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By Frank H. Skelding

A new, large mine is about to be born. Many years and millions of dollars have been invested in exploration. An orebody has been found and proven. All necessary political and legal work to establish rights and conditions for development are complete. The feasibility studies are favorable. Financing has been arranged. Board approval has been given to proceed. The time has come to engage a contractor to design and build the new facilities in a location, as is the common case today, far re¬moved from the centers of advanced technologic development where the minerals will ultimately be used. A select list of Engineering and Construction (E&C) companies is asked to prepare proposals. At this point the common viewpoint among mining companies is that the company's sole remaining problem, a major one to be sure, is to select qualified contractors to design and build the project at the lowest cost and shortest time possible so that production can start generating a return on investment. The purpose of this discussion is to explore the viewpoint of the large E&C contractor toward such projects. It differs in important ways from that of the client mining company and it is these differences and the reasons for them that must be understood by the client if severe difficulties and misunderstandings with the contractor, starting at the beginning of contract negotiation and continuing through design and construction to final startup are to be avoided or minimized. Often enough, the difference is in degree, not kind, which only serves to obscure the fact that a difference exists.

Jan 1, 1975

By Richard D. Zigmond

In this paper, a computer program that has been developed for determining the capital and operating costs for coal preparation plants is described along with its applications. The logic of the computer program is based upon the results of a survey of existing preparation plants, operators, plant contractors, equipment manufacturers, and consulting firms. This survey provided information on plant performance, order-of-magnitude costs, and costing procedures. Additionally, an extensive cost data file for the major capital equipment in coal preparation plants has been developed. Using the washability data and the computer program outputs, the cleaning costs per million Btu can be calculated. Details about the program and its applications can be found in a report by the authors (Zigmond et al., 1979).

Jan 1, 1981

By D. B. Stephens

Milling operations throughout the world have created vast amounts of waste by-products, or tailings, which are often disposed on the land surface. The wastes may be disposed behind dams, on untreated ground, or on compacted clay or synthetic liners of impoundments and trenches. Often one of the principle concerns of environmental regulatory agencies is whether seepage from the waste pile could move through the vadose zone to the water table and possibly contaminate an aquifer. The seepage may be generated by the drainage of liquids initially deposited along with the tailings or by infiltrating meteoric water which leaches solutes from the tailings. The purpose of this article is to discuss some of the commonly held assumptions regarding storage of seepage wastes in the unsaturated zone. The significance of recent studies of water movement in dry climates which pertain to tailings site selection will be presented. The paper is relevant not only to seepage from impoundments at mill sites, but to many other fluid waste impoundments as well in part this article reinforces earlier work by Stephens and Siegel (1980) and an excellent review paper by McWhorter (1985). The present report addresses considerations in porous media; for a discussion of the effects of fractures and anisotropy in the unsaturated-zone, refer to the paper by McWhorter (1985).

Jan 1, 1985

By E. C. Wilson

The knowledge concerning the lubrication of open gearing for mining machinery has contained many unknowns and at its best has relied to a great degree on a "Rule of Thumb" procedure. It will be within the scope of this paper to explain what we have learned to date and what must be learned in the future. The results in the lubrication of open gearing have spanned the spectrum of unsatisfactory to satisfactory. With the advent of larger mining machinery, we are faced with the necessity of a more thorough knowledge of open gear lubrication. We have avail- able, better steels for the gearing, advanced technology and machinery for cutting proper tooth profiles, and better means of aligning the teeth in the gear train. This has made it possible to transmit more horsepower through the same size gear set than ever before, if we have the proper lubrication to complement the factors previously mentioned. We have set up computer programs which can calculate the data fox the tooth forms, the correct operating center distances, the contact stresses, the bending stresses, and the PVT factor of the gear teeth. This program does not, at the present, have sufficient data available to calculate the type of lubricant which should be used.

Jan 1, 1968

By Charles E. Stack

There are several ways in which to classify refractories. The most suitable one is based on their general composition or raw material content. The categories are: 1. Aluminosilicate brick which include the fire clays and alumina and high alumina raw materials. 2. Basic brick which includes magnesia and chrome ore alone and in various combinations. 3. Silica brick which uses gannister or high purity gravels and sands. 4. Insulating brick are generally of the aluminosilicate type but may be most all refractory raw materials. 5. Special refractories are made from raw materials of zircon, zirconia, ultra high alumina, silicon carbide, fusion cast products, chromic oxide, carbon and graphite. The raw materials that make up these different categories are what we are briefly going to consider. Emphasis is placed more on the most important raw materials.

Jan 1, 1976

By E. M. Haynsworth

The disposal of phosphatic clays has presented a problem to the phosphate industry since the mining of phosphate rock first began. As the flotation process was introduced in the late 1920's, the problem of clay disposal was increased significantly since clay is present in proportionally greater quantities in reserves yielding flotation concentrates. Because of their physical character and the tremendous surface area per unit volume, these clays have the characteristic of retaining large volumes of water as they are slurried during processing. The phosphatic clays with which we are dealing consist primarily of apatite, wavellite and montmorillonite. In the beneficiation process, we remove the -150 mesh material as waste. However, the particles are essentially smaller than -325 mesh, and more than 70% are smaller than three microns. The disposal of clay and the recovery of a portion of the water require settling areas with a capacity ranging up to 2 cubic feet for each cubic foot of phosphate matrix mined. According to a recent study by the Bureau of Mines, the average cost for disposal of these wastes is 24.5 cents per ton of, product (U. S. Bureau of Mines Circular 8404). This is a major cost of phosphate rock production.

Jan 1, 1970

By Harry R. Dahlberg

Heap leaching is discussed as a unit process. Five factors are identified as the principal elements that can be measured and/or controlled. These are: 1. Material Size 2. Volume of solution 3. Tonnage of heap 4. Time 5. Solution concentretion. The Rate of Extraction Curves obtained from an actual heap or column tests describes the economic viability of the unit process. By analysis of these curves and the five factors end their inter-relationship it is possible to determine how the extraction rate can be increased. The practice of leach and rest used by many operators is analyzed and shown on a hypothetical rate of extraction curve. The influence of the driving force of the hydrogen ion and ferric Lon as Lixivants and its effect on the rate of extraction curve is discussed.

Jan 1, 1979

By W. C. Morgan

This paper discusses some of the problems involved in predicting the productivity of a shovel and truck fleet in a new set of operating conditions. More specifically, it concentrates on the problems of predicting the travel times on the haul and return portions of the truck cycle under new profile conditions and the prediction of the interaction effect between the shovel and trucks at the loading point. The ability to calculate the travel times for a new road profile is not new. Additional corrections of these calculated times for expected actual operation can be made. In considering the interaction between the loader and the hauler, there are two approaches that can be taken. Probably the most accurate method of predicting the shovel-truck interaction is a simulation of the step-by-step operation considering the variation in cycle times of the shovel and trucks. This is usually called a stochastic simulation and requires input describing how these cycle times vary. However, by understanding the causes of this shovel-truck interaction it is possible to make sufficiently accurate predictions with much simpler methods. For the purpose of this discussion let us assume that the problem involves trying to predict the productivity of a single shovel-truck fleet at some future time in an existing operation. Let us also assume for simplification that the new operation to be simulated has the same loading and pit conditions and the same dumping conditions as did the existing operation. Therefore, the only difference would be the difference in the hauling profile for the new operation. The problem then becomes one of predicting the change in the travel times on the haul and return portions of the cycle, and in determining the change in interaction between the shovel and trucks with the new truck cycle times.

Jan 1, 1968

By Kendrick C. Hardcastle

Although the basic techniques employed in hydraulic pumping in open pit mining have been practiced throughout the better part of this century, only relatively recently have studies of' sufficient depth and scope been conducted to improve these techniques. This paper will point out the basic techniques involved and some of the more recently discovered data concerning hydraulic pumping, Inherent in all hydraulic transportation systems apart from the consideration of transportation cast, is the outstanding advantage of slurrying the matrix at the mining pit so as to provide a lengthy and thorough soaking and washing of the material while in the pipe line and thereby reduce the necessity for washing, scrubbing and other treatment in the beneficiation plant. This is quite important in view of the constant increase in demand for a cleaner product.

Jan 1, 1964

By L. Barry Phelps

Selective placement of toxic mine spoil has been advocated as a means of reducing environmental pollution at the source. However, methods of burial to control environmental damage are not well understood. Using the finite element method, this paper investigates the burial of toxic material within low permeability packages below the water table. The effects of differing package and spoil permeabilities, anisotropy, and infiltration are modeled to provide information about their effect on the flow system. Projection can then be made which will assist in the design of the toxic spoil packages to limit the amount of groundwater flowing through them.

Jan 1, 1983

By J. K. Conibear

Since the 1948 introduction of hydraulic fill at the Sudbury Ontario Mines of the International Nickel Company of Canada, 32,000,000 tons of water-borne sandfill and 420,000 tons of portland cement addition have been placed in underground workings. Fill method mining, currently conducted at six of the ten operating mines, accounts for 28 percent of the total mines underground production. Both classified mill tailings and screened alluvial pit sand are used as fill for cut-and-fill primary mining, undercut-and-fill pillar recovery, and backfilling of blasthole and shrinkage stopes. Cemented fill, consisting of a lean mixture of portland cement, is used in areas where a stabilized fill is required to reduce dilution and aid in the recovery of adjacent pillar ore.

Jan 1, 1970

By Ben H. Daud

The systems optimization approach to mine planning has led to the adoption of a number of mathematical and computer models for short, medium and long range planning of mining operations. In the realm of open pit mine planning, the most common uses of such an approach have been in the areas of optimal pit design and planning of materials handling operations. Since a truck-shovel combination is the most widely used method of materials handling in open pit mines, a number of models have been presented in the past to analyze and optimize such systems. Broadly, these models can be divided into two categories. The simulation model, which is primarily used as an aid in analyzing the performance of either an operating or a proposed haulage system under the influence of externally alterable parameters, and the linear or integer model which is used as a tool for short or medium term optimization of the system under the operating constraints. In the first part of this paper, a brief discussion is presented of the linear/integer optimization models presented in the past, and in the second part a new model is described which is actually a combination of the simulation and the integer programming models. In its bare essentials, the model consists of an integer optimization algorithm, but the constraints are regularly and dynamically updated by incorporating the conclusions drawn from a stochastic simulation model of the mine haulage system. Since the successive optimization is performed by the mine operator who manipulates the constraints to guide the model towards the optimum, the mystical black box approach is minimized and should help in adoption of the model by the mine personnel. Also, by combining the stochastic simulation model and the deterministic integer model, some of the advantages of each are acquired.

Jan 1, 1976

By Frank J. Foster

This Paper will deal with Bucketwheel Suction Dredging and its particular relationship to mining applications. There will be comparisons with other methods of suction dredging and descriptions of two recent bucketwheel installations in the mining area. The Directory of World Dredging Fleets published in the `larch 1984 edition of World Dredging magazine shows that there are about 1.000 conventional Cutterhead Dredges listed throughout the world with 289 in the United States. There are 242 Bucketline Dredges listed throughout the world of which only 6 are in the United States. These figures are not completely accurate because several units are known to the author that are not on the list and, of course, there may be others.

Jan 1, 1984

By D. J. Crawford

The Lucerne Valley Operations of the Minerals, Pigments and Metals Division of Chas. Pfizer & Co., Inca, are located about 5 miles south of the town of Lucerne Valley, California. These operations consist of several limestone quarries, a whiting plant which produces finely pulverized limestone products, a-kiln which produces granular quicklime and lime products, and maintenance shops, warehousing, shipping, and office facilities. Construction of the Lucerne Valley plant began in 1961 as the result of a decision to utilize large undeveloped reserves of limestone in that area. Quarry development was started in the following year; and by 1965, Lucerne Valley had become the principle limestone and lime facility of the Western Operations of the Minerals, Pigments and Metals Division.

Jan 1, 1967

By J. J. Scott

Friction Rock Stabilizers, trade name Split Set*, is a new support system invented by the author and under development by Ingersoll-Rand and Lee-Norse Company. Split Sets are a substitute for standard bolts or fully grouted resin bolts and have certain advantages which are: 1. Improved safety for the miner 2. A rational design is possible based on rock mechanics principles 3. Supports can be made either to be yieldable or rigid 4. Supports can be used to build a roof beam or to suspend roof material 5. It is cheaper than the resin system and costs about the same as standard bolts.

Jan 1, 1974

By R. K. Singhal

Optimization of a load-haul system for a surface mine involves two processes. The first is proper selection of mining equipment compatible with the minesite job specifications and the second is an efficient utilization of this equipment. All things being equal optimal productivity and cost is achieved when the capacity of the hauling equipment is matched at all times with that of the loading equipment.

Jan 1, 1986

By Rodolfo V. de la Cruz

This paper describes the development of a new method and device for determining the in-situ mechanical properties of rock masses. The method involves a self-recording mechanical deformation gauge for sensing-recording she deformation of the borehole wall when loaded hydraulically. The self-recording feature of the gauge eliminates the difficult technical problem of transmitting signals over very long cables for measurements at great depths. Adopting a mechanical gauge instead of electronic, electrical, optical or grid techniques eliminates delicate instrumentation and installation problems. Moreover, mechanical gauges are inherently rugged and suitable for use in severe borehole conditions including very high temperatures. The technique was tested in limestone, basalt and granite specimen. The calculated mechanical property values for 1 the tests agree with those obtained by conventional testing methods. The self-recording mechanical deformation gauge has a minimum reading of 50 micro inches (1.27 x 10-3mm), comparable with electrical resistance strain gauges, capable of reading deformations over a range of 0.25 inches (6.35mm). The sensitivity, ease and accuracy of the method recommends it highly for in-situ rock modulus measurements.

Jan 1, 1980

By Robert S. Lehto

Zinc concentrates received in La Oroya zinc refinery are marmatitic in nature, contain about 11% iron and traces of other metal values, Figure 1 shows the zinc circuit. The calcine from the roasted concentrates is leached in spent zinc electrolyte. Major part of the impurities is iron which has been oxidized to its trivalent form, This is the origin of the zinc leach residue for which the ZILERET process was developed and so named. The impure liquor from the leach is sent for purification and thence to electrolysis- zinc deposits on aluminum cathodes from which: it is stripped, melted and cast into slabs Typical assays of zinc calcine and leach residue are given in Table 1. Metal values contained in the leach residue, without counting any value of iron, amount to roughly $130 per short ton.

Jan 1, 1969

By George A. Desborough

Marine black shales of Paleozoic age in the Western United States that exceed 10 weight percent organic carbon contain as much as 5,000 ppm vanadium, 1,000 ppm molybdenum, 1,300 ppm nickel, 600 ppm cobalt, 16 ppm silver, 7,000 ppm chromium, 18,000 ppm zinc, 280 ppm cadmium, and 350 ppm selenium. Depositional settings include: (1) continental-rise and marginal-ocean basins, (2) continental-shelf and foreland basins, and (3) cratonic-platform embayments. Most of these metalliferous organic-rich shales have not been examined for resources because of rapid weathering and poor exposures which preclude easy sampling of unoxidized rock necessary to determine actual concentration and residence of indigenous metals. Generally, the marine black shales of Paleozoic age in the Western United States are richer in metals than marine Paleozoic black shales in the Eastern United States.

Jan 1, 1982

By Sun K. Kim

Hydrometallurgical processes are not free of environmental regulations. A clear understanding of the regulations under which the minerals industry operates delineates processing requirements at early stages. This paper deals' with federal environmental regulations with emphasis on the hazardous waste regulations promulgated in May, 1980. The procedure of EP toxicity test and an example of the test are described. Brief account is given of the current trend and future outlook of regulations.

Jan 1, 1982