Search Documents

"The paper treats the spatial aspect of mine sequence optimization. This aspect is revealed in the context of determination of the optimum number of cutbacks of an open pit mine. Cutback mining is a dominating method currently in base\precious metal mining and it is based on a pseudo-economic discretization of the pit space by using advanced pit design algorithms. The result of the implementation of such approach of pit design is the generation of pit shells, which need to be grouped into an optimum number of cutbacks for maximization of the project value. A mathematical solution of this problem is developed with the utilization of a combinatorial analysis. The solution provides a multi-variant investigation of the optimum mine sequence with the implementation of an author’s method for production scheduling optimization, which uses the Net Present Value as a criterion for assessing the economic efficiency of mine sequencing. A case study is provided for the conditions of a hypothetical open pit gold mine to illustrate the applicability of the approach. The results obtained reveal the complex nature of the variation of the Net Present Value as a function of the cutback geometry. INTRODUCTION The mine sequence optimization in open pit mining is a procedure that predetermines the efficiency of the production scheduling optimization. From a technological standpoint, the mine sequence optimization deals with two aspects – spatial and time. Each of them plays a tremendously important role in searching for the optimum solution of the open pit design problem. Original results on the time aspect of mine sequence optimization are published by Halatchev [2002]. They reveal a wide range of the Net Present Value (NPV) variation for a multi-variant arrangement of mine sequence over time and using a fixed geometry of the cutbacks, which determines the economic potential of a single open pit mine from a deterministic standpoint. The results show a range of NPV variation up to 30% depending on the stripping ratio of the mine. The effect of this variation is mainly due to the implementation of the mine planning principle of waste deferment in the scheduling optimization and using all theoretically possible variants of mine sequence arrangement by the inclusion of the bench sequences over the Life-Of-Mine (LOM) in the production process."

Jan 1, 2015

By Nico Sutmoller, Rich Palladino

Underground voids present a unique geotechnical engineering challenge. This paper will address materials and transportation mediums that are typically used for backfilling underground voids with native material. After reviewing traditional backfill and transportation methods, this paper will explore the advancing technology of foam transportation and the advantages of using this technology for transporting fill materials into underground voids to backfill them with Liquid-Sand. The paper will also review the benefits that Liquid-Sand brings to these applications and highlight specific case studies in which foam transportation has proven effective and provided cost-effective, environmental benefits.

Feb 1, 2025

By John E. Kinnison

The Mission mine, located in southern Arizona near Tucson, is a recently developed open pit which produces 15,000 tons per day of copper ore. The mine lies on a wide and gently sloping bajada sweeping northeasterly from the Sierrita mountains. It derives its name from the nearby Mission San Xavier del Bac, built circa 1700. The ore body is everywhere covered by about 200 feet of alluvium, as are the adjacent Pima and Palo Verde mines. The geology of the Mission deposit is known principally through the study of diamond drill holes spaced 150 to 300 feet apart. The open pit is in an infant stage and has not yet revealed much of the deposit, although information obtained there by the operating staff, and from a few thousand feet of exploratory underground workings, has added significantly to the general fund of knowledge. Permission to publish was granted by the American Smelting and Refining Company. I am indebted to Kenyon Richard and J. H. Courtright for criticism of this paper and for their direction during the several years in which I studied the Mission deposit. Acknowledgment is given to consultant in petrography, Robert L. DuBois of the University of Arizona. The only previous publication pertaining directly to the geology of file Mission deposit appeared in 1959 (Richard and Courtright), and may not be everywhere readily available. Cooper (1960) has published a short paper on the district

Jan 1, 1963

By D. Bhattacharyya

The adsorption and desorption of gold cyanide by activated carbon is significantly influenced by particle size of the activated carbon particles and the chemical environment. A series of adsorption and elution experiments have been performed with ten different particle size fractions. The tests indicate that although the ultimate adsorption capacity is independent of the activated carbon particle size, the adsorption rate is strongly affected by the particle size. Further, desorption characteristics using traditional Mintek and atmospheric Zadra procedures reveal interesting trends with variation in particle size and will be discussed in this paper.

Feb 23, 2014

By Robert D. Thomson

Land use is the single most important element affecting the quality of our physical environment. .The minerals industry is a user of land and by its very nature, directly affects the landscape. Mining is a very visible activity. Producers of sand and gravel, crushed stone, clay, cement and lime operate right at the interface of the public. These production sites must be located near population centers. People are more travel oriented than years ago and through use of the expanded interstate highway system visit remote and little-visited areas. They visit communities on their vacations, places they enjoy on weekends and places they drive past on business trips. Although not residents of these localities, they have a strong interest in changes that occur in the landscape. As a result, the public has a greater concern today about mining and its use of land. From 1930 through 1971, the minerals industry used 3.65 million acres, or 0.16 percent of the land mass in the United States (4)2/. Of the total 3.65 million acres utilized, about 59 percent was accounted for by the area of excavation, 20 percent by disposal of overburden and other mine wastes from surface mining, 13 percent by disposal of mill or processing wastes, and 5 percent by disposal of underground mine wastes; the remaining 3 percent was subsided or disturbed as a result of underground workings. Nonmetallic minerals and fossil fuels each accounted for 43 percent of surface land used during 1930-71; the metal mining industry utilized the remaining 14 percent.

Jan 1, 1976

By Robert Stefanko

The most perplexing problem that has confronted mining engineers since the dawn of mining has been strata control. For the purposes of this paper, strata control will be defined as control of ground in the immediate area surrounding the, mine opening. To prevent movement of the surrounding strata into underground mine openings, miners have traditionally relied upon some type of artificial supports placed within the openings and located in a manner determined by trial and error from previous experience. Without the means to measure changes of stress in the supports and within the mine structure itself, an evaluation of the efficiency of the supports and mining system was impossible. Strata control thus remained an art with very little application of science. During recent years a revolution has occurred in mining. The modern mining engineer is contented no longer-with trial and error methods but is utilizing all the technological information at his command to obtain a solution to this age old problem. However, serious problems have arisen due to the lack of certain basic knowledge in three important areas: 1, The original stress distribution within the earth strata prior to mining. 2, Redistribution and concentration of the original stresses with mining activity. 3. The properties of rock that are significant in failure and its prevention.

Jan 1, 1960

By Daniel A. Payne

For many years underground mining in the Sydney Coalfield has suffered from the effects of high horizontal stresses. It is only in the last 15 years that they have come to be recognized, understood, predicted and even avoided. This paper relates experiences in three coal mines in three different seams in the Sydney Coalfield. The effect of the direction of the principal horizontal stress on the direction of drivage of gate roads, access roadways and longwalls is described. Results of a monitoring program to measure the change of magnitude and direction of the principal horizontal stress in the gate roads as a result of longwall mining are also presented as well as the effect of the direction of principal horizontal stress on the shape of sandstone/gas outburst cavities.

Jan 1, 1998

By N. O. Lotter

Studies investigating the evaluation errors in laboratory scale flotation tests for platinum-bearing Merensky Reef in the Bushveld Complex, South Africa, have constructed a quality control model to assure a 95% confidence in the attested data. Specialized knowledge of the mineralogy of the platinum-group elements (PGE), together with acquaintance of evaluation models, validate a systematic checking of the sub-processes of the testwork. These include determination of minimum mill feed sample size, assay head reference distribution, mass balance checks, and specialized sample preparation of flotation test products prior to analysis. A flow schematic of this quality control model is proposed, with an example of test data that produce an error in the metal balance of 0,2% after rejection of outlier data.

Jan 1, 1995

By James N. Orlich

Meridian Gold Company's Royal Mt. King mine (RMK), a subsidiary of FMC Gold Company, is located approximately 40 miles east of Stockton, California on the western edge of the historic mother lode belt. Gold ore at RMK is associated with a series of northwest trending fault zones hosted in either meta-volcanic or meta-sedimentary rock types commonly referred to as greenstone sulfide and carbonaceous phyllite. Mineralogy studies show gold in both ore types to occur primarily as electrum in the form of 1 -20 um inclusions in pyrite with varying amounts of free milling gold. In carbonaceous ores, gold was not found to be closely associated with carbon. At the start of the current mining operation, three major ore resources were identified. North Pit and Gold Knoll pits were the major greenstone reserves while Skyrocket Pit contained over 60% of the total reserves as carbonaceous ore. Since North Pit and Gold Knoll were to be the first areas mined, the mill began operation in February 1989 with a flowsheet designed for greenstone ores with a carbonaceous expansion anticipated after depletion of the greenstone reserves.

Jan 1, 1992

By Harold F. Yde

Hydraulic tailings fill in the Butte deep level mines was based upon studies made in 1958 by the Anaconda Company Mining Research Department, which published Bulletin No. 35, entitled "Hydraulic Stope Filling". Since then, many things have changed. At the time of the Research Departments study, dry mine tailings were hauled by rail cars from the Anaconda tailings ponds, twenty-five miles distant, to the underground mines' tailings fill plants at the Leonard Anselmo, and Mt. Con Mines. Now, with the installation of the new Weed Concentrator in Butte, tailings is delivered by pipeline to a cyclone at the Kelley Shaft, and stope filling has become more highly automated and streamlined. Presently, mill tailings at approximately thirty percent solids by weight, is pumped from the concentrator, eight thousand feet horizontally and upward, to the Kelley Fill Plant, where they are dewatered and deslimed by three Krebs Model D20B Cyclones, which discharge the material into the cased and grouted mine delivery bore holes at desired densities up to seventy percent solids. The vertical boreholes and four-inch rubber lined Victaulic pipe carry the material downward to horizontal distribution lines, which in turn tap into the stops-filling, three inch, unlined steel Victaulic pipelines. The slurry may travel several thousand feet before it finally discharges into the stope, where it lends support to the mined-out area.

Jan 1, 1969

By L. E. Mercando

The proposed Flambeau Mining Project is based on a high grade copper deposit located approximately one mile southwest of Ladysmith, Wisconsin. The project involves only the mining, crushing, and shipping of ore to facilities outside of Wisconsin for processing. The Wisconsin environmental regulations include provisions for identifying wetlands, the requirements for minimizing the disturbance of wetlands, and the need to establish new wet-lands to replace any wetlands which have to be disturbed.

Jan 1, 1991

By J. E. Lowe

The unique application of a large walking dragline in the mountains of southern West Virginia was developed and implemented by Hobet Mining, Inc. Hobet is an independent operating subsidiary of Ashland Coal and is headquartered at the No. 21 Mine in Boone County, West Virginia, near Danville. Hobet also operates the 07 Mine located in Logan County, West Virginia, near Holden. Both mines are similar in equipment and manpower used; both produce over 2,000,000 tons of clean coal annually. Each site encompasses large, contiguous properties with access to rail service. The larger of the two is the Boone County property; it totals nearly 40,000 acres and has ample reserves. In 1977, Hobet was in the process of constructing a preparation plant (Beth Station) at its 21 Mine site with a capacity for two million tons. One of the first orders of business was to design a mine plan that would provide production for the capacity of the plant. Coal production would come from a more than adequate reserve base using the most economical mining methods available. Hobet looked at different deep and surface mining methods to use in order to develop the property; ultimately, it was determined that the mountaintop removal method with the use of a large dragline was the most economical way to develop reserve. Prior to this time surface mining in mountainous Southern West Virginia was generally done by contour mining and/or augering techniques.

Jan 1, 1993

By Jr. Zink

An economic and operational evaluation of the unrecovered metal, physical conditions, and chemical environment in a leach pad should be made prior to decommissioning. This evaluation will help determine the possibility and method of secondary and/or enhanced metal recovery and the method(s) to be used for detoxification and heap closure. The evaluation requires quantitative sample collection in a locally variable, yet grossly homogenous material. An assessment of a valley fill heap leach pad was made using a technique borrowed from placer technology called sonic drilling. The sonic drilling technique produced very satisfactory core recovery and sample quality. At this site, drilling results demonstrated that the method of heap construction produced expected features after extensive long term leaching. Rather than a uniformly homogenous pile of metallurgically depleted crushed ore, an assemblage of solution channels, un-oxidized sections, unleached areas, and compaction due to various factors, were found. These conditions are thought to represent a normal, rather than unique, situation for a valley fill heap leach. The lack of this information can have a significant impact on the economics and methods of heap re-handling and ultimate closure.

Jan 1, 1992

By H. C. Rolseth

The first step in the quarrying of granite, following removal of any overburden material, involves the freeing of large blocks from the formation. For many years the use of explosives was the accepted method of obtaining these blocks. Even today there are operations where this is considered to be the most economical method even though it does result in a high percentage of damaged stone. In more recent times the preferred procedure at most quarries has been to produce a continuous vertical cut or slot completely around the block to be separated. Originally, this was done by drilling a series of closely spaced holes around the block and breaking the web between the holes with a chisel-like tool known as a broaching bar. The machine used in this mechanical method of producing the relief slot is known as the channel bar. The modern day approach to the production of continuous channels was introduced to the industry around 1955 by the Linde Division of Union Carbide Corporation. The method employs a small rocket - jet burner producing a high temperature, high velocity exhaust flame which when directed against the granite causes it to disintegrate. This method, which has come to be known as "Jet Channeling", is now used by practically every major granite producer in the United States and Canada.

Jan 1, 1968

By C. Patrick

Longwall face-to-face transfers can cost over $100 per minute in lost production potential and $100,000 for personnel and supplies. Such high cost makes extensive planning and control of the transfer process a critical necessity for the economic feasibility of longwall operations. This paper reports operations research techniques used for the analysis and modeling of longwall face-to-face transfers. Transfer data has been collected from companies who operate over 30% of the total U.S. longwall faces. Comprehensive sequence networks of existing longwall transfers were developed; simulation models of transfers under varying conditions were generated; and, the economics of general transfers and time-cost tradeoffs in the transfer procedure were investigated.

Jan 1, 1993

By E. J. Karges

The use of pulverized coal for generating power and performing industrial processes has made an important contribution to our industrial economy during the past half century. Actually, the burning of coal in powdered form is a subject that has held the attention of engineers for a century or longer. Its widespread use, however, is comparatively recent, As early as 1866 patents were granted to Messrs. Whelpley and Storer for a method of feeding pulverized coal into a furnace as an auxiliary to the grate fuel. In the many tests made during the subsequent years with various kinds of apparatus, the experimenters were handicapped in not getting the coal fine enough to obtain complete combustion and to prevent excessive formation of slag.

Jan 1, 1965

By R. L. Bullock

The New Lead Belt of Missouri, situated in the heart of the Clark National Forest, stands as a dynamic example of how mining activities can successfully coexist in a restricted wilderness area. After 16 years of intensive drilling activity, mine development and surface plant construction, many would agree that the mine-plant design philosophy of St. Joe has minimized the imbalancing effects to the ecology and the wilderness appearance of the Ozark area. In a recent dedication speech of St. Joe's newest operation, it was stated: 1 "this Brushy Creek Mine, as well as nearly all of the mines in this district, lies within the boundaries of the Clark National Forest. Here the Forest Service has an outstanding and realistic program for multi-use of Federal lands. Mining, lumbering, recreation and conservation coexist in, what I consider, a delightful wilderness environment. I believe that this same type of usage could be permitted on all government land without seriously detracting from its natural beauty." Each and every activity in the process of discovery, exploration, development and finally operating a mine and process mill could have drastically degraded some phase of nature's environment were it not for the well developed and executed plans of the mining people involved. This is not to say that everything has been kept in perfect balance; but most certainly the industrial impact on what was once a wilderness area has been held to a minimum. What follows is the story of how each phase of this gigantic development was handed by industry people. Through their interaction and cooperation with government agencies, educators and researchers, allowed not only the ecology of the area to be protected, but the aesthetic beauty of the Ozarks to remain intact.

Jan 1, 1973

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 D. R. Hembree

This paper discusses the mineralogy and metallurgy of the Kuroko-style volcanogenic massive sulfide ores mined at Formosa Exploration Inc. I s Silver Butte Mine located in southwest Oregon. The principle ore type is pyrite + chalcopyrite + sphalerite, while subsidiary pyrite + bornite + sphalerite ore is also mined. The two styles of mineralization have distinctly different metallurgical behaviors and must be treated separately. Selective flotation methods are used to produce copper and zinc concentrates from the first ore type, while bulk concentrates are produced from the bornite ore. Careful mine planning and coordination between the mine and mill are utilized to achieve optimal recoveries.

Jan 1, 1993

By Ernest B. Snyder

The word "line" has been used loosely for many forms of the common steel plant flux. For example, many people use the word "lime" for nigh calcium and dolomitic limestone, for high calcium and dolomitic quicklime (also called caustic lime, calcined lime; burnt lime, pulverized and pebble lime) and ;van for clinkered dolomite. Calcium hydroxide, also called slaked lime and hydrated lime, is called "lime" but is seldom used as a flux except when the quicklime air slakes in open boxes or bins. All of the above forms of "lime" are used in the steel plant. Calcium hydroxide is used for water treatment, acid neutralizing, and as a lubricant for wire drawing. All the other limes are used as fluxes in the sintering plant, blast furnace or steel producing furnaces. In the production of self-flux or super-flux sinter, high calcium and dolomitic limestone fines are used. Where quicklime fines are available, they may be added to the sinter mix also. The blast furnace uses both high calcium and/or dolomitic limestone. A few trials have been made using iron oxide stabilized dolomitic lime in an attempt to reduce coke consumption and to increase the production rate. The trials were very successful but would' not be economical, except in periods of coke shortages, with resulting extremely high coke cost and exceptionally high hot metal demand.

Jan 1, 1979