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By Peter Amelunxen, Kain Nugent, Brandon Akerstrom, Willem Duyvesteyn, Todd Harvey

In 2024, Capstone Copper Corp commissioned a new sulfide flotation plant at Mantoverde in the Atacama region of Chile to process copper ore at a design rate of 32,000tpd. The pyrite associated with the copper ore body contains cobalt in solid solution, with Co replacing Fe in the pyrite matrix. As per the existing sulfide flotation flowsheet most of the pyrite is depressed and sent to tailings via the cleaner scavenger tail stream. A new project considers the recovery of the pyrite from the cleaner-scavenger tails via froth flotation to produce a cobaltiferous pyrite concentrate, which is then leached via the existing dynamic copper leach pad to oxidize the pyrite and dissolve the cobalt. The cobalt is recovered from the solution by treating a bleed stream of copper SX raffinate through a continuous, counter-current ion exchange (CCIX) facility. This approach to by-production of cobalt confers numerous benefits, including reduced costs compared with alternative cobalt recovery processes, reduced acid consumption in the heap leach, increased copper production, and reduced acid mine drainage potential due to the removal of pyrite from the mill tailings.

Feb 1, 2025

By M. A. Reyes, L. Yan

Heat and humidity buildup withn refuge alternatives (RAs) may expose occupants to physiological hazards such as heat stress. The Mine Safety and Health Administration (MSHA) regulations require RAs in underground coal mines to provide a lifesustaining environment for miners trapped underground when escape is impossible. RAs are required to sustain life for 96 h while maintaining an apparent temperature (AT) below 95 °F (35 °C). The National Institute for Occupational Safety and Health (NIOSH) tested a 10-person tent-type RA, a 23-person tent-type RA, and a 6-person metal-type RA in its underground coal mine facilities to investigate the thermal environment over a 96-h period. The test results showed that mine air and mine strata temperatures surrounding an RA occupied by simulated miners (SMs) increased over the 96-h test period. The test results suggest that RA manufacturers should consider this increase in temperatures when calculating and evaluating RA components during surface and laboratory tests. The findings can equip stakeholders with additional considerations for calculating the interior heat and humidity temperature profiles for occupied RAs not tested in situ.

By Vladimir Adamek

Due to the variability of subsidence characteristics across the U.S. coalfields, it was concluded that it would be practically impossible to develop a universal predictive model for mining-induced subsidence based on theoretical assumptions. Therefore, an effort was made to find a procedure to develop an empirical subsidence predictive model based on a sufficient Mount of field data from one mining area (in this case the Northern Appalachian Coal Region). It was also thought that this procedure, if successful, could be used as the template for developing predictive capabilities for other coalfields with different subsidence characteristics given a reasonable amount of field data. It has been found, in the Northern Appalachian Coal Region, that the variability of subsidence characteristics can be expressed by a polynomial equation developed through regression analysis of the variable subsidence coefficient and derived directly from the field data. In this study, field data were obtained from 11 Bureau longwall panel studies (16 half profiles) for static subsidence and 14 panels for dynamic subsidence. The effects of lithology, expressed in the form of a variable subsidence coefficient, have been separated for each test site by introducing a correlation between hythetically homogeneous overburden and existing ithological conditions. For each longwall panel, the characteristic of the variable subsidence coefficient was defined along individual static profiles. The definition of mean values with acceptable deviations is the substance of the predictive method. The same procedure was used to develop a predictive model for dynamic subsidence, since it war discovered that the rate of longwall face advance is not a necessary functional parameter. This paper presents the theory, development, and application of the static and dynamic subsidence prediction models.

Jan 1, 1986

By Peter G. Chamberlain

The Bureau of Mines is conducting research to boost domestic production of manganese. Virtually no mining exists in the low grade and/or small deposits that occur in this Country. One large, low-grade manganese deposit located in westcentral Arizona--The Artillery Peak district--was extensively studied and sporadically mined during the 1940's and 1950's. Although manganese mining in the district has been long dormant, recent studies indicate that the deposits may be amenable to economical production by heap and/or in situ leaching methods. A conceptual design for an in situ leaching system features undercutting and blasting a block of ore, leaching with SO2, and extracting the manganese as a sulfate or oxide. Possible applications to other manganese deposits depend upon formation permeability and specific manganese mineralogy.

Jan 1, 1981

By Thomas R. Kuesel

Just south of the L'Enfant Station in Seventh Street, the WMATA system splits into two branches, each comprising twin single-track soft ground tunnels. Immediately at the beginning of the section, Interstate Route 95 crosses transversely over the alignment in open cut, removing most of the cover over the tunnels. Seventh Street spans I-95 on a bridge whose abutments and pier also cross transversely over the four tunnels, with their footings as little as 7 feet above the tunnel crown (Figure 1). Soil investigations revealed that the tunnels would have to be driven through mixed face, with a clay invert and a waterlogged sand crown. Thus, there was a good chance that the roof would fall in, leaving 1-95 and the Seventh Street Bridge in a crater. Since there was no roof that could be counted on, these were figuratively (and potentially truly) Washington Metro's Topless Tunnels (Figures 2 and 3). DESIGN ALTERNATIVES Faced with this situation, the designers considered several options, including temporary detours that would permit demolition of the bridge and building tunnels under the 1-95 Freeway by cut-and-cover methods. They also investigated structural underpinning of the bridge and freeway pavement, and strengthening the bridge abutments and center pier by post-tensioning to enable them to span over any subsidence trough.

Jan 1, 1976

The amount of hydrophobic materials constituting the mineral froth strongly influences the froth viscosity. Higher froth viscosity on the other hand can retard the drainage of physically carried over hydrophobic particles. In phosphate flotation tests a direct correlation was observed between froth viscosity and recovery and an inverse correlation between froth viscosity and grade. Phosphate flotation tests in the presence of a silica depressant indicated that higher froth viscosity is an effect rather than a cause of silica particles reporting in the froth.

Jan 1, 1992

By S. Yap, F. J. Sotillo, L. P. Irwin, F. M. Utsey

Slimes, especially clays, are detrimental to several processes in the Mining Industry. The efficiency of classification, clarification, gravity separation, and flotation decreases significantly in the presence of slimes and clays. This problem is particularly critical in the Phosphate and Sulfide Industries. To reduce the effect of slimes in mineral processing, several desliming techniques and chemical additives are used, such as sodium silicate, sodium carbonate, sulfuric acid, tripolyphosphate, hexameta phosphate, etc. Lately, the Mining Chemical industry has shift to more “Specifically Developed” reagents that offer the most efficient and cost effective performance, mainly using organic polymers. For this purpose, the Mining Chemical Industry needs to understand the crystal chemistry of minerals, the chemistry of the aqueous media, the interactions in solids-aqueous-gas interfaces, the rheology of the system, and the plant operation conditions and parameters. This paper describes the use of surface chemistry fundamentals on the design of an organic polymer capable of modifying the rheology of clayish slurries of a phosphate ore. The change in the rheological characteristics of the clayish phosphate slurries allow fine ore particles to settle faster by reducing the slurry viscosity. Thus, abetter separation of the ore from the slimes is possible using gravitational or centrifugal forces. As examples of the application of this reagent, industrial and pilot plant tests on desliming using tanks and hydrocyclones are presented. These tests showed the reduction of 32%-36% in ore losses for different phosphate ores during desliming operations, and the increase of cyclones desliming efficiency to 80%. Tests were also carried out to improve the rejection of unwanted iron bearing slimes in phosphate feed. These tests demonstrated that it is possible to reduce by 0.25%-1.23% Fe2O3content in the flotation feed product. As a result, significant economical benefits are observed with the use of this new technology without any adverse effect on down stream operations, such as clay settling or phosphate flotation.

Jan 1, 2003

By Xin Jingmin

The present trend toward concentration of mining activities into fewer sections of a coal mine and application of automation and remote control technologies favor utilization of the longwall mining method. Longwall mining also offers the potential for improving safety and productivity, better ground control and higher levels of recovery. The production potential of a longwall operation is determined by the interaction of several factors including the rate of face advance, the thickness of extraction, the speed of cutting and hauling equipment, the physical dimensions of a longwall panel, and the reliability and availability of the equipment. Some of these factors are dictated by the environment in which the extraction process is to be undertaken. Some other factors, however, can be manipulated in order to optimize the production of the system. The objective of this paper is to develop a stochastic model to simulate the production operations in longwall mining. The activities and parameters that affect the production potential of the longwall operations and the relationships between the activities are identified. An attempt is made to verify these relationships through the use of existing data. The model is then used as a computer simulator to investigate the effects of various activities and parameters on the production capacity of a panel.

Jan 1, 1983

By F. C. Appleyard

A couple of miles southwest of the town of Saltville in the western tip of Virginia is a little village called Plasterco. Gypsum has been produced in this area since about the year 1815, being originally found as small outcrops at the surface. Production in the early days was very small, and the use of the mineral was limited to that of "land plaster" or ground gypsum which was spread on the land to sweeten the soil. In the late 1800's, a small calcining plant was constructed and the production of gypsum plaster began. About this same time, the surface rock was depleted and it became necessary to begin underground mining operations in order to maintain a continuous supply of raw material. The United States Gypsum Company became interested in this property in 1909, and has operated there ever since, having enlarged the calcining mill and built a plant for the manufacture of gypsum wall-board in the middle 1920's. Production of gypsum continues from underground' mining operations, and the present mine at Plasterco is now about 1,000 feet below the surface, making it the deepest gypsum mine' in the world.

Jan 1, 1965

By James Boyd

JAMES BOYD 29.1-STAFF-AND-LINE ORGANIZATION Industrial organizations are established primarily to coordinate the activities of many individuals working toward a specific goal. In mining, the goals can vary widely, and the skills necessary to reach them likewise will vary from operation to operation. It is essential to keep in mind the principal point that an organization embodies the necessary skills which supplement each other and achieve a given objective. Those who direct such an organization are grouped together as "management" and accept the responsibilities for the regulation, administration, supervision and guidance of the enterprise. Those who comprise the "administration" and have supervisory authority are referred to as the "executives." In the early days of mining it was common for one executive to exercise virtually complete control over the entire organization, and direct its operation from a central office. However, the science of management has advanced significantly since then. Mining organization administration now allocates increased authority and flexibility to those in direct-line responsibility, and organizes competent people in specialized fields to provide supervisors with guidance where it is needed in day-to-day operations. Few mining companies today are confined to one operation. Therefore, highly developed skills can be provided in the staff which assists management. This is known as staff-and-line organization, illustrated, in general, in Fig. 29-1. Each operation requires diverse skills for the carrying out of specific functions. The acquisition and training of those with such skills is an important operation in assembling organizations. An organization normally is modified to accommodate individuals rather than being a "hard and fast" mold into which people are fitted. The modern manager is inclined to organize to minimize central direction, with delegation to line executives, providing staff whose day-to-day operations, in cooperation with line executives, coordinate a continuing drive toward the organization's objectives. The staff officers, therefore, tend to become what could be described as parts of the president's brain, dealing with specific areas requiring certain skills. They do not necessarily direct operations, but watch them to be sure that the skills which they have themselves developed can be transmitted to line operations by persuasion rather than by direct authority. The elements of management requiring staff assignments are: 1. Planning, which, at staff level, is only a coordinating activity. Planning is done at all levels in the organization. 2. Engineering. 3. Finance. 4. Control. 5. Personnel and industrial relations, which set personnel policies, including salary plans and the means of handling relations with the unions. 6. Research, which, in a modern organization, is essential to progress and needs to be overseen at the top. 7. Legal staff to see that all operations of the company are provided with sound legal advice, and that the company's policies stay within the law.

Jan 1, 1973

By A. L. Hannaford

Previous production at Spektakel was undertaken during the periods 1854 - 1888 and 1892 - 1901. During this period a total of 41,7 kt of ore grading 32% Cu was hand-sorted from 270 kt to 360 kt of ore mined. Initial open-pit mining was followed by underground mining, access being by means of an inclined shaft to the 85 fathom level. During the period 1946 - 1952 cement copper equivalent to 5,452 kt of blister was produced by leaching of oxidized ore. The Spektakel ore-body branches and coalesces both in plan and in cross-section which accounts for its remarkably complex configuration. Constituent rock-types are andesenite and various varieties of biotite diorite and of ?norite? (biotite-hypersthene diorite). Closely related spatially, and possibly genetically, but predating the above-mentioned basic rocks are bodies of biotite-bearing monzoritic rocks, locally termed shonkinita.

Jan 1, 1981

By Donald V. Fites

The evolution of open-pit mining has been rapid during the last two decades. The development of larger, more productive and efficient equipment has been one of the key factors in this open-pit advancement. Selection of the proper equipment and its correct usage is paramount to successful operation while maximizing return on investment. The quantity of material being moved prior to mining the saleable product is increasing at a significant rate. For example, at a southwestern copper mine more than two hundred million tons of over- burden have been removed prior to exposing an ore which contains less than 1% copper. A recent survey of twenty-three Western Hemisphere copper mines reveals the average strippingratio was 2.2:l with a range of 0.9-8.5:l. In the face of increased mineral demand, the resulting technological developments and rising overburden to ore ratios, many open-pit mines now use totally different concepts for the removal of ore and overburden. An increasing number of these concepts now being installed include wheel tractor scrapers as a major part of the material handling system for unconsolidated overburden removal. To say scrapers move only unconsolidated overburden is incorrect. On the contrary, ripped phosphate rock, copper ore, iron ore, and moderately consolidated overburden are also being moved by scrapers in various areas of the world. As reported in the Minerals Year- book, however, about one-half of the material moved in metal and non-metal mines is never drilled and blasted or broken by other means. We will, therefore, in this paper, concentrate on the role of wheel tractor scrapers in unconsolidated overburden; the area of greatest usage.

Jan 1, 1969

Jan 1, 1998

By Bo R. Arvidson

High-energy product permanent-magnet materials of rare-earth cobalt alloys are being used in applications where space or weight are at a premium cost. New applications like friction-free bearings are also made possible. However, such magnet materials have not been commercially used in magnetic separators until now due to the high cost for the overall magnetic flux generation relative to commonly used ceramic magnets or AlNiCo magnets. The design of the new high-intensity permanent- magnet roll separator (PERMROLL) takes advantage of the unique properties of rare-earth cobalt magnets rather than just substituting for conventional magnet materials now in use for magnetic separators. Hence, the new generation of high-intensity magnetic-roll separators has some unusual characteristics that make known magnetic separation applications more economically attractive, and even expands the magnetic separation technology area to include applications for which no other feasible methods are presently known.

Jan 1, 1983

By Kenneth P. Neumann

The development of the Cyprus Thompson Creek Molybdenum Deposit near Challis, Idaho, began in 1967 when the first mining claims were staked on the intrusive rock outcrop. Exploration drilling continued for the next 14 years. During 1978, a decision was made to develop the deposit. In December, 1980, approval of the Environmental Impact Statement was received and construction of facilities and waste rock removal began. By the middle of 1983, 126 M metric tons of rock had been removed and all facilities were completed. The high work ethic of Cyprus Thompson Creek employees combined with innovation has made the mine one of the most efficient in the United States today.

Jan 1, 1983

By Gilbert C. Robinson

Manufacturers of brick and tile are showing growing interest in the possibility of manufacture of a clay bonded block. The block would have the shape of concrete block, but would be made without the use of Portland cement, Instead, the block would be made' from mixtures' of an aggregate and the present raw materials of the brick industry. The finished units would weigh 20 to 30 pounds and meet the specifications for Grade A concrete block. The present status of the clay block development shows one manufacturer actually in production of these units$, two additional manufacturers are attempting production and many manufacturers are actively engaged in development work. At least four major research laboratories are engaged in the development program. There are several different processes available for clay block production. These processes differ primarily in the type of aggregate used or in the type of forming operation selected. I would like summarize these possible methods.

Jan 1, 1960

By Steven M. Bishoff

The reclamation of surface land areas disturbed during the course of coal recovery became a major, universal consideration upon the implementation of the Surface Mining Control and Reclamation Act of 1977. This legislation not only established reclamation as an absolute requirement, but also presented guidelines for reclamation standards and required bond-posting procedures to assure completion of the reclamation process. The Office of Surface Mining was established to enforce the provisions of the Congressional mandate by promulgating specifically detailed regulations and supervising the State participation in this regulatory process. The major operational consequences of the reclamation-related provisions of the Act and the OSM regulations are the increased costs and complex procedures necessary to accommodate the regulatory authorities. It is anticipated that many of these costs and procedures have not been adequately evaluated by either the coal operators or the regulatory bodies. It is, therefore, necessary to proceed with an examination of the general reclamation processes, the effect of these processes on product costs, and the methods, if any, which may be utilized to minimize their impact on the overall operation.

Jan 1, 1981

By Harvey P. Knudsen

This paper describes the results of a comparative study of the geostatistical ore reserve estimation method over three conventional methods; the polygon method, the inverse of the distance squared (IDS) method, and ELIP which is similar to IDS. Each method was evaluated on its ability to accurately predict individual block grades for one bench of the Pima Nine, located near Tucson, Arizona. Results at the Pima Mine indicate that the geostatistical method is no better nor worse in predicting block grades and total tonnage than the ELIP or IDS methods in contrast, the polygon method is clearly inferior. All of the methods would have given better results if geology had been included in the block model. At already producing mines ELlP or IDS may be good choices since they involve substantially less cost in computer time. For prospective or new properties, the geostatistical model is more attractive, due to its ability to construct confidence limits on the estimates.

Jan 1, 1976

By F. Soumis

We propose an advanced truck dispatching system which uses mathematical optimization approaches including integer programming, non-linear networks and the assignment problem. The system produces better operation control than existing algorithms. Furthermore, it provides planning tools for choosing equipment and finding an equilibrium between the quality and quantity of production.

Jan 1, 1986

By W. M. Middleton

The exploiting of geothermal steam is a new endeavor in this country and is for that matter a very new science in the world. With the majority of steam wells in the world having been drilled during the last twelve years relatively little experience and knowledge has been gained that can guide us as compared to the techniques the oil and gas producers have developed for their use. We few technical personnel associated with the field find it a continuous challenge to understand and explain what effects or causes the various unusual phenomenon experienced. We have had unending discussions attempting to formulate pet theories which we can use as guides. We know, so the geologists tell us, that the source of the heat is from the hot magmatic core of the earth. Theory has it that the magma is cooling off and that hot gases are given off as this magma cools and shrinks. In volcanic' areas along fault lines where the magma reaches closer to the surface than in other areas, there is a higher concentration of gas evolution; consequently, geyser or geothermal areas are developed. As these hot gases rise toward the surface they encounter various minerals, including overlying bodies of water. It is into these underground lakes that our wells are penetrating. As the heat enters these lakes it spreads out by conduction, convection and water migration. We can strike this hot water over quite large areas in many of the geothermal fields. At present there is one anomaly to this in the United States as there is in Italy where our wells do not penetrate a hot water lake. This is at The Big Geysers in California. Here superheated steam is produced with a heat content, so high that it could not have been boiled off of a fresh water pool. This puzzled us until last year when a well was completed into a large body of brine in the Imperial Valley. This brine exists at close to 500°F and at a hydrostatic pressure sufficient to preclude any boiling. It is now believed by some of us that a similar pool of brine must exist below The Big Geysers area, from which the steam is emanating. If there is such a brine pool, it offers a plausible explanation of the high-heat content, for brine boils at a higher temperature than fresh water. I am now beginning to think that a similar brine pool may exist under all the geothermal basins for if it is under two of them, it is highly probable that it is under the others. The partial understanding of what we are drilling toward, and formulating a theory to explain its behavior helps guide us in our steam well drilling.

Jan 1, 1963