The

Jan 1, 1982

By N. P. Reddy, Y. J. Wang

This paper describes an experimental setup for multiple fan ventilation systems at the ventilation laboratory of the West Virginia University Department of Mining Engineering. Housed in a 30-ft x 70 -ft room, the experimental setup consists of three 18-in., variable-speed, axial flow fans; an 18-in. -diam, fiberglass tubing; associated fittings for arranging networks; and a picot-tube measuring and data-acquisition system. The fiberglass tubing and fans can be organized into non-planar networks of two or three fans. The setup is mainly designed for studying the characteristic curves, operating points and fan stall for multiple fan ventilation systems.

Jan 1, 1993

By R. Schmidt

The computational fluid dynamics (CFD) technique was used to analyze and optimize the design of the dynamic air classifier integral to Raymond® Bowl Mills. Flow patterns and particle behaviors were modeled in the RB Bowl Mill equipped with various classifier designs. These CFD simulations resulted in the development of a hybrid turbine classifier that has now been field-tested, yielding significant improvements to both mill throughput and product size distribution. This paper demonstrates the viability of CFD as a tool for air classifier design and as a technique that can be extrapolated for use with other pulverizer and classifier arrangements.

Jan 1, 2004

By A. Perelli Cippo, R. Granata, D. A. Bruce

During the last few years, significant advances continue to have been made in aspects of grouting technologies used for ground treatment in advance of tunnelling. In permeation grouting, fundamental researches have continued into improving the penetrability characteristics of cement-based grouts. The twin advantages of field regrinding normal grouts to reduce cement particle sizes, and incorporating special additives into stable grouts, are now being systematically exploited in major soft ground tunnelling projects in Europe. The methodologies of jet grouting continue to be developed with special attention being paid to qa/qc issues, reducing unit production costs, and improving predictive capabilities for subsequent settlements.

Jan 1, 1993

By A. I. A. Salama

A computationally efficient technique for generating a balanced set of density or size separation data is developed. The technique proposed utilized minimization of a modified form of error squares to generate the optimum estimates of outputs mass yields (splits) and balanced direct mass distributions of feed and outputs. The estimated separation data set satisfies mass balance conditions of the streams mass distributions around the separator. The technique proposed avoids the generation of small negative values for the estimated feed and outputs direct mass distributions. Actual data are used to demonstrate the technique proposed.

Jan 1, 1996

By John C. Edwards, Robert C. Bates

Modeling uranium mine radiation control methods and natural environmental radon variations is an extremely complex endeavor. A number of authors have examined particular facets of the problem and have proposed models for their area of interest. Bureau of Mines personnel brought together many of these individual studies, and from them have attempted to develop a coordinated plan for modeling radon daughter concentrations in the uranium mine environment. This approach is described.

Jan 1, 1981

By S. D. Thompson, G. T. Lineberry, A. J. Basu

Conveyor belt haulage has become the preferred mainline transport method in underground coal mining, especially for multi-unit mines. Proper designs for belts (width and speed) and surge bins (placement, capacity, and discharge rate) are necessary to achieve efficient mine haul- age. Two computer simulation models, CMBCS and BELTSIM, available for designing these parameters were compared. These comparisons included modeling, input data requirements, statistical flexibility, accuracy of simulated loading, and execution time.

Jan 1, 1991

By R. W. M. Lai

The study of flotation kinetics was first reported by Garcia-Zuniga1 in 1935. Since then, literature on the subject has grown with the time. 2-19 Although there is an abundance of flotation kinet¬ics models available in the literature to describe flo¬tation systems, they are mostly of academic interest and are seldom applicable for use in the industrial environment. Several reasons contribute to the wide gap in the industrial -application of the academic models. These include: 1) the lack of generality in the model, e.g., the model is limited to certain size ranges; 14 2) the academic models involve complicated mathematics; 5,6,10,11 3) confusion about the order of the flo¬tation rate, e.g., several authors proposed a first order rate model, 1,15,16 whereas the others propagated a second order rate model: 2,17,18,194) the use of an unrealistic rigid value, such as the use of a maximum recovery of 100%, 5,8,19 which is unrealistic in industrial operations; and 5) the use of graphs that confuse the reader rather than interpret information. 2,3,10 This paper intends to introduce a simple and easy to understand empirical flotation kinetics model along with a way of presenting the model in an informative graphical form, which should stimulate the interest of other practical engineers to become concerned with practical application within the mineral industry.

Jan 1, 1982

By M. S. Klima

Proper analysis of washability data can lead to the development of a maximum yield coal preparation plant flow sheet. Simulations, as simple as spreadsheet mass and water balancing, are important in examining yield maximization and middlings liberation. Key to such attribute tracking flow sheet simulations is the distribution model, expressing the probability of a species reporting to the product stream. There are many such models in the literature. This paper examines a functional form that can represent or fit most of the proposed distribution functions.

Jan 1, 1997