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By Peter A. Gillett, Ian S. Clelland, J. G. S. Hynd

Today mine shaft and slope contracts include a greater amount of ancillary work such as level and pump stations, loading pockets, rotary and side dumps and connecting raises. This ancillary work requires the application of a number of construction methods often for short periods and often at short notice if the contractor is to maintain a profitable operation. In the next decade, the number of shafts that will be sunk by a boring method will outnumber those sunk by traditional methods. This will be particularly true of the deeper shafts where water problems are minimal. The increase of bored shaft work will not decrease the work completed by the shaft sinking contractor but it will change it. A greater emphasis will be placed on the speed of construction of station and other ancillary work. To meet this challenge the contractor requires full information on the ancillary work as well as the shaft work at an early date, preferably pre-bid. The two examples discussed in this paper illustrate the importance of early information. The two main factors of shaft ancillary work construction are sequence and ground support. This paper describes two examples completed recently by The Cementation Company of America Incorporated in Arizona. The first described is a Rotary Dump-Ore Pocket-Ore Pass complex and the second described is the excavation of the Main Station Level in a 2 Station-Loading Pocket-Ore Pass complex. CONSTRUCTION OF ROTARY DUMP, ORE POCKET AND PASS Introductory

Jan 1, 1976

By C. W. Chiaretta

Utah Power and Light Company's Deer Creek Mine had been developed to a point where mine ventilation efficiency had declined to an unacceptable level. Problems identified were ventilation of inactive areas, excessive leakage, and restrictions in the return and intake air ways. Mine management implemented an intensive mine ventilation improvement program to alleviate future problems with respirable dust in the working sections and diesel equipment emissions. Program objectives included sealing of inactive areas of the mine, rehabilitation of high resistance areas, and construction of additional intake and return aircourses. Applications of computer modeling techniques are used to predict the effects of ventilation changes and improvements. Improvements are then prioritized to achieve the largest efficiency increases first. Actual real time assessment of the mine environment and ventilation changes are accomplished with a mine wide monitoring computer system. The Deer Creek ventilation improvement program has more than doubled the ventilating efficiency of the mine.

Jan 1, 1990

By Li Jiuping, Zhong Gang, Chen Yong Zhang, I. Michael Gowring

The Liaoning Dahuofang Reservoir Water Transfer Project is an important development for the Department of Water Resources of Liaoning Province in northeastern China. The 85.3 km water conduit will transport water from the Hun River downstream of the Huanren Reservoir to the outlet on the Suzi River leading to the Dahuofang Reservoir. The additional water is required to sustain the growing cities of Fushun, Shen-yang, Liaoyang, Anshan, Panjin and Yingkou. The project is divided into seven contracts. Three TBM contracts comprise almost 75% of the work and the others are drill and shoot. The focus of this paper is about the creditable TBM performances achieved and some of the problems encountered by Chinese contractors; notably two having had no previous TBM experience.

Jan 1, 2007

By Micah Nehring, MEHMET KIZIL, Farzad Sotoudeh, Amin Mousavi, PETER KNIGHTS

Production scheduling in underground mines is one of the most important and complex processes in maximising the economic value of an operation over the life of the mine. Due to increasing energy, transportation, processing and smelting costs and reducing water availability, the extraction of ore deposits through underground operations has become more expensive and challenging. A potential productive and efficient solution to mitigate these issues is to integrate pre-concentration systems into the existing mining system to increase ore grades through a preliminary process of rejecting some waste before sending the ore to the energy intensive mineral processing plant. Further benefit of such systems includes the utilisation of the waste and low-grade material in backfilling of open stopes to reduce the transportation costs and surface environmental impact such as reduction of CO2 emissions and waste transportation. The objective of this paper is to present a new mathematical model to optimise the production schedule of underground metalliferous mining operations in the presence of a pre-concentration system. The proposed model optimises the production schedule and sequencing of stopes within a sublevel stoping operation. The results of this study illustrate the potential economic benefits of using a pre-concentration system prior to a mineral processing operation as a result of increased net present value.

Nov 16, 2023

By G. Pierson

Explanations of commodity price levels, or movements, commonly focus on the supply and demand fundamentals of the particular commodity, or else are assigned to speculative activity. Comparisons of metal price histories with monetary and other economic data support the argument that the supply of and demand for money are no less important in price determination than are the supply and demand of the commodity itself. That these relationships should exist is evident in the price identity and are consistent with monetary theory. The patterns developed have limited usefulness as predictors, but their recognition is essential for the construction of price scenarios for planning purposes.

Jan 1, 1996

By Yun Bai, Sarah Wilson, Michael Salcher, Mark Trim

Over the last decade more than 62 miles (100 km) of civil transport tunnels were constructed in Sydney, Australia, using the sequential excavation method (SEM). The WestConnex motorway tunnels, each stage of which used over 20 roadheaders to excavate up to 40 tunnel headings, had numerous caverns up to 100 feet (30 m) wide and 82 feet (25 m) high. SEM tunnels in North America typically have far fewer active headings. This paper examines the differences in scope and risk allocation for construction phase services, including comparison of the Permit to Tunnel (PTT) process in Australia and the Required Excavation and Support process in North America.

Jun 23, 2024

By R. Pothina

The objective of this research was to develop a mathematical model for gyratory crushers to help in the prediction of energy consumption and to analyze dominant parameters that affect this energy consumption. The development of a gyratory crusher model was achieved in the following three main stages: mathematical representation and coding of the crushing process; building an amperage constant model to derive an energy-scaling formula; and modifying the amperage constant model to represent a full-scale model. Due to their significant influence on feed-size distributions, two blasting parameters, i.e., burden and spacing, were considered. The crusher parameters that affect energy consumption were also identified. A case study of an operating dolomite mine was performed. The results indicated that by changing the burden, spacing and crusher closed-side setting, the overall (blasting and crushing) costs could be reduced by 4.7% to 7.9% annually. It can also be concluded that burden and spacing values have a linear positive relationship with the crusher energy consumption, while closed-side setting values have an inverse linear relationship with the energy consumption.

Jan 1, 2007

By J. T. Hanks

Process development is one of the principal tasks required in the course of turning an exploration discovery into a mine. Exploration geologists should have an understanding of the more important metallurgical processes and the test work required for each process. The paper discusses the important metallurgical processes, the test work and sample requirements for each, and the costs and time requirements to accomplish the testing. The limitations of reverse circulation drill samples for metallurgical testing are discussed. The level of process definition required to support engineering studies: scoping, pre-feasibility and feasibility studies are also described.

Jan 1, 1997

By H. H. Murray

Clay minerals are one of the more important industrial minerals. They are used in many products and because of different specifications may require special processing which can be either wet or dry. The clays discussed are bentonites, kaolins including ball clays, and palygorskite (attapulgite). In order to design a process flow sheet for these clay minerals, the physical, chemical, mineralogical, and optical properties need to be evaluated. Each species of clay minerals require a group of special tests which are described in this paper.

Jan 1, 2009

By Dale S. Hursh, William A. Brooks

Introduction US dependence on external energy sources is dangerous because of unstable political situations existing in key energy exporting countries. So, recent national energy policies call for increased reliance on domestic energy sources. Coal ranks as the most feasible domestic energy source due to its abundant reserves and continental distribution. But to efficiently extract these coal reserves, huge sums of capital funds are needed. Due to the depressed economy, lenders of capital funds are forced to be more stringent with loan applications. This results in fewer loans granted. In many cases, it is uncertain if funding can be obtained. Furthermore, the greatest level of domestic mine financing is expected to be in the coal sector. Demand for capital in the domestic coal industry is anticipated to increase 80% by 1990. The Chase Manhattan Bank in New York warns that these future needs cannot be met by the present capital markets. This article analyzes the current and expected situations of the capital markets available to the domestic coal industry, including: • current and expected future types of financing used in the domestic coal industry; • problems the domestic coal industry may encounter as it seeks capital; and • the future availability of capital funds as concluded from analysis of the first two items. Background Information Regardless of industry, all projects or ventures can be divided into four basic stages: generation; evaluation; selection; and execution. Within the mining industry, one can break down these stages to draw a clear picture of mine development, as shown in Fig. 1. Each successive stage has a corresponding risk level. This risk level defines the type of financing available to the mine operator. Mining Venture Risks A coal mining venture can be characterized by its unique blend of technical and financial risk. As the mine moves through different development stages, varying proportions of each of these risks are encountered. It is these risks that the lender evaluates to determine project suitability. For a coal mining venture, the major complexities generally occur with the technical risk. These include: • quantifying the coal reserves: • assessing the feasibility of the mining method; and • evaluating the design of the wash plant. The reserve risk is gauged by the amount of measured, mineable, and saleable reserves. The greater the latter amounts, the lower the risk. Secure title to the reserves plus title for any surface areas required are also of concern to the banker. Feasibility of the mining method and evaluation of the wash plant design should verify that the project can be completed according to the engineered spec-

Jan 9, 1982

By L. B. Hales

Expert control of grinding and flotation plants has been successfully used in the minerals industry since the 1970?s. The earliest of these systems were written in a hard-coded fashion in FORTRAN, BASIC or Pascal. Second generation systems were built using the first experimental expert system shells that were being developed in the artificial intelligence community. Later systems were deployed in expert systems designed for real-time processing plants that also include the ability to model the process with neural network models and optimize setpoint selection through the use of genetic algorithms. [1,2] In spite of the fact that significant performance increases have been achieved using these systems they are not perfect and can be improved. They suffer from the static nature of their rules and to a degree the process models. There is an opportunity to further increase system performance by systematically taking advantage of the tremendous amount of data produced by the expert system to improve the design, the heuristic rules, the model topologies and the use of the models. Data mining refers to extracting or mining knowledge from large amounts of data where the objective is to automatically analyze, classify and summarize the data to automatically discover and characterize trends in it and to automatically flag anomalies. [3] Clearly, modern process control systems are capable of collecting vast amounts of data. Without a doubt, these data contain important information on the operation of our plants and their ultimate optimization. Coupling the information mined from these data with Expert Control Systems should produce more effective control and greater knowledge of the grinding process and the flotation process. Now, with the advent of effective monitoring of entire minerals plant electric consumption it is possible to not only optimize plant production in real-time it is possible to analyze total plant electrical consumption and incorporate it into the plant control logic thereby improving the overall plant economic performance. This is particularly important with the ever more complex power contracts that plants operate under.

Jan 1, 2012

By Kirk Carlton

The Athabasca tar sands of Alberta are an increasingly important source of crude oil for the North American continent. Published figures indicate estimates of recoverable resources in the tar sands at some 300 billion barrels of synthetic crude of which some 86 billion barrels can be recovered by surface mining techniques. At the present time, two commercial plants are in operation, Great Canadian Oil Sands Limited and Syncrude Canada Ltd. Their present combined capacity is approximately 150,000 barrels per day. Some of the factors which will make this oil expensive will be noted here. The location of the present producing plants is 500 kilometres north of Edmonton at an elevation of approximately 320 metres. Recorded temperatures range from +38 to -55 degrees Celsius. Wind velocities are not high but the chill factor with even a slight breeze and minus 40 degrees is very uncomfortable.

Jan 1, 1979

By J. Warmbrodt, D. Apel, D. Nutakor, L. Grayson, M. Hilgers

MinerSIM is an augmented reality system with integrated hypermedia that is suitable for training underground miners in the basics of using a jackleg drill to install rock bolts. While statistical evidence shows that rock bolting with such a drill has an inherent level of risk, it is conjectured that this can be mediated with adequate safety training outside of the actual mine environment using a variety of educational media including interactive three-dimensional images, games, animations, and videos to describe the mechanics of rock bolting and its principles. Ultimately, trainees will install rock bolts in an immersive environment mixed with real and virtual images generated via a gaming graphics engine. This paper will discuss considerations, implementation issues, and evaluation methodologies of the MinerSIM system.

Jan 1, 2007

By Juan L. Sepulveda

An MPSI KW-20 Tower mill has been tested at the Butte Molybdenum plant of Anaconda Minerals Company, as a substitute for the conventional 1.5x3.0 m (5x10 ft) tumbling ball mill currently used for regrind purposes. The Tower mill was operated in both open and closed continuous circuits. These results were complemented with a series of batch grinding tests to determine some of the operational features of this mill. The relative grinding efficiency of the Tower mill with respect to the tumbling ball mill was determined and the applicability of this new mill to a plant/heavy duty environment was assessed. Experimental results obtained on the regrind of moly concentrates indicate that approximately 40% energy savings can be realized by using the Tower mill instead of the ball mill.

Jan 1, 1984

By A. Balint

The Photometric Optical Separation process is introduced and examples of sorting machines are given. Applications of the process are outlined in general terms with reference to specific types of industrial installations. Brief description is given of the capabilities and limitations of available equipment, including cost estimates.

Jan 1, 1967

By E. McCullough, S. Gaillard

"Diesel particulate matter (DPM) remains a health concern in many underground metal/nonmetal mines, and has been regulated by the Mine Safety and Health Administration since 2002. While the NIOSH 5040 standard method for DPM monitoring is required to demonstrate regulatory compliance, the FLIR Airtec DPM Monitor can serve as complementary engineering tool. It is a handheld instrument that offers near real-time measurements. As part of an ongoing field study, the Airtec has been used to survey elemental carbon concentrations (a proxy for DPM) in an underground stone mine. Via “spot-checking” and more prolonged area monitoring, this effort was aimed at determining spatial and temporal DPM variation in several key locations. INTRODUCTION Diesel particulate matter (DPM) is the solid fraction of the exhaust emissions from a diesel engine. It is largely made up of elemental and organic carbon (EC and OC, respectively), which can be measured as proxies for estimating mass concentrations of DPM. The National Institute for Occupational Safety and Health (NIOSH) considers DPM to be a health hazard and potential carcinogen [1]. It is believed to cause and/or exacerbate respiratory illness upon inhalation, deposition, and retention in lung tissue [2]. Since DPM exists in both the micro- and nano-particulate ranges, it can surpass typical auto-immuno defense mechanisms that keep larger particles out of the respiratory system [2]. Relative to other occupations, the DPM exposure potential for underground miners is high because these individuals work in enclosed environments where diesel powered equipment is frequently used [3,4]. A variety of engineering and administrative controls have been devised to reduce DPM exposures in underground mines, and increased airflow is often a key component of control strategies. In large-opening mines, which are most common in the metal/nonmetal sector, DPM abatement via increased ventilation can be especially complex due to moving and controlling the large air quantities [5]. The Mine Safety and Health Administration (MSHA) has regulated DPM exposure in metal/nonmetal mines since 2002. The final rule limits personal exposure to total carbon (TC, which is the sum of EC and OC) to an eight-hour time weighted average (TWA) of 160 µg/m3. To demonstrate compliance, operators must use the NIOSH 5040 Method [6]. However, the Airtec DPM Monitor (FLIR Systems, Inc., Nashua, NH) was developed as an engineering tool to provide near real-time measurements of both EC and TC for tracking personal exposures [7]. The portable Airtec works by capturing DPM on a filter and successively measuring laser extinction on the filter as DPM accumulates; the EC fraction of the DPM is dark, and so as it accumulates the filter becomes darker and absorbs more laser light [8]. The laser extinction value is directly correlated to EC, but since EC and TC are generally observed in consistent proportions (i.e., TC = EC*1.3), the Airtec is also programmed to display TC as a TWA [9]. There have been multiple studies conducted to validate the Airtec and the instrument has been adopted by some mine operators as a tool for their health and safety programs [3,8]."

Jan 1, 2016

By P. M. Soupios

An integrated suite of environmental methods was used to characterize the hydrogeological, geological and tectonic regimes of the study area, to determine the geometry of the landfill (depth and spatial extent of electrically conductive anomalies), to define the anisotropy caused by bedrock fabric fractures and to locate potential zones of electrically conductive contamination. The study area which covers an area of about 0.08 Km2 is a municipal solid waste site (MSW), located 20Km West of Herakleion in the central part of Crete (S. Greece). The landfill is located in a northwest oriented valley with highlands to the northeast and southwest. The combination of geophysical methods and chemical analysis are commonly implemented for characterization and management of land-fills. At the particular site, geophysical methods were focused on studying the electrical insolating properties of the materials, electrical con-ducting properties of fluids (leachates) and electromagnetic properties of the disturbed regolith materials in the burial zones. Three different types of geophysical surveys were performed: 1) 2D electrical tomography (ERT), 2) electro-magnetic measurements using very low frequencies (VLF) and 3) electromagnetic conductivity (EM31). Furthermore, in order to calibrate the geophysical methods dielectric spectrometry measurements are conducted. To evaluate the environmental degradation of the area, soil and liquids samples were collected.

Jan 1, 2005

By P. Roghanchi

The difficulties associated with performing direct tensile strength test lead to development of indirect test methods, which are simple, less expensive, and less time consuming. Splitting tensile strength test (Brazilian test) is performed by applying two opposite concentrated compression load across the diameter of a disk specimen until the failure occurs along the loaded diameter. Theoretically, the load is applied over a small width as a line load, however, by increasing the load, the contact width between the loading jaw and the specimen increases as the specimen deforms. The main aim of this study is to investigate the stress distribution in (1) regular Brazilian specimen in traditional tests with loading jaws and (2) flattened Brazilian specimen with flat platens. A series of the splitting tensile strength tests and uniaxial compression strength tests are performed on three rock types: rhyolite, basalt, and limestone. Further, Numerical modeling studies are performed to investigate the effect of the contact between jaw and Brazilian specimen on stress distribution in the disc specimen based on the results from the experimentation. Finally, the stress distribution in the traditional Brazilian test specimen and the flattened end Brazilian test specimen were compared.

Feb 23, 2014

By D. Seneviratne

Iron transfer from the pregnant leach solution (PLS) to the electrolyte can have a major economic impact on solvent extraction (SX) operations. High iron transfer will lead to greater operational costs, due to increased reagent consumption through electrolyte bleed and make up, or increased power costs due to decreased electrowinning current efficiency. Bioleaching of low-grade copper sulfide ore from the Kennecott Utah Copper Mine was investigated in a large scale piloting program including SX and electrowinning. Plant data and lab test work conducted throughout the course of operation, show that the unique containing PLS high ferric iron with high pH can lead to lower Cu: Fe selectivity than is typically seen in traditional copper SX operations. The impact of high ferric iron on the plant operation, and methods to reduce iron transfer will be discussed. Special considerations need to be taken for plant operating conditions and selection of SX reagents (including both extractant and aromatic content of diluent) based on the feed PLS characteristics.

Feb 23, 2014

By Gregory M. Rumbaugh, Christopher Mark

"The proliferation of unconventional gas well development in the Northern Appalachian coalfields has raised a number of mine safety concerns. Unconventional wells, which extract gas from deep shale formations, are characterized by gas volumes and pressures that are significantly higher than those observed at many conventional wells. The gas is composed largely of methane as well as other hydrocarbons. Hundreds of planned and actively producing wells penetrate protective coal pillars or barriers within active mine boundaries, including chain pillars located between longwall panels. Gas released from a well damaged by mining-induced ground movements could pose a risk to miners by flowing into the mine atmosphere. The mining-induced ground movements that may cause well damage include conventional subsidence, non-conventional subsidence (e.g., bedding plane slip), pillar failure, and floor instability. This paper describes the known risk factors for each of the four failure mechanisms. It includes a framework that can guide the risk assessment process when mining takes place near gas or oil wells.INTRODUCTIONSouthwestern Pennsylvania has served for centuries as a producer of coal, oil, and natural gas. Coal mines were first developed in the Pittsburgh Coal Seam in the 1760s, with the first recorded mine in 1761 being the Fort Pitt Mine (Edmunds, 2002). Natural gas was introduced to the region when the Haymaker Well in Murrysville, Pennsylvania experienced a blowout on November 3, 1878. Although it was originally drilled prospecting for oil, it produced an estimated 30 million cubic feet per day of natural gas. Without well controls or pipeline infrastructure in place, it burst into flames and lit the night sky for over a year. Soon after, the Penn Fuel Company continued development of the Murrysville gas field and is credited with making Pittsburgh, Pennsylvania the first major city in the U.S. to have natural gas supplied for home and industrial uses. “Natural gas is king in Pittsburgh,” proclaimed an October 18, 1885, article in the New York Times headlined “Value of Natural Gas, Its Use Clarifies the Atmosphere at Pittsburgh” (AOGHS, 2018). By the early 1900s, coal, oil, and natural gas production had reached the southern extents of Pennsylvania in Greene County. The county had first produced oil in 1886, and shortly after began producing natural gas in 1890. By 1906, over 1,300 wells had been drilled (Stone and Clapp, 1906)."

Jan 1, 2019