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By Ken J. Richards

Industries dependent on pyrometallurgical processing generally find themselves facing a common set of problems, namely, serious environmental restrictions, heavy capital requirements for new facilities and for plant modernization, the certainty of rapidly escalating fuel costs, and the uncertainty of fuel availability. To remain competitive, it has become clear to industry that a new dimension of attention must be given to assuring the maximum performance from plant facilities already in place and from those that are built in the future. In the last decade or so, in response to these needs, there has been an acceleration in the development of new pyrometallurgical process concepts. Their application, though spotty, is increasing. A common factor in this developing base of technology is the need for effective process control. Digital control is an indispensable element of meeting the challenge. We cannot make the point, however, by looking to a general survey of instrumental control of pyrometallurgical processes. Computer control is in its awkward adolescence. Its application is so new that only isolated applications can highlight the trends. For this reason, the authors have chosen to focus on the nonferrous smelting industry to illustrate the status of pyrometallurgical processing and control. We believe this approach will best meet the interests of most readers of this edition and the background of the authors.

Jan 1, 1979

By W. S. Hannan

History Leaching of sulfide ore was first attempted by the Phelps Dodge Corporation about 1900 at Bisbee, Arizona, when Dr. James Douglas conducted experiments in an attempt to apply the leaching techniques then in use at Rio Tinto, Spain. Although this initital attempt was unsuccessful, research work was continued which culminated in successful leaching operations at Tyrone, New Mexico, in 1917 and at Bisbee beginning in 1920. Leaching has continued intermittently since that date, with material from the Lavender Pit being leached today. The Lavender Pit Leach Dump Stripping for the Lavender Pit was started in 1951, with mining operations on stream in 1954 and continuing to the present. All material removed from the pit has been classified as waste, leach material, milling ore, or direct smelting ore, depending upon grade and degree of oxidation. Lavender Pit leach material has been stockpiled in a single dump, called No. 7 Dump. This dump covers an area of approximately 135 acres and average about 300 feet in height. The dump has been deposited over a period of 20 years by truck haulage and contains several layers, each of which has a permeable boulder layer at the bottom and a compacted layer at the top. Leaching of Lavender Pit material was started in 1956 and has proceeded simultaneously with dump construction. Former leach pond areas and haulage surfaces have been ripped with D-9 tractors before deposition of succeeding layers of ore.

Jan 1, 1972

By H. H. Murray

Recently developed clay deposits that will impact regional and world markets are described. These deposits, their location, geology, and physical properties are delineated. Kaolins from the State of Para in Brazil and from Ukraine; bentonites from Argentina and India; and palygorskite and sepiolite from China are world class deposits that when processed using modem technology will produce excellent products. Other deposits that may affect regional markets are l<aolins from China, Australia and Indonesia; bentonites from Georgia (formerly USSR) and China; and palygorskite from India and Ukraine. New ball clay deposits that will affect regional markets are in China and Indonesia.

Jan 1, 1999

By John E. Tilton

Mining is one of the oldest human activities. It goes back at least to the Bronze Age and possibly even the Stone Age. The Romans mined copper in Spain and tin in England some two thousand years ago. The writings of Agricola in the 16th century show that mining was important in the Middle Ages. Today we mine more mineral commodities in greater tonnages than ever before. This long and fascinating history closely tied with the economic development of the human race is one of the charms of the mining industry. It also, unfortunately, gives rise to some widespread misconceptions.

Jan 1, 1997

By E. K. Albert

In 1977, Congress enacted Title IV of the Surface Mining Control and Reclamation Act (SMCRA), providing for an "abandoned ml.ne reclamation fund". This fund, taken from a fee collected from operating coal mines, provides capital for the reclamation process. However, given the number and extent of abandoned mine sites in some states, the question of project selection is important. This paper describes a project in progress to create a Management Information System application for project ranking under multiple objectives. The benefit of this project for the need of new environmental control technologies will be discussed.

Jan 1, 1990

By Greg Struble

The Homestake Gold Mine is one of the deepest and most extensively developed hardrock mines in North America. The mine is divided into five divisions which produce a total of 1.7 million metric tons of ore per year. In the past, labor intensive mining methods such as open cut-and-fill, shrinkage, and timber stoping were utilized. In recent years there has been an extensive change to the more productive methods including Vertical Crater Retreat and Mechanized Cut-and-Fill. Also, the percentage of production from the lower divisions below the 4850 level is increasing while upper level reserves are beginning to decline. Combined, these factors have strained the ventilation resources to the limit. By early 1984 it became clear that future production trends would require a detailed study of future ventilation resources. By November of 1984 the Ventilation Department completed a study to project these future requirements. This paper will detail the first phase of a scheduled two phase upgrade: the installation of a new surface fan.

Jan 1, 1987

By J. H. Rowland, A. C. Smith, K. A. Teacoach

Current regulations for fire suppression systems in underground coal mines to protect conveyor belt installations have been in place since the Coal Mine Health and Safety Act of 1969 was enacted. Over time, the coal conveyer equipment being used and ventilation conditions underground have changed significantly, particularly the width of the conveyor belts and the use of belt air at the face. The effect of these new conditions on the effectiveness of suppression systems during a fire is not known. The National Institute of Occupational Safety and Health (NIOSH) conducted a study to evaluate the effect of air velocity, water sprinkler activation temperature and a limited water application time on the effectiveness of water sprinkler fire suppression systems to extinguish large-scale conveyor belt fires. The fire tests were conducted using both new and used 1.8-m-wide, fire-resistant rubber belt that met the Mine Safety and Health Administration (MSHA) flame-resistant requirement specified in Title 30, Code of Federal Regulations, part 18, section 18.65 (also known as the 2G test). Tests were conducted using standard response sprinklers with activation temperatures of 68° C and 141° C at air velocities of 0.5 and 5.1 m/s. Two tests were conducted at both air velocities for each sprinkler activation temperature, one using a new belt and one with a used belt. The results showed that the suppression system was able to suppress the fires in ten minutes to the point that a miner could extinguish it with a fire hose. However, in several of the tests, the fire reestablished itself a few minutes after the sprinkler water supply was cut off and quickly grew out of control. This report discusses the large-scale experimental configuration, the installation specifications of the fire suppression system and the results and conclusions regarding the effect of air velocity, sprinkler activation temperature and limited water application on the suppression system performance.

Jan 1, 2010

By Roland W. Merwin

The Bureau of Mines has studied the possibility of using the heap leaching process for treating the gold ores in the sedimentary beds of northeastern Nevada. This paper summarizes all available information on the technical and economic feasibility of heap leaching oxidized ores from these beds, past industry application of vat leaching, results of recent Bureau of Mines and industry tests on heap leaching ores from this region, and requirements for planning the proper application of heap leaching. Preliminary tests on representative samples of ores from the region show that a satisfactory recovery of gold can be obtained by heap leaching the ores with cyanide at a relatively coarse size. Significant deposits of gold ore occur in sedimentary beds of various locations over an extended area 40 miles wide and 200 miles long in northeastern Nevada. The area is centered 40 miles west of and runs parallel to the leading edge of the Roberts Mountain thrust fault system, a prominent geologic feature in the area. The general locations of past and present gold mining operations are shown in figure 1. (slide 1)

Jan 1, 1969

By Claus Becker

In Europe, approx. 50 km of traffic tunnels are under construction using Slurry-or EPB Shields or Convertibles of all sizes, among them the biggest slurry shield ever built up to now with 14,20 m diameter. Main characteristics and special features of the machines will be explained relating to geology, cover and water pressure. This gives a comprehensive overview of the latest developments of this kind of machines.

Jan 1, 1999

By J. H. Meza Viveros

This paper describes some actual parameters and technologies used at Mexicana de Cobre Smelter, and the principal design parameters and new technologies which wiil be used with the smelter expansion project, in order to increase the production capacity of anode copper from 180 000 mtpy to 300 000 mtpy. Likewise its describe some parallel projects under construction also in the smelter plant.

Jan 1, 1997

Traction of mining vehicles is well understood for a variety of unfrozen road surfaces, allowing optimal design of mine access and haulage roads. However, no such characterizations exist for the frozen or partially frozen surfaces typically encountered in Northern regions. Recent work by U. S. Army researchers suggests methods for characterizing roadway traction for any vehicle on the basis of test measurements made with a standard test vehicle. Such a test vehicle was designed, and several sets of test data were recorded at the onset of winter in Fairbanks, Alaska. This work suggests methods for future research and possibilities for the use of such research in designing drive systems, tires, and mine roads for Arctic and sub-Arctic mines.

Jan 1, 1995

By X. X. Shao

Dewatering of ultra-fine clean coal slurry to a low moisture level of20 percent is difficult using the conventional techniques. A novel approach, which utilized mixing of fibrous waste material, such as paper, carpet and wood, with coal slurry prior to dewatering was developed. It was found that addition of about 10 Kg/t of carpet fibers or 5 Kg/t of raw paper pulp lowered the filter cake moisture from 22.5 to 18 percent. The compressive strength of the filter cake improved from 0 to 4.5 Kglcm2 and impact resistance from 0 to 4. The experimental data indicated that the handling character of the dewatered fine coal was improved significantly.

Jan 1, 1998

By John M. Gullbert

It is the task of this portion of today&apos;s session on the new meaning of regional tectonics in the search for ore districts to discuss known interactions of tectonics and ore deposition in the &apos;new global tectonics&apos; context. I will speak particularly about known applications of the recent tectonic advances to ore finding. Stated yet another way, it&apos;s getting on in time toward the "put up or shut up" stage-¬and I would not be here if I thought that the new tectonics were not an effective present matrix for ore finding. Before delving into specific geologic relationships--and I propose to discuss mainly the evolution of an idea which may reveal the presence of a major copper deposit on mainland Mexico--I must note that there have been no published accounts that I know of which assert that a particular discovery has been made soley and specifically because of an interpretation based upon mechanisms directly linked to sea floor spreading or plate tectonics. It is nonetheless true" that several major exploration efforts are based upon such interpretations, and, as is normal when exploration ideas are involved, one does not wish to call attention to an advantageous position in a highly competitive business. Little might be expected to have been announced in so fast-moving and potentially lucrative an area. Another point which needs to be made is that people such as B. S. Butler (1933), Billingsley and Locke (1935 and 1941), Harrison Schmitt (1935), and more recently Mayo (1958) have been working for decades with the tectonic expressions of the emergent tectonics without recog¬nition of the driving forces or the unifying tectonic concepts

Jan 1, 1971

By F. M. Benavides

This paper presents recent developments in federal environmental regulations, which in the view of the author, affect mining and the mineral processing industries. This is a summary of activities by the administration, congress and regulatory agencies during 1990. The information presented is a recap from material published. The emphasis is given to Air Quality regulations, although other environmental concerns are reviewed.

Jan 1, 1991

By Glenn E. Craig

The practical and effective pulp distributor here presented is believed to be of a completely new and innovative design. It was developed at the San Nicolas Plant of the Marcona Mining Company in Peru, where it has been thoroughly plant tested using iron ore slurries of a particularly abrasive nature. It has proven to be superior to the apparatus originally installed, or to any observed in operation elsewhere. In plant practice the capacity and efficiency of many process units such as screens, magnetic separators, and jigs are strongly affected by the loading pattern, and for better results the flow of pulp must be proportioned across the receiving lip in equal quantities per unit width. The distributors originally installed on the drum magnetic separators in San Nicolas proved to be unsatisfactory, and several trial modifications failed to show any improvement. As is usually the case, feed rates were being steadily increased, and appreciable losses to tailings resulted. A check of the distributors on the market discloses no reasonable substitute, so efforts were directed toward devising an entirely new type. Required was a positive type of action which would guarantee that the pulp flow be spread equally along the length of the drum. Discussion As indicated, the motivation for development was simple necessity. The plant in San Nicolas crushes, grinds, and concentrates magnetic iron ores of a particularly abrasive nature, and depends largely on magnetic separation to obtain a marketable product. Feed to the numerous drum magnetic cobbers and finishers varies from rod mill discharge at a nominal minus ten mesh to a ball mill fine grind of seventy percent minus three hundred and twenty-five mesh. Operational factors affecting the magnetic separators were well controlled,

Jan 1, 1971

By F. Grajales Munoz

The Cienega project, now under construction by Penoles group, is located in the mountains of the State of Durango, Mexico. The gold and silver deposits are found in the 4-km long system of veins, which will be extracted by underground methods. The planned 1000 tpd process plant will contain a countercurrent cyanide circuit for oxide ore and a flotation circuit for sulfide ore. Considerable resources have been devoted to development of infrastructure in the isolated location, as well as for the mitigation of environmental impacts. Startup is scheduled for the third quarter of 1994.

Jan 1, 1994

By Rudolph H. Jacobson

The leaching of heaps or sub-marginal waste ore dumps as it is practiced throughout the Southwest as well as other parts of the world, is the major method of secondary recovery of copper. In 1970, twenty percent of all domestic copper was produced by dump leaching operations (l). In recent years, this method has been successfully extended on a limited scale, for the recovery of uranium from low-grade ores (2). It is inevitable that this technique will be increasingly employed in metal production to satisfy the insatiable demand of our mineral based society. Although dump and heap leaching has been used effectively for some time (3) , its application has been more of an art than a science. Therefore, it is essential that we learn about the important factors and parameters affecting this versatile process so that we may make increasing use of this technique in the future. The dump or heap leaching process encompasses the preparation of ore for-subsequent inplace leaching, the flow of solutions and ionic species through porous rock masses, the leaching of minerals with inexpensive and, if possible, regenerable lixiviants under prevailing conditions of the inplace environment, and the recovery of metals from the pregnant liquors. It is evident that this comprehensive scope of dump or heap leaching falls under the realm of interdisciplinary science and engineering requiring the application of the principles of physics, mineral engineering, hydrology, computer modeling, operations research, economics, and allied disciplines. An exhaustive study of the phenomenology of a leach dump or heap requires detailed knowledge of the simultaneous interaction of&apos;

Jan 1, 1972

By Harry H. Peek

Artesian pressures of unusual magnitude occur in the deeper aquifer units beneath a considerable part of southeastern North Carolina and extend into South Carolina. The high pressures were first observed in 1968 in wells near Wilmington that were drilled to "basement" rock and which were screened between depths of about 260 to 300 m (meters). The pressure was recognized by Peek and Heath1 as an anomalous geo-pressure and unrelated to recharge conditions in the region. Since 1973, much new information has been obtained on hydro-geologic conditions in the area and a preliminary report on the deep artesian pressures was published in 1975.2 Most of the basic information has been obtained from groundwater research stations constructed by the Groundwater Section of the North Carolina Department of Natural and Economic Resources as a part of Ground-water studies in the Coastal Plain Region. These stations consist of an exploratory well drilled to basement rock with wells completed in each principal aquifer unit to provide data on aquifer characterestics, water levels and water quality.

Jan 1, 1977

By R. O. Y. Breese

Perlite is a hydrated acid volcanic glass that has been derived from the alteration of obsidians through incorporation of water into the silica structure. It is distinguished from other members of the water-bearing natural glass family by total water content, characteristic fracture and luster. The distribution of major occurrences worldwide is associated with silicic Tertiary through early-mid Quaternary volcanics related to plate movement. The No Agua dome and flow complex is one of the most highly studied perlite occurrences in the world. It clearly exhibits lithologic and textural zonations that reflect simple cooling history. Similar features are commonly observed within other perlitized, extrusive glass selvages. This paper briefly discusses current thought regarding geologic occurrence, the hydration process and the modes of origin with special emphasis on No Agua.

Jan 1, 1985

By George M. Meisel

This paper is devoted to a discussion of the factors governing design of concentrators for large grinding circuits. Emphasis is placed on the manner in which use of ever larger grinding mills has affected the size of grinding bays, service cranes, gear reducers and electric motors, and the selection of ancillary equipment for cushioning of the starting load of large mills. Information is presented on the effect of using large grinding mills on the capital and operating costs of concentrators, e. g. : (Fig. 1) ? Benefits in lower cost of mills, drives and materials handling equipment, plant space, power, grinding media, operating labor and maintenance, and in ease of instrumentation and automation. ? Penalties in distribution of materials from the grinding mills to multiple lines of equipment which have not been developed to commensurately large sizes, and higher cost of ancillary equipment.

Jan 1, 1968