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By Glenn J. Phillips, Debra L. Musick

The operating mine is dynamic, everchanging, and a continuous moving target. The only way to effectively manage such a creature is to be able to evaluate the cost of operation over short enough time periods that rapid effective controls can be implemented before loss can erode the marginal profits in todays market place. Such short term evaluations can provide the basis for the long range planning that can keep an operation healthy in the future. The spreadsheet programs on small computers (PC's) offer the possibility of such evaluation by accumulating data in a useable format, providing timely cost reporting and providing a tool for use in evaluating the day to day alternative choices of the real mining world.

Jan 1, 1987

By D. Marino

Over the last 20 years, the manufacturing sector of our country has been called upon to comply with ever core stringent environmental standards. The primary metals sector was particularly hard hit early on, to develop the technology, acquire the equipment, and implement the programs to eliminate or reduce the by-products of metal making. To this end, through a combination of technological innovation and extensive capital expenditures, the metals industry has met, and in many cases, exceeded the minimum standards. It is to this escalating cost - liability exposure issue - that Dereco has addressed itself. As we move into the decade of the 90's, the challenge facing the metals industry concerning the environment will be even more difficult than the previous decade. To focus in on one major aspect of legislated environmental regulations, the issue we will address today is; now that the by-products of metal production have been identified, accounted for and collected, how are they to be disposed of? During the course of this presentation, actual data will be presented from our 4 1/4 year on-site experience at J & L Specialty Products

Jan 1, 1992

By Vijenac Quarry, A. Iljazagic, t. Knezicek, T. Omeragic

Limestone quarry Vijenac, is one of the key limestone producers in B&H. Conventional massive drilling and blasting is the technique applied for limestone exploitation. Utilized blasting scheme causes appearance of large oversize stone pieces, uncontrolled flying stone and undesirable seismic effects. In order to reduce or eliminate exposed disadvantages and to improve environment in the area of Vijenac quarry, an innovative blasting scheme was tested. Conventional blasting scheme was changed from single row, deep inclined blast holes combined with two lines short horizontal holes to multi row, inclined blast holes combined with a single line short horizontal blastholes. Applied innovative blasting scheme reduces negative blasting impact on the environment through safer working conditions, reduced amount of dust after blasting, reduced explosive and energy consumption, reduced appearance of explosive gasses and reduced earth and air vibrations as the result of seismic effects.

Jan 1, 2005

By Luc Morin

What you don't know won't hurt you! This attitude can get you into trouble when considering your process! When trying to extract the most and the best possible performance from a mineral processing circuit this should be reworded to say: What you don't know about your process will hurt your profits! Today, with the popularity of joint ventures, custom milling contracts and process audits by specialists, not knowing is a formula for trouble! Good Sampling Systems are no longer considered a luxury' Not too long ago the practice of grab sampling was considered acceptable and became the norm. Today, it is rare to hear metallurgists say, "All I need is a trend not a good representative sample. so I'll just grab a sample every few hours." Buyers and sellers of quality products have found that grab sampling leads to poor partnerships'

Jan 1, 1999

By Douglas B. Silver

Study Parameters (Status as of February 1993) Time Period: 1989 -1991 151 North American Public Metal Mining Companies Fiscal not calendar year basis 85+% of Canadian and U.S. Metal Production Au, Ag, Cu, Pb, Zn, Mo, Ni, W Results are Preliminary and Research Continues Chicken Little is Alive and Well

Jan 1, 1993

By Fumio Wada

Kuroko deposit is a stratabound massive sulphide and sulphate deposit associated with Miocene submarine volcanics and has been considered to be a prototype of meta- morphosed Palaeozoic and Precambrian equivalents. Since the discovery of Uchinotai deposit of the Kosaka mine in 1959, Dowa and other mining companies have conducted intensive exploration work in the Hokuroku district of northeastern Japan. Dowa has been placing its first priority on the exploration of Kuroko deposits and made a series of remarkable successes in finding the Kuroko deposits, i.e. Uchinotai, 1959; Matsumine, 1963; Uwamiki, 1966; Fukazawa, 1969 and Ezuri, 1975. It is emphasized that our successes have resulted from the proper application of exploration technologies accumulated through our experiences. Firstly we defined the Kuroko horizon and favourable felsic volcanism based on the detailed structural and volczno-stratigraphic study of the Hokuroku district, and then delineated the promising areas by means of the quantitative evaluation of geophysical, geochemical and mineralogical parameters such as the magnetic susceptibility and contents of alkaline and alkaline earth metals in the foot wall dacites and clay mineral assemblages of both hanging and foot wall pyroclastics and dacites. Practical application of these techniques is essential to our routine Kuroko exploration.

Jan 1, 1982

By James M. Link

The first rule of mineral deposits always seems to be: the deposit is never close to the market. With gems and precious metals, this is not much of a problem. But with most of the mineral commodities used in today's world, transportation becomes a major part of the cost to the consumer. In Japan, for example, more than 60% of the cost of coal to the consumer may be attributed to transportation. The purpose of this article is to examine pipeline transportation, particularly mineral slurry pipelines, as a means of getting the mineral to market. Pipelines Today Regulated pipelines in the US totaled nearly 724 Mm (450,000 miles) in 1980 according to the Federal Energy Regulatory Commission (FERC). Worldwide, more than 210 Mm (125,000 miles) of new pipelines will start construction in 1982 at an estimated cost of more than $150 billion. According to the Bechtel Corp., the period between 1982 and 2000 will see major growth in pipelines of all kinds. In North America, major movements of crude oil from Alaska and synfuels from the Rocky Mountains will require the construction of nearly 16 Mm (10,000 miles) of new pipelines. Nearly 42 Mm (26,000 miles) of new gas transmission pipelines will be needed to tap both US and Canadian arctic gas fields and move the gas to major markets on both coasts. Other pipelines will be required to move additional quantities of natural gas from the Rocky Mountains to more populous regions. Bechtel says more than 24 Mm (15,000 miles) of slurry pipelines will be needed to transport coal from both eastern and western coal provinces to the Mississippi valley and coastal areas. In 1980, 125 companies delivered more than 1 km3 (6.5 billion bbl) of crude oil and 652 hm3 (4.1 billion bl) of products in the US. At the same time natural gas pipelines transported 498 km3 (17.6 trillion cu ft). The reported investment by these companies was nearly $20 billion at the end of 1980. Advantages of Pipeline Transportation The obvious success and vitality of the oil and gas pipeline industry is based, at least in part, on the fact that pipelines are a very efficient and low-cost method of transportation. This fact, coupled with the need for lower cost trans¬portation, has led to the marriage of oil and gas transmission technology and the bulk mineral solids transportation industry. The off-spring of this marriage is the mineral slurry pipeline. Slurry pipelines have a number of advantages over other transportation methods. One of these is the fact that they are buried-out-of-sight, out-of-mind. Second, they are relatively small users of labor because they lend themselves to automation and remote, or even computer control. Third, they offer an attractive economic alternative to other transportation systems. For example, for a 1000 km (621 miles) distance, rail costs of 1?/ km (1.7?/ton-mile) are about equivalent to slurry pipeline costs. But, as the distance increases, pipeline cost per t-km continues to drop while equivalent rail charges remain essentially insensitive to distance. Where existing rail, barge, or ocean ships are available, the cost of new construction associated with a slurry pipeline probably will render it noncompetitive. However, where new rail or other construction is needed, the cost of a slurry pipeline is very competitive. About three-fourths of the cost of a pipeline is in pipe, fittings, and construction. Nearly a fifth of the investment is in pump stations and the remainder is in right-of-way, surface facilities, utility acquisition, communication facilities, and other support areas. The fact that pipelines are capital intensive is, at the present time, a mixed blessing. For example, the delivered cost of coal in a hypothetical project doubles when the cost of money rises from 9% to 17.5% per year. The largest cost element for delivered coal in this example is in depreciation and finance charges. The next largest cost element is electricity to power the pumps, with labor making up the smallest increment of the delivered cost of coal. World Slurry Pipelines The idea of a slurry pipeline was probably first investigated in the latter 19th century, but the first ones were successfully built and operated in the US in the early 1900s. Today, they are fairly common worldwide. Table 1 shows a number of the world's slurry pipelines. An examination of these will further emphasize the fact that pipelines provide a cost competitive alternative where new construction of a transportation system is required. In each of the examples, the desired mineral commodity is located in a remote corner of the world, markets are at a great distance, value of the commodity is not great, and no other transport system is available.

Jan 10, 1982

By G. Davis

Mineral properties and mineral firms often trade at a market value that is significantly greater than the value indicated by discounted cash flow (DCF) techniques. A possible explanation is that DCF analysis does not consider the value derived from managerial flexibility. Presumably, then, at least some of the difference between DCF value and market value is due to managerial flexibility. This paper surveys the recent attempts to empirically quantify the value of managerial flexibility using option pricing theory. The results indicate that managerial flexibility, at least as measured by the option pricing methodology, falls well short of explaining the gap between DCF value and market value.

Jan 1, 1995

By J. L. Roll

The Surface Mining Control and Reclamation Act of 1977 (SMCRA) and the regulations promulgated for that "Act" have resulted in changes to surface mining operations in order to comply with the stringent federally enforced reclamation requirements for prime farmland. In many instances the operator has modified surface mining operations to meet the prime farmland requirements through changes to mining equipment operation, addition of new equipment targeted for reclamation or the use of totally different mining techniques. The major challenge to mine operators has been how to use existing mining equipment to meet the requirements of the "Act." Freeman United Coal Mining Company opened the first new large surface coal mine in Illinois following passage of the "Act." The Industry Mine, located near Macomb, Illinois started mining operations during March of 1982 and was required therefore, to meet all of the requirements of the "Act" including prime farmland restoration. At the Industry Mine a shovel and a cross-pit bucket wheel excavator (wheel) are used for overburden removal and the wheel is addition- ally utilized to assist in reclamation operations. The wheel mines the subsoil thereby elliminating scraper placement of that subsoil and the attendant compaction problems with scraper placed subsoil. The wheel is used to convey topsoil stock- piles from the highwall to the mined overburden in order to lessen scraper traffic and possible compaction on the graded overburden during top- soil removal and replacement. Close control of the operation of the wheel yields more uniform wheel spoil ridges which then require less grading prior to topsoil replacement.

Jan 1, 1986

By Earl M. Woodward

INTRODUCTION Kerckhoff-2 is a 140 MW underground hydro-electric project designed and owned by Pacific Gas and Electric Company and constructed between May, 1980 and May, 1983 by Auburn Constructors. The project is located in the western foothills of the Central Sierra Nevada Mountains, about 30 miles northeast of Fresno, California, and develops the power potential of the lower San Joaquin River and its tributaries between the existing Kerckhoff and Millerton Lakes. The Kerckhoff-2 Project consists of project roads, adits, and access tunnels, service tunnels, power tunnels, powerhouse, tailrace tunnel surge shaft, buss shaft, intake structure, discharge structure, and switchyard. In the 1920s, the Kerckhoff 1 project, consisting of a dam, reservior, tunnel, and 34 MW powerhouse, was built in the same general area as Kerckhoff-2. The tunnel was constructed by conventional methods, and was left unlined. In time, other projects were built upstream, allowing the flow of the San Joaquin River to be regulated. The Kerckhoff 2 project is designed to harness that regulated flow, providing an additional 140,000 ON of power. Kerckhoff 2 will be the primary power plant; Kerckhoff I will produce power whenever the flow rate exceeds 4,800 cubic feet. The new power tunnel is built along the east side of the San Joaquin River between Kerckhoff and Millerton Lakes, parallel to the existing tunnel but extending approximately one mile further downstream.

Jan 1, 1983

By Karl V. Lindell

Asbestos is not the name of a distinct mineral species, but rather the commercial term applied to the fibrous form of several minerals differing widely in composition. There are some 30 known varieties of asbestos but of this number only 6 are of economic importance, and these, in order of economic significance are chrysotile, crocidolite (or blue asbestos), amosite, anthophyllite, actinolite and tremolite. Chrysotile asbestos was formed by the introduction of hydrothermal solutions into fractures in serpentinised ultrabasic host rocks. These solutions dissolved magnesium silicate from the wall rocks, and with subsequent lower temperature and pressure they became supersaturated, and crystals of chrysotile asbestos formed. The chemical composition is variable but is classified as a hydrous magnesium silicate, containing a high percentage of magnesia and water, plus varying amounts of alumina and ferrous and ferric iron. Other asbestos minerals are formed by a similar process but with a different host rock e.g. crocidolite occurs only in iron' formation. The chemical composition of asbestos minerals other than chrysotile, shows a wide variation, but in general may be classified as silicates, or metasilicates, containing varying amounts of calcium, magnesium, sodium and iron.

Jan 1, 1964

By J. C. Irvine

Meramec Mining Company is a joint venture by Bethlehem Steel Corp. and St. Joe Minerals Corp. which mines and pelletizes iron ore at the Pea Ridge Mine. The Pea Ridge property is located near Sullivan, Missouri, about 70 miles southwest of St. Louis. The orebody was delineated in the mid-1950's by St. Joe during a lead exploration program. The first test holes drilled on the Pea Ridge magnetic anomaly revealed the presence of a large magnetite deposit; further drilling in 1956 and 1957 confirmed that the orebody was mineable, Meramec Mining Co. was incorporated in 1957 and shaft sinking began late in the year. Production commenced in April 1964. The orebody is overlain by about 1300 feet of flat-bedded sediments. It is tabular, about 2600 feet long and up to 600 feet thick. It dips about 80° and is of unknown depth. The ore is mainly high grade magnetite with small zones of specular hematite. The wall rock is a Precambrian rhyolite porphyry. The mine was initially started with five major levels on 150 foot intervals. Crosscuts were driven across the orebody on 190 foot centers. Banks of scopes were mined between the crosscuts by a modified shrinkage stoping method. This was done by undercutting a 40 foot wide by 150 foot long block and blasting horizontal "lifts" drilled on 5 foot intervals. A 65 foot still was left between levels which contained the slushing drift, fingers, crown pillar, and adequate thickness for support. By 1971 a ?lattice? of pillars had been left and mining had progressed to the point that an orderly pillar recovery program was necessary.

Jan 1, 1976

"Twin Creeks is a gold mining complex that is part of Newmont’s Nevada operations. The mining complex is composed of two openpits, Mega and Vista, external ore sources and a set of existing stockpiles, all of which provide ore for an autoclave, an oxide mill and a heap leach. Mega pit provides sulfide ore for the autoclave, whereas Vista pit provides oxide ore for the oxide mill and the heap leach. Both pits operate the same mining equipment and their extraction sequence must, therefore, be optimized simultaneously. Stringent blending requirements are associated with the operation of the autoclave for the sulfide ore. Strategic blending optimization on a large scale has brought significant value to the operation by increasing synergies. This paper presents the implementation of a stochastic optimization framework for the long-term production planning at Twin Creeks that simultaneously optimizes mining, stockpiling, blending and processing decision variables. The uncertainty and variability associated with the different sources of material are incorporated in the optimization model by means of stochastic simulations. The stochastic solution generated shows substantial benefits by increasing forecasted recoverable gold, leading to increased cash flows, while reducing the risk of not achieving forecasts by increasing the probabilities of meeting production and blending targets.IntroductionMine operations consist of multiple components such as mineral deposits, stockpiles, external sources, mills and autoclaves. These components represent a mineral value chain, also known in the literature as a mining complex (Montiel and Dimitrakopoulos 2015; Goodfellow and Dimitrakopoulos 2016). The material extracted from the mines flows through the different components and is transformed into sellable products. This flow of material in a mineral value chain involves complex, nonlinear transformations that render the use of industry-standard optimizers difficult. Furthermore, the optimization of a mining complex can be formulated as a mixed-integer, nonlinear optimization program with millions of integer variables representing mining, blending, stockpiling and processing decisions, prohibiting the use of conventional nonlinear optimization approaches. Previous methods that consider the joint optimization of multiple components of the mineral value chain are available (Hoerger, Seymour and Hoffman, 1999; Chanda, 2005; Stone et al., 2005; Wooller, 2005; Whittle, 2007, 2010; Bodon et al., 2010). Although these methods add value by increasing the synergy between the different components of the mining complex, they rely on simplifying assumptions that constrain their efficacy, while ignoring a most critical aspect. The latter aspect includes the geological uncertainty and actual variability of the materials in the mineral deposits mined and are supplied to the related mineral value chain, similarly to conventional life-of-mine planning methods used for individual mines (Dimitrakopoulos, Farrelly and Godoy, 2002; Godoy and Dimitrakopoulos, 2011; Spleit and Dimitrakopoulos, 2017). Additional simplifying assumptions may include: the consideration of a limited number of components, the combination of different methods, the aggregation of variables, fixed production schedules the definition of policies prior to optimization, such as cutoff- grade definition or destination of mining blocks, the linearization of nonlinear transformation functions and/or the disregard for the uncertainty of several critical parameters (Whittle, 2007). The simultaneous optimization of multiple components of a mining complex was introduced by Newmont. Hoerger, Seymour and Hoffman (1999) implemented a mixed-integer programming formulation to optimize Newmont’s Nevada operations. The model is based on the work of Urbaez and Dagdelen (1999) and simultaneously optimizes the extraction of materials from multiple deposits and the delivery of ore to multiple plants, as well as as"

Dec 1, 2018

By Andrew T. Zador

The growing demand for energy combined with the need to protect and preserve the environment have become prime considerations in the design of efficient coal handling ports and their associated stockpiles. The transportation system is analogous to a connected chain which originates at the mines and terminates at steel mills or power plants, in which the port and the stockpile reserves are a vital link. Railroad transportation costs can be minimized by rapid discharge of the cars which, in turn, requires that an adequate stockpile system be available. Ocean transport costs can be minimized by having an efficient high capacity ship loading system and sufficient quantities of coal on hand -all of which also requires an efficient stockpile system to meet shipping demands. The connector between the two modes of transportation, therefore, is the port stockyard. It is here at the interface that optimization of land utilization and materials handling equipment results in a total transportation chain that can operate as a smooth efficient system. Multiple origins of coal require the simultaneous handling of large quantities of coal of many grades. Railroad transportation logistics often limit and define the incoming arrival patterns and limited rolling stock often require priority treatment for railroad operations. The physical limitations of prime ocean frontage require that coal stockpiles be built close to residential or industrial areas which entail strict environmental controls. Large capacity, enclosed coal stockpiles for ocean shipping have not yet been considered feasible but may be forthcoming in the near future. Several have been analyzed.

Jan 1, 1978

By T. P. McNulty

During the last decade, many exhaustive studies have been made of process energy requirements for the production of various metals and materials. Some excellent technical papers and text books have resulted, and some of these are included in the bibliography of this paper. These studies were, of course, prompted by the economic pressures which resulted from the beginning of the "Energy Crisis" in 1973. Our intensified consciousness of the cost of energy led, then, to a greatly improved understanding of the energy consumption attributable to individual mining, processing, and refining steps. It is worth noting, however, that an awareness of the cost of energy is not new and that efforts to minimize this cost were an important part of sound mine and plant management practice throughout the earlier days of our industry. One only has to read a few accounts of mining operations around the beginning of this century to develop an appreciation for the cost of supplying wood, coal, fuel oil, or electric power to remote locations.

Jan 1, 1983

By Paul H. Muller

The configuration of remote seal DP cells for specific gravity measurement is described and the calculations for calibration are presented. The error induced by ambient temperature change is investigated as it relates to capillary dynamics and electronic considerations. Instrument specifications are discussed in the light of accuracy requirements and the calculation of error vs. ambient temperature is described.

Jan 1, 1984

By D. A. Longhurst

Improper size distribution of the grinding media in a multicompartment mill can be a source of many operation problems encountered. Inefficient use of the power expended for grinding, and an undesirable product size distribution are two frequent resultants. It is necessary to resize the grinding media in the leading mill compartment at time intervals related to the abrasive nature of the material being processed. In practice, this is done when time permits and with sketchy guidelines, if any. Maintenance of the grinding media size distribution can be scheduled, and would be, with a realistic method supplied to the user.

Jan 1, 1984

By Dirk van Zyl

Pad construction costs can impact the overall economics of heap leach projects. Pad construction costs for single-and double-lined pads, using various designs, are listed for a typical small and large project. Double-lined pads are now more often required by regulatory agencies. Unless such designs reduce the risk of site specific contamination significantly, the extra costs cannot be justified from an economical viewpoint. Specific attention is given to the short project life (typically five years) of heap leach projects. A few numerical examples are presented to demonstrate the overall economic impacts of these costs on economic parameters.

Jan 1, 1990

By Gregory M. Rumbaugh, Todd R. Kostecki, Christopher Mark

From 2015 to 2021, five massive pillar collapses occurred at four underground stone mines in the eastern USA. These events resulted in powerful airblasts that damaged mine infrastructure and mobile equipment, seriously injured miners, and disrupted underground travelways. Each of these pillar collapses propagated through the overlying strata, causing a subsidence sinkhole on the surface. Pillar collapses are particularly hazardous for miners because they can occur with little warning and can affect miners that are far from the pillar collapse area. The following case studies show that certain factors may increase the likelihood of a pillar collapse. For instance, each of the 5 events involved at least 12 benched pillars with width-to-height ratios (w/h) of 0.8 or less. This study elaborates on these factors and proposes a framework to assist mine operators where they identify similar hazards.

Jul 24, 2023

In this paper, response surface methodology was applied to optimize the experimental conditions for the wet grinding of synthetic rutile. The effects of parameters such as rotation speed, solids concentration and duration of grinding on grinding efficiency were systematically investigated and the process conditions were optimized, using a nonlinear regression model based on central composite design. The statistical analysis of the results showed that in the range studied, the grinding efficiency of synthetic rutile was significantly affected by the rotation speed of the conical ball mill. According to results from analysis of variance, the value of the determination coefficient (R2=0.9989) indicates that the predicted values are found to be in good agreement with experimental values. The optimized experimental conditions were as follows: a rotation speed of 350 rpm, a solids concentration of 27.31% and a grinding time of 50.31 min, respectively. Under optimum conditions, the predicted grinding efficiency of 94.79% is obtained. The experimental values from the validation experiments were well within the predicted value of the model.

Jan 1, 2011