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By Josiah Pohl, Christopher Utter, Kyle Everly, Akshay Chowdu

Battery Electric Vehicles offer increased energy efficiency for open-pit load & haul operations at a potentially lower overall carbon cost. Electrifying a mine’s fleet, however, presents a unique set of operational challenges. In this study, we explore the effects of electrification on productivity at real operations using a Discrete Event Simulator. The model can simulate multiple shifts, a mixed fleet of diesel and electric trucks, charging and refueling stations, trolley systems, and accurate shovel-truck loading cycles. This study helps determine the trade-offs of adopting electric fleets and how they interact with the layout of today's mines.

Jun 25, 2023

By Atmesh K. Sinha

The market for thermal coal has recently been growing rapidly and it is projected to continue to do so in the foreseeable future. Both the national and international markets often demand high Btu low sulfur thermal coal in order to minimize the cost of utilization and meet the environmental restrictions. High quality thermal coal can be prepared to compete in the utility market by desulfurizing the high Btu midwestern coal and blending it with low sulfur western coal which is usually low in Btu content. The methods that can be used for optimizing the coal preparation plant operating parameters for physically desulfurizing coal is presented.

Jan 1, 1984

By Sam M. Pickering

Most high, purity silica is produced from crystalline quartz-generally from sand. However, there is a small area of southern Illinois where a porous, friable white chert rock is found which is very different in physical form from quartz sand. This microcrystalline material, commonly referred to as tripoli, is more easily ground to micron sizes than sand. Although of similar Moh's hardness, microcrystalline tripoli is less abrasive than either ground quartz sand or many synthetic abrasives. Location The southwestern corner of Illinois is underlain by extensive deposits of very porous chert; in some places the material is quite white. Two companies - Illinois Minerals Co. and Tammsco, Inc. - mine and process this white material. The Illinois Minerals plant is located at Elco, and the Tammsco plant is in Tamms, Illinois. Both companies mine from various locations within a ten mile truck haul of their plants. Production from this district has been continuous since at least 1915. Malvern Minerals Company mines and processes a generally similar microcrystalline, friable novaculite near Hot Springs, Arkansas.

Jan 1, 1985

By Augusto Andres Torres Toledo, João Felipe Coimbra Leite Costa, Luciano Nunes Capponi, Diego Machado Marques

Short-term mine planning to open pit requires defining diglines to orientate the excavation geometry. In deposits with multiple chemical variables, it is necessary to have more rigorous control over the feeding of the processing plant. This study analyzes the impact of incorporating multiple chemical variables, the risks generated by geological uncertainty, and the number and starting point locations of shovels in the sequential design of diglines. The objective is to maintain and preserve the low-grade variability, required tonnage, and continuity in sequentially selecting blocks. To achieve this, the probability distribution function of each chemical variable is used while attempting to maintain the ore grades as constant as possible. As it is difficult to maintain multiple elements with low variability simultaneously, the relevance of each chemical variable in the economic benefit is identified. Weights are assigned to signal the importance of each element based on its significance in the recovery process. Several diglines, consisting of sequential blocks, were generated on the same seed point to meet the weekly ore demand. Optimizing the stationarity of multiple chemical variables, accessing and reducing the geological uncertainty performed through geostatistical simulation of grades and transfers functions, considering the number and location of shovels, while meeting the operational restrictions of the selected blocks. The optimized digline with the multiple grades as stationary as possible is retained. The process is illustrated in a phosphate mine. The results show that the proposed method is viable and allows for a quick solution.

Jun 25, 2023

By D. L. Whiting

Dump leaching and ,in-situ solution mining have received considerable attention during the past few years due to their apparent economic viability and minimal environmental impact. Solution mining actually dates back to the 17th century when leaching of copper ore was first reported. However-, modern day leaching didn't begin on a wide scale until the mid-1900's. In-situ mining for copper, nickel, salts, and oil shale is currently looking more attractive as the technology advances. Presently, about 15 percent of the copper production in the United States is from leaching operations at approximately 14 active sites, the largest of which are the waste dumps near the Bingham Copper Mine, Utah. To establish a common background, the discussion is centered around state-of-the-art conditions. For dump leaching, complications inherent to the physical conditions and chemical reactions such as channeling, porosity and permeability, sorption, air flow, rock alteration and pH control are discussed. Emphasis is made on those conditions which render solution recovery rates and solution mineral concentrations unpredictable. By illustrating typical and actual field conditions, the generally accepted flow theories for both dump leaching and in-situ solution mining, including rubblization, are presented. For in-situ mining, hydrogeologic techniques such as geophysical well logging, aquifer testing and digital computer modeling are also discussed. The importance of artificial fracturing and well stimulating to solution injection and recovery is made with regard to project development. Finally, the subject of water pollution control techniques and the potential impact of the

Jan 1, 1977

By Dolf W. Fieldman

Most recently the geologic setting of the mineral deposits in the Silver Cliff district is described by William M. Sharp in ?Geologic Map of the Silver Cliff and Rosita Volcanic Centers, Custer County, Colorado?, (U. S. G. S. Map I- 1081). The discussion will relate only to the southern half of the Silver Cliff volcanic center and differences in geologic interpretation, which are largely structural, will be pointed out as they arise. Only the manganese/silver zone of the Kate Area will be discussed in detail.

Jan 1, 1980

By Ernest Y. Baafi

The technique of linear kriging as a grade estimation method of mining blocks is reasonably established in the mining industry. Because of the nonbias condition imposed in kriging which requires that the kriging weights (?i) add up to one, negative weights are sometimes used in kriging. The use of negative weights is not justifiable from the practical standpoint. Also, negative block grades can be obtained in some extreme situations which makes no practical sense. To guarantee non-negative weights an additional constraint is required in the kriging system of equations. Unfortunately, the nonnegative weight constraint results in a set of non- linear system of equations. In this paper, a derivation of the resulting set of nonlinear equations is presented and a numerical algorithm is developed for the solution of the equations. Because the algorithm developed does not remove negative weights arbitrarily, optimal nonnegative weights are always guaranteed. Results obtained using the developed algorithm were compared with those using the standard linear kriging, in terms of computer time and the estimation results. Both the computer time and the kriging variance were found to be higher with nonnegative constraint, as expected. However, some systematic pattern was observed in the kriged values (i.e., over or under estimation) with or without the nonnegative constraint. The study also demonstrated when one should generally expect negative kriging weights in practice, and what practical impact the negative weights can have on the kriging estimates.

Jan 1, 1984

By Mohan Dutt

This paper is concerned with applied platinum resistance thermometry which involves many considerations absent in precision thermometry. The historical development of the Callendar-Van Dusen Equation which describes the resistance- temperature relation of pure platinum is discussed. The advantage of using platinum resistance temperature sensors over thermocouples is described, and the improvements in design and construction of these sensors that have come about in the past few years are discussed. Integral and remote bridges that convert resistance changes into voltage together with signal conditioning techniques and equipment for voltage or current signals are described. Errors encountered in temperature measuring schemes and methods to reduce these errors are summarized.

Jan 1, 1969

By Donald J. Olson, Thomas J. Lutzenberger, John Ramage

The North Shore Inline Interceptor, Phase IA tunnel is a 8,550-meter (28,000-ft) interceptor tunnel currently being constructed by Traylor Bros./Frontier-Kemper, Joint Venture, using a 9.8-meter (32-ft - 4-in) diameter Robbins tunnel boring machine (TBM). This tunnel is being driven in Silurian age dolomite approximately 91.5 m (300 ft) below ground surface. Significant water inflows were encountered when the tunnel drive penetrated the thinly-bedded Waubakee Formation. Flow increases approaching 0.75 cu m per min per 30 m of tunnel (200 gpm per 100 ft) have occurred in this formation. After driving approximately 2,285 m (7,500 ft) of tunnel (200 m full face in the Waubakee Formation), total flows exceeded 12 cu m per min (3,200 gpm) with about 5.7 cu m per min (1,500 gpm) entering the tun¬nel from the 200 m (600 ft) of exposed Waubakee Formation. Additional water control measures consisting of increased pumping capacity, increased water treatment capacity, surface grouting ahead of the tunnel, grouting ahead of the tunnel face and panning to improve the working environment for installation of tunnel support, were implemented to deal with the large water inflows. Currently (January 24, 1989), 3,400 m (11,000 ft) of tunnel has been driven, total water inflows are in the range of 11.7 cu m per min (3,100 gpm) with only 6.8 cu m per min (1,800 gpm) inflow from about 1,220 m (4,000 ft) of tunnel driven full face through the Waubakee Formation.

Jan 1, 1989

By Gregg Sherry, Bob Gordan

INTRODUCTION This paper report presents the general case history for the construction of the North Outfall Replacement Sewer (NORS) project. A 1982 City of Los Angeles Wastewater Facilities Plan recognized that a 19.3 km (12¬mile) section of the North Outfall Sewer (NOS), from Culver City to the Hyperion Treatment Plant, was deteriorating and had insufficient capacity. Built in the 1920s of unreinforced concrete and lined with vitreous clay tiles, the originally unventilated NOS suffered considerable corrosion by H2S gas. This caused roof tile and concrete to fall to the bottom of the pipe, which, over the years, reduced the 11.9 M3/S (420 cubic feet per second (cfs)) design capacity of the NOS to a current level of approximately 8.5 M3/S (300 cfs). This worsening condition, thereby contributing to the polluting of Santa Monica Bay. This situation culminated in the State of California Regional Water Quality Control Board, Los Angeles Region, issuing a Cease and Desist Order on January 27, 1986, which required the City of Los Angeles to eliminate such dry weather overflows through a number of prescribed actions. One of these was to construct the North Outfall Replacement Sewer (NORS) by April 1, 1993. PROJECT DESCRIPTION The NORS Project involved the construction of over eight miles of tunnel and related structures. It consisted of a main tunnel conduit to convey sewage to the Hyperion Treatment Plant and four diversion lines connecting the main tunnel to major existing

Jan 1, 1993

By E. Fregeau-Wu

To recycle steelmaking slags for their iron, manganese, and lime contents, removal of the phosphorus-bearing dicalcium silicate and calcium phosphate is essential. Slow-cooling of slags was necessary to promote the sufficient grain growth to achieve liberation. In-situ grain size distribution determination showed that a high soaking temperature, a long soaking time, a very slow cooling rate, and the addition of fluorspar were shown to promote grain growth. High gradient magnetic separation on slow-cooled slags removed much of the dicalcium silicate. Liberation modelling was used to discuss the breakage and beneficiation characteristics of the slow-cooled slags.

Jan 1, 1992

By C. B. Manula

This paper presents the results of an application of the PSU/USBM Open Pit Materials Handling Simulator (1) to a large stripping mine in the Southwestern Coalfield. The specific objective of the study was to demonstrate the application of the simulator to a complex multi-pit operation, with emphasis on simulating short term and long term production plans recommended for the mine by Theodore Barry Associates (2). Mine Description The mine is located in the Southwestern Coalfield, which encompasses parts of the states of Utah, Arizona and New Mexico. The lease area presently covers 121500 x 103 m2 (30000 acres) in a strip 37.007 x 103 m (23 miles) from north to south and up to 1609 m (1 mile) in width, located at an elevation above 1525 m (5000 ft). Three gently dipping coal seams are present, of which the upper seam (#3) averages 0-5.5 m (0-18 ft); the intermediate seam (#2) averages 0-1.2 m (0-4 ft); and the lower seam (#1) averages 0-2.4 m (0-8 ft). Overburden is mixed sand, gravel, calcareous clay, caliche and sandstone, with calcareous shale and sandstone burden between seams. Where the seams are covered by less than 6.1 m (20 ft) of overburden, they are generally weathered and oxidized and are not extracted. Stripping ratios have ranged from 3.5 to 6.0 with an average of 5.4. All future plans were based on a stripping ratio of 5.3.

Jan 1, 1979

By Peter L. Hofmann

Significant quantities of nuclear wastes were first generated in 1944 as a byproduct of the national defense program. To establish the current inventories and future projections of nuclear waste products is not a simple task. The Oak Ridge National Laboratory recently issued a report which now constitutes the official basis for nuclear waste inventories and projections. Radioactive wastes originate from five major sources (U .S. Department of Energy, 1980b) : (1) From the commercial nuclear fuel cycle related to the production of electricity , (2) From defense related activities, (3) From institutions such as hospitals, universities, and research foundations, (4) From industrial uses of radioisotopes, and (5) From mining and milling of uranium ores.

Jan 1, 1981

By R. Hendrickson

In the 1940's a top blown water-cooled oxygen lance was developed to inject oxygen into liquid iron. This process, the LD or BOF process technique, today is used in 65% of the world's steel production, and represents the largest oxygen market for temperature enhancement in steel and non-ferrous smelting applications. There are three major approaches to the use of oxygen in metallurgical processes: (1) general enrichment of the air supplied to burners or tuyeres, (2) under-flame enrichment or injection, and (3) the use of an auxiliary oxy-fuel burner as a heat source. With each of these techniques there are technical and economic trade-offs.

Jan 1, 1990

By David W. Wisecarver

The U.S. Bureau of Mines, in cooperation with U.S. Borax and Chemical Corporation and the Kennecott Copper Corporation, has investigated the use of the microseismic method to evaluate the stability of large, open-pit slope walls. The method is based on the phenomenon that stressed rock normally emits subaudible rock noises, and the number of rock noises per unit time (noise rate) and the magnitude of the rock noises (amplitude) increase as the stresses in the rock approach the failure stress of the rock. Therefore, the detection and recording of those rock noises serve as a semiquantitative method of predicting the incipient failure of rock. This report briefly describes the three different types of microseismic apparatus, the procedures, and the results of microseismic investigations in the slope walls of the Boron Mine near Boron, California, and the Rimbley, Liberty, and Tripp-Veteran open-pit mines near Ely, Nevada. Microsesimic noise rates in stable inactive mining areas are between 0 and 10 noises/ hour; the rates in stable active mining areas are between 10 and 50 noises/hour; and the rate in unstable areas is as high as 2500 noises/ hour. High microseismic noise rates in the Liberty Pit correlate with the time of nearby earthquakes, indicating that the earthquakes affected the slope wall. The results provide evidence that the microseismic tech¬nique is applicable to large pit walls, and that the wide band, wide range microseismic equipment appears to be suitable for open-pit investigations.

Jan 1, 1969

By Osvaldo A. Bascur

Most mining and metallurgical plants have developed predictive maintenance policies based on statistical analysis and special techniques, like vibration analysis, oil and lube analysis for critical equipment. Process control strategies have also been installed in several metallurgical sites. These control strategies require instrumentation maintenance from local personnel. The availability of real time and process history to identify the most critical part of the processing system from mechanical integrity is a must for global plant optimization. Specialized performance control monitoring algorithms are required to justify their existence and contribution to the bottom line. Emerging technologies are combining these techniques into a single total plant system. Tools are required to assist in troubleshooting and adapting these process control instruments and strategies. The key is the plant equipment and process control availability and utilization rather than just maintenance.

Jan 1, 1997

By Suprakash Gupta, Pawan Kumar Yadav, Deepak Kumar, Debasis Jana

Draglines are extensively used in Indian mines. A dragline has more than hundreds of components, and it is complex in design. This study involves the evaluation of the reliability of a draglines system using a Bayesian network (BN) model mapped from a fault tree. Based on the BN inference, the reliability estimation, the diagnosis, and the sensitivity analysis are performed. In this paper, the overall reliability of the dragline is estimated as well as the contribution of the subsystems or components in the overall reliability evaluation is presented. The results showed that the three subsystems of the dragline, namely, the dragging mechanism, electrical auxiliary subsystem, and swing mechanism, have the lowest reliability (82.17%, 87.98%, and 91.30%, respectively) after an hour of operation. The overall reliability at the first hour of machine operation is estimated to be 62.03%. The study may provide a reference for future work related to the dragline machine’s reliability design and maintenance.

Jan 14, 2023

By John E. Butler

Due to the present economic climate, particularly the depressed copper market, conventional mining, milling and flotation operations have been suspended. However, due to the apparent amenability of the ore to 'natural' leaching, investigations have been initiated into establishing an in-situ leaching operation as a preferred alternative to conventional operations. Cement copper production has been developed in parallel with the leaching trials and is presently at the rate of approximately 3,000 tonnes of contained copper per annum. Testwork includes controlled leaching of ore both in the laboratory and in-situ following blasting.

Jan 1, 1981

By D. B. Sikka

Porphyry type copper ± molybdenum deposits typically occur in the Phanerozoic rocks and have been well documented. During the past two decades a number of porphyry type Cu ± Mo deposits which range in age from 1055 ± 35 Ma to 2970 Ma have been identified in the Precambrian rocks of Australia, Canada, China, Finland, India, Namibia and Zambia. Kalanjkhand porphyry copper deposit M. P., India which is estimated to contain 789 million tonnes averaging 0. 83 percent Cu (millhead-grade); 0.004 percent Mo; 0.2 gm/t Au; 6 gm/t Ag and a cap of 7.532 million tonnes of oxide are averaging 0.8 percent Cu. The economic potential of the expanded copper mining milling, smelting and refining complex to be built in the future at Kalanjkhand, which is the largest porphyry copper deposit discovered to date in the Precambrian rocks of the world is presented.

Jan 1, 1992

By Lawrence Adler

The properties of a geologic mass may be considered from a resource or an engineering viewpoint. The primary engineering applications include ground control, excavation, bulk handling, and hydrology. This study will focus upon these areas in descending order. For an adequate geologic description, data is necessary on the following components: (1) the intact rock, (2) geologic structures, (3) contained fluids, and (4) existing pressures and temperatures, see Table 1. This information, combined with the engineering specifications, provides the basis for a formal geotechnical analysis as illustrated in Figure 1. For a structural analysis it is essential to establish the mechanical properties of the material composing the structure. This material, termed the "rock mass," consists mainly of the first two geologic components, the intact rock and geologic structures (Figure 1) Consideration of fluids will be subordinated to their role as chemical agents affecting the mechanical properties. The existence of pressures and temperatures generally lies beyond the scope of this study.

Jan 1, 1973