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By Craig Bournes, David Chapman, Michael DiPonio

Historically, boulders are a frequent source of problems in soft ground tunneling. During tunnel construction, the need to manually break and remove boulders as obstructions causes delays to the project. Repairs to a tunnel boring machine (TBM) can also be a source of delays. Managing these problems is difficult since normal soil investigation techniques do not accurately predict the presence or frequency of boulders. This has lead to considerable number of claims for extra costs and delays during the construction of soft ground tunneling projects. These issues are exacerbated in pressurized face tunneling systems where there is limited access to the TBM cutterhead for obstruction removal and/or cutterhead maintenance. The project team that built the Big Walnut Augmentation/Rickenbacker Interceptor (BWARI) Project for the City of Columbus successfully managed the design and construction of a 4,267 mm (14 ft) diameter soft ground tunnel with high boulder concentrations in a complex geologic setting. The management of the boulder issue tookplace during several phases of the project.

Jan 1, 2007

By G. R. Brunskill

The molybdenite flotation plant at the Magma Copper Co. San Manuel concentrator has been in operation since 1956. In January of 1980, the plant was converted from a hydrogen peroxide-ferrocyanide process to the current sodium cyanide-sodium hydro- sulfide process. This paper is an operational review of Magma Copper Co.'s molybdenite recovery circuit, column cell flotation experience, and use of on-stream X-ray fluorescence analysis.

Jan 1, 1987

By M. Tapper

If one considers that prehistoric man's first house may have been a limestone cave, calcium carbonate may be the most timeless of all building materials. Fanciful history aside, CaCO3 has been used for countless applications in human habitats. After all, tine marble block and tiles have always been the hallmark of eloquents and style. Mortars and cements derived from limestone have held together the very blocks of our civilization. In modem times, synthetic polymers are blended with ground limestone to produce everything from pipe, floor tile, cultured marble and house siding. All of these miracles of our technology contain CacO3 of various sizes and in varying amounts. This paper will discuss some of the critical attributes of CaCO3 which make it suitable for the new building products that have helped increase our standard of living. The vehicle of discussion will be a residential, single family house.

Jan 1, 1993

By H. Dho

The role of sodium silicate in the anionic flotation of a Florida phosphate ore was investigated using laboratory continuous flotation tests, frothability tests and SEM observations. In the absence of sodium silicate, Ca++ promoted the unwanted activation of quartz by forming calcium bearing precipitates. The addition of sodium silicate enhanced the flotation efficiency through: (1) the removal of impurity minerals and calcium-bearing. precipitates from quartz surfaces by dispersion, (2) drier and more persistent froths stabilized by oily droplets containing calcium silicate precipitates, and (3) higher specific flotation rates of phosphate relative to quartz, leading to faster flotation rates and increased selectivity of separation.

Jan 1, 1990

By J. Routh

Analysis of AI, As, Ba, Be, Ca, Cd, Co, Cu, Fe, K,. Mg, Mn, Mo, Na, Ni, Pb, Sb, Se, Sr, 11, V and Zn in various types of samples collected at Van Stone mine (a Pb-Zn deposit in Washington) and surrounding areas indicates that the concentrations of several elements in water, soil and sediment are higher than their background. values. Concentrations of metals in water decrease sharply downstream and are below the maximum contaminant levels specified for drinking water. Under present physico-chemical conditions, contamination of water is insignificant but the enrichment of heavy metals is found in soil and sediment.

Jan 1, 1994

By S. S. SHINDE, P. C. JIKAR, N. B. DHOKEY

Mill scale is an oxide waste product of the steel mills, which contains around 70% iron and other allied impurities. In the present context, a dynamic prototype counter current reactor (CCR) has been used for experimentation and simulation of particle bed by using discrete element method (DEM). Mill scale was pulverized to ASTM mesh range 140 (106 μm)/ + 270 (53 μm), and then it was oxidized in CCR to make single oxide Fe2O3 phase by maintaining required thermodynamic conditions such as pure oxygen at 1100 °C. Then this oxidized powder was subjected to reduction reaction in CCR having gas mixture ( H2:N2) ratio of 1:4 at 875 ± 5 °C for filling degree (fd) and reactor revolution (ω) ranging from 5.38 to 16.14% and 2 to 5 rpm, respectively. A creeping fluid flow condition (Re ˂ 1) and natural heat convection (Gr/Re2 ˃˃ 1) has been maintained while undergoing solid–gas reaction. Besides particle bed behavior has been quantified by Froude number (Fr) for the optimum operating window. The simulation was validated by the experimental results of reactor reaction product by X-ray diffraction (XRD) and scanning electron microscope (SEM) images. Prevailing heat transfer mechanism and reduction reaction mechanism has been established for solid–gas counter current conditions.

Nov 22, 2021

By Milka Madahana, John Ekoru

Particulate matter is one of the leading pollutants in the mines and in the communities in the areas near or surrounding the mines. The availability of large Clinical and environmental data sets obtained from the mines has brought about the need to use better approaches to analyze the collected data. Prediction and control of particulate matter concentration in the mining environment is essential in minimizing air pollution and protecting the respiratory health of mine workers. The main objective of this research work is to analyze datasets obtained from a mining area using machine learning techniques which will then be followed by the real-time estimation of dust particulate in the mines. Datasets collected over 8 years in an hourly sampling rate from an open cast mine is cleaned and analyzed for trends and patterns. Artificial Neural Networks (ANNs), Support Vector Machines and decision trees techniques are applied to analyze and predict the particulate concentrate. The estimation of particulate concentration using Artificial Intelligence will significantly contribute toward the development of quantitative tools to be used in correlating of cause and effect of dust concentration in mines. The results obtained in this work will form a sub-unit of a respiratory health monitoring system for mine workers. The system is essential in the collection, analysis, and tracking of mine workers’ respiratory health, thus it forms part of an early intervention system for mine workers. From the existing theory, we expect the Artificial Neural Network will perform much better than previously used classical models.

Jun 25, 2023

By Brent Duncan, Doug Harding, Bob Stier

The 73rd Street Tunnel Project is part of “The Tunnel and Reservoir Plan” (TARP)also known as the Deep Tunnel Project, and is located in the Village of Bedford Park, County of McCook, State of Illinois. The project consists of a ø 4.42 meter × 2,060 meter long (14´-6? bore, 6,760 foot)tunnel. The completed tunnel is used as a bypass tunnel for the McCook Cup Reservoir Project. The project was awarded to Affholder Inc. of St. Louis, in 2000. The paper describes the project in which a new, high-powered open gripper type main beam machine was used in which high advance rates have been achieved using conventional muck haulage techniques. Features of the project include the installation of rock support consisting of counter-sunk rock bolts that are required to be pull-tested for strength per project specifications. Installation and testing of the bolts are done during the boring cycle. Muck haulage was done by conventional muck car train and hoisting at the construction shaft. As the site layout did not include a tail tunnel, the trains needed to be shuttled at the shaft bottom. Even with the bolting requirements and the muck haulage without a tail tunnel, the Affholder site personnel still achieved high advance rates on the 73rd Street Project.

Jan 1, 2003

By J. F. McDonald

On December 8th of last year, the new St. Clair River tunnel was holed-through to Port Huron, Michigan. The tunnel, commissioned by the Canadian National Railway, was needed to replace an existing tunnel that had been built between 1889 and 1890, and had remained in continuous operation until the new tunnel was opened to traffic in April of this year. The original tunnel, after more than 100 years of service, was still structurally sound, but was too small to accommodate the double stacked container cars and other advances in the railroad's equipment that had developed over the years. Prior to the construction of the first tunnel, all freight was barged across the river. It was a slow, expensive process, which in winter was sometimes impossible. The nineteenth century tunnel was built in twenty months, utilizing two shields that mined to the middle from each end. The lining, which is still in excellent condition, consisted of bolted, cast iron segments, with an O.D. of 6.4 meters. It was the first sub-aqueous tunnel built in North American, and it's use of compressed air under the river and hydraulic power on the shields may also have been firsts. The digging was done by hand, and the muck hauled out by mule drawn wagons. Boulders and methane gas were reported to be a constant problem during the drive, and compressed air sickness was common, but when the two shields came together in August of 1890, it was reported that the alignment was within 6 mm. The new St. Clair River Tunnel was constructed for basically the same reason as the original. The larger equipment which the railroad is using today would not fit through the old tunnel, and once more they were forced to ferry the cars across the river.

Jan 1, 1995

Projections of coal reserves in Central Appalachia are essential for long-term planning in the region. Annual production is declining in some states, such as Virginia, and mineable reserves for the Central Appalachian Coalfield are challenged by difficult geological, mining, and market conditions. In order to project coal mining longevity in this region, interviews with mining companies were conducted to assist in the determination and assessment of technical and economic factors that impact coal seam mineability. This information was applied to seam and coal reserve data developed by state and federal governments. The results were carefully analyzed to determine the effects of various factors on the overall mineable coal reserve base.

Jan 1, 1998

By V. B. Achanti

This paper deals with the effect of various bit geometric parameters on failure characteristics of rock material. Improvement of rock cutting efficiency of continuous mining machines has been an interesting research topic for the last few decades. In the current study, an automated rotary rock cutting simulator, duplicating a continuous miner, was utilized to study these parameters in the laboratory. Improvement of bit performance in terms of its life, cutting efficiency, dust production and energy consumption has drawn wide spread attention over the years. Research shows that optimizing bit parameters can result in efficient fragmentation of rock. Indiana limestone rock material was utilized in this study while bit tip angle, bit tip size, bit spacing, depth of cut and cutting velocity of rotary drum were varied to investigate the failure characteristics. The cutting pressure, penetrating pressure and the depth of cut were monitored on the simulator during the cutting process. Air borne dust and settled dust were measured for each experiment. Then, the specific airborne dust and specific energy were determined for the each type of bit. Triaxial tests were carried out to correlate the failure angle of the rock in static case to dynamic cutting process failure. The physical and mechanical properties of the rock were also determined in order to assess their influence on the wear characteristics of each bit.

Jan 1, 1998

By Suresh P. Babu, Joseph W. Leonard, Richard Muter, D. P. Sen

OUTLOOK FOR COAL UTILIZATION In 1975, about 650 million tons of bituminous coal and lignite mined in the United States was used to meet 55% of the primary energy input for electric power generation and 26% of the total industrial consumption.1 Even though this amounts to only 21% of the total energy requirements, it is believed that with the declining natural gas resources and uncertainty of liquid fuel imports, coal will assume a more dominant role in suppplying our future energy needs. A regional breakdown of the coal reserves of the United States along with their characteristics is shown in Table I. At present the United Stares Energy Research and Development Administration (ERDA) and the US Bureau of Mines (USBM) are financing extensive research programs in advanced mining methods and energy conversion processes. The increased demand for wal which may result from these research programs may also create large-scale environmental protection problems. As more and more coal is mined the production of undesirable coal fines and dust also increases proportionally. The USBM and the Environmental Protection Agency (EPA) research in this field includes development in the areas of instrumentation for qualitative and quantitative analysis of wal dust, protective devices, and dust collectors. Dust control by water sprays, steam, and foam are also being investigated. Other aspects of safety in mining include developing methane drainage techniques prior to coal mining, fire and explosion prevention, and neutralization and disposal of acid mine waters. It is the belief of coal technologists that when the emphasis shifts to coal as the primary source of energy. the existing methods of mining and preparation of coal must be improved considerably to supply large quantities of quality coal for energy conversion. It is the objective of the present large-scale research financed by ERDA to produce substitute fuels from coal. Large-scale gasification pilot plants are being constructed by Bituminous Coal Research, Consolidation Coal Co., Institute of Gas Technology, and the Pittsburgh Energy Research Center to produce coal gas of natural gas standards at 1,000 psig. The processes being adopted by these pilot plants are oriented towards recovering most of the sulfur from coal by absorbing H2S and its subsequent conversion to elemental sulfur. The environmental protection standards will be strictly followed in using the results of these pilot plants to construct large-scale coal gasification plants in the latter part of the 1970's. With the increasing awareness of the need for air pollution control, considerable research is being done to minimize sulfur dioxide emission from thermal power plants. Utilization of limestone and dolomite scrubbing systems and caustic treatment of stack gases have proved to reduce sulfur and nitric oxide emissions by about 90 to 96%.3 Currently, about 22 scrubbers are in use in the United States to reduce sulfur in stack gas emission. In the long-term, it appears that optimal combinations will be developed involving both advanced coal preparation technology and wet scrubbing. The sulfur compounds are converted either to elemental sulfur of sulfuric acid. Besides the sulfur compounds, the major byproduct of the coal utilization industry is the large amount of coal ash. The Coal Research Bureau at West Virginia University has developed a practical use for coal ash as a structural material. The coal industry will undergo revolutionary changes when coal becomes the primary source of energy. New coal mining and preparation processes will be introduced to meet the ever-increasing per capita energy requirements. 2. BENEFICATION Introduction Coal preparation, like the beneficiation of ores, is also aimed at the separation of values from associated waste. Even though the unit operations involved when enriching ores and coal are similar, there are certain characteristics unique to coal preparation. Unlike the scattered and concentrated veins of underground minera1 ores, coal is distributed uniformly and very much in abundance in the coal mines. Coal occurs as the metamorphosed sedimentary deposits of vegetable matter, while metal and mineral deposits occur in great varieties of forms, structures, and origin-from igneous to sedimentary and metamorphic. The mined coal, being much more friable than mineral ores, is subjected to less intensive size reduction operations. Ores are usually ground to a very fine size for subsequent concentration, while coal is crushed to a coarser size, since considerably less liberation is needed to achieve the desired degree of separation. Since mineral matter is to a great extent discretely distributed in coal, concentration is mainly achieved by taking advantage of differences in specific gravity between clean coal and associated waste. In general, about 90% of coal is concentrated using specific gravity separation and about 10% by froth flotation. In contrast, these operations are frequently reversed in the beneficiation of ores. In coal preparation almost all fractions separated during various stages are made use of. while large amounts of gangue material are rejected in the concentration of ores. Hence, coal generally has a much lower ratio of concentration than ores. Since ore deposits are frequently more variable and mineralogically complex than coal, beneficiation of ore may require more plant flexibility and point-to-point quality control. This characteristic difference between the mineral ores and coal is attributed to the generally used one-step processing in coal as compared to the multiple-step processing of ores. Dewatering to enhance the energy content of coal is usually considered a major unit operation. Even though thickening and filtration are common for dewatering ore concentrates and cleaned coal, vibrating centrifuges and disk filters find unique application in the coal industry for achieving these types of solid-fluid separation. In coal preparation, thermal drying is carried out in separate units at the mine. While ore concentrates are usually dried at the smelter. Although the drying of ores is seldom considered dangerous, volatile matter and combustible dust are reasons why the thermal drying of coal can be hazardous. Open air storage of ores and mined coal results in partial oxidation. Unlike the oxidation of ores, the oxidation of the pyritic and carbonaceous constituents of coal together with the heat of condensation of moisture contribute to spontaneous heating and the subsequent combustion of coal in storage. Among the other significant difference between concentration of ores and coal are the weight and capacity of processing equipment. Coal processing employs less cumbersome, higher capacity units while the beneficiation of ores usually requires much more massive and frequently lower capacity equipment. Properties of Coal Which Influence Design The widely varying and heterogeneous composition of coal, due to metamorphism, determines the preparation design and uses of the resulting products. Petrography serves as a useful system of classification to identify the coal types present and their distribution. Early

Jan 1, 1985

By Jean E. Tilden

An investigation of several trace elements distributed among sulfide minerals from deposits located in the southeastern United States was conducted. The deposits investigated are distributed within both the Blue Ridge Province and the Piedmont Province, which are contiguous geographic provinces. Twenty five deposits were examined;' eleven in the Blue Ridge Province and fourteen in the Piedmont Province. Figure 1 shows the locations of deposits investigated. In the deposits investigated, the mineral phases examined were pyrite, pyrrhotite, chalcopyrite, and sphalerite. These phases were chosen because of their relatively widespread occurrence, although no pyrrhotite was seen in the Piedmont Province. A total of 116 polished surfaces of ores were prepared, and mineral phases were collected from these surfaces for analysis. Samples were analyzed for cobalt, nickel, manganese, lead, tin, chromium, molybdenum, and gold. A total of 372 analyses were made. Trace elements were determined by atomic absorption spectrophotometry following standard procedures. In this study, trace elements are defined as those elements which are present in the mineral but which do not affect the chemical formula for that mineral. Lead is considered as a trace element only in ores where little or no lead sulfide could be identified as a distinct mineral phase.

Jan 1, 1972

By L. Meier, M. Dennis, J. Schieffer, K. Murray

"INTRODUCTION Contrary to popular belief, Arizona State Trust land is not public land. All uses of the land must benefit the Trust, a fact that is considered with the review of each application received for sale, lease, or permit. This includes applications for activities ranging from commercial development to recreation. In 1863, the Territory of Arizona was established by an act of Congress. This act reserved sections 16 and 36 in each township to be held in trust for the benefit of the common schools. Later, the Enabling Act of 1910 allowed the Territory of Arizona to prepare for statehood. This act reserved the additional sections 2 and 32 of each township for the common schools and granted another 2,350,000 acres to be held in trust for other beneficiaries. In all, Congress granted the State of Arizona almost 11 million acres. The State was to manage those lands and maximize revenue for 13 separate beneficiaries. To meet this mandate, the State established the Arizona State Land Department (ASLD) in 1915. During fiscal year 2015, the ASLD contributed $136 million to the permanent fund, bringing the total value to over $5.1 billion, through the sale and leasing of the land and natural products which includes minerals. The current inventory of State Trust lands includes 9.2 million acres representing about 12.7% of the State.The ASLD Minerals Section manages the exploration, development, and leasing of mineral products on State Trust land. We are not a regulatory agency, but a department guided by our fiduciary responsibilities to the Trust. Our mineral programs include: Exploration Permits, Mineral Leases, Mineral Material Leases, Geothermal Leases, Oil & Gas Leases, and Special Land Use Permits. INDUSTRIAL MINERALS ON ARIZONA STATE TRUST LAND Industrial minerals fall under the category of either Mineral or Mineral Materials Leases. Common industrial minerals found on Arizona State Trust land include potash, limestone, gypsum, salt, specialty clays, zeolites, crushed stone, and sand and gravel."

Jan 1, 2016

By S. Constantinescu

The alloys mainly used for short (or segmented) chip material cutting (cast iron, porcelain, etc) are alloys of the WC-Co type; in some cases with small additions of other carbons. The same alloys but of different granulometric classes are also used for pieces exposed to wear (wire drawing, moulds) The higher performance of the WC-Co alloys in chip machining applications is accounted for by their very good heat conductivity, which is 2-3 times higher than that of fast steels. The hard-alloys producers can resort to a wide range of possibilities to achieve variation of properties of a WC-Co composition and thus they can adapt their products to the particular type of tools they may choose to manufacture. The present metallography technique allows for a correct identification and evaluation of hard sintered carbons structures. The metallography approach is an indispensable method of investigation and control in the industry.

Jan 1, 2008

By T. M. Gurr

Large quantities of phosphate rock are mined and processed in Central Florida (Figure 1). The phosphate rock from the mines is further processed in "chemical plants" to produce phosphoric acid (Figure 2). A by-product of the processing' of the phosphate rock to produce fertilizer chemicals is an impure form of gypsum referred to as phosphogypsum. For each ton of phosphate rock processed, approximately 1.5 tons of phosphogypsum is produced (Figure 3). The typical method to dispose of this by-product gypsum is to stack it in large piles, locally referred to as gypsum stacks or gypsum fields (Figure 4). These gypsum stacks have been the focus of many studies in recent years in an attempt to identify the potential for ground water and/or air pollution associated with the stacks. This paper attempts to discuss some of the ground water impacts and current attempts to minimize these impacts.

Jan 1, 1990

By Yubo Tu, Lianqi Wei, Tianyi Zhao, Peiwei Han, Zhengchen Li, Shufeng Ye

The effect of oxygen partial pressure on the volatilization percentages of valuable metals from iron-rich pyrite cinder by chlorination-volatilization method using CaCl2 as chlorinating agent was investigated in this study. The volatile products were collected directly and analyzed by X-ray diffraction. It was found that there were CuCl2, CuCl, PbCl2, and ZnCl2 existed in the volatile products. Au and Pb volatilization percentages were almost not affected by oxygen partial pressure. Both Cu and Zn volatilization percentages were negatively correlated with oxygen partial pressure when CaCl2 dosage was no more than 4 wt%, and almost uncorrelated with oxygen partial pressure with a CaCl2 dosage of 6 wt%.

Dec 19, 2023

By E. W. Sawyer

Attapulgite is a magnesium aluminosilicate clay mineral which exhibits unique, processing-enhanceable physical and chemical properties that are related to its current commercial uses. Properties of commercial interest are gelling, absorption, adsorption, binding, acid neutralization and many others. Major industrial applications are: (1) absorption by heat treated grades utilized in industrial oil and grease absorbents and in agricultural pesticide carriers; (2) gelling of aqueous liquid products by colloidal grades for stabilization and viscosity control in salt water drilling fluids, suspension fertilizers, liquid animal feed supplements, paints and tape joint compounds; (3) adsorption by heat treated varieties for the removal of catalysts, color bodies and other polar compounds from hydrocarbon streams; (4) gelling of organic liquids by colloidal attapulgite/surfactant blends in oil-type paints, fibrated and nonfibrated asphaltic coatings and mastic compositions, and (5) the binding of feeds and molecular sieve sorpents with colloidal type attapulgite products. These applications and other less common uses and potential uses will be discussed along with, the necessary selective mining and plant processing features related to each property and application.

Jan 1, 1986

By J. Partyka, J. S. Stachulak

Dust produced during blasting in a copper/nickel based mine was studied and characterized. A stope utilizing the crater blasting technique, or the vertical retreat mining (VRM method), was examined. Two dust monitors were used to measure an airborne dust produced during blasting operations. The data collected in situ was primarily used to formulate the boundary value problem for a generalized equation that describes the transportation process of airborne dust from all places where dust is produced by the VRM mining method. The field data was also used to define the analytical forms for the initial and boundary conditions, to provide a simple and reliable equation for flow of dust in a stope vicinity, and to identify the non-measurable constants. The effects of the amount of blasting material and of the ventilation system in use on dust concentration are also discussed.

Jan 1, 1995

By Evangelos Spyridonos, Thomas Frommer, Wolfdietrich Skala, René Prissang

Operational grade modelling is a technique that uses production data to run daily updates of property models. It will enable mining engineers to use property predictions based on the most recently acquired data as support for quality control and decision making. The approach necessitates that the properties of the run- of-mine material can always be attributed to individual mining blocks or charges. The software employed must be highly reliable, because a system failure or the loss of data could seriously affect the mine's quality management. An operational grade modelling system has been developed for the Breitenau magnesite mine. It makes use of the Linear Octree Based Property Modelling system which was conceived and realised at the Free University of Berlin. This paper describes the system design and gives an account of the experiences during the first six months since system start-up.

Jan 1, 1996