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By Sandip K. Mukherjee

In underground mining operations, ventilation and water sprays are the common methods of controlling dust. In recent years there has been a proliferation of technical literature dealing with water sprays for dust control. However, guidelines for the design of an effective water spray system have not been presented to the mining industry. This paper reviews developments in water spray dust control technology and recommends guidelines for water spray systems to control dust in under- ground coal and non-coal mining operations. These guidelines suggest type, number, location and orientation of nozzles, desirable operating water pressure, and associated filtration system.

Jan 1, 1983

By J. H. Canterford

To date, large-scale solution mining has received little attention in Australia, although the potential of this technique has not gone unnoticed. The possibility of long-term damage to the local environment has also been recognized. Because no two orebodies are the same, it is clear that the application of solution mining techniques and the assessment of environ- mental damage will be somewhat different for different orebodies, even though the general principles will be the same. At present the most significant copper solution mining operation in Australia is at the Mammoth (Gun- powder) Mine in northern Queensland. This mine currently produces more than 3 000 t of cement copper a year.1

Jan 1, 1981

"In this review, the sintering process is first described and analyzed to identify the key factors affecting the structure and quality of iron ore sinter. Under fixed sintering conditions, the granulation efficiency, nucleus stability and primary sinter melt volume and properties of the iron ore are considered to have significant influence on the sinter structure and quality. Discussion is then focused on the effects of the chemical, physical and mineralogical characteristics of the iron ore on these key factors, and the consequences for sinter quality.IntroductionSintering is the most economic and widely used agglomeration process to prepare iron ore fines for blastfurnace use. In modern blast furnaces, particularly in East Asia, iron ore sinter typically constitutes more than 70% of blast-furnace ferrous feed. High sinter quality and efficient sinter production are thus required both to withstand extreme operating conditions and maintain the productivity of modern blast furnaces. At the same time, due to the increasing depletion of high-grade iron ore resources from large deposits, iron ore producers are moving toward developing an increasing number of deposits of much smaller sizes to maintain current production levels. It is therefore imperative for iron ore producers to develop long-term strategies to maintain the quality and consistency of the iron ore fines they are producing while exploiting these smaller, complex deposits. The iron grade, gangue minerals present, overall mineralogy as well as physical characteristics of iron ore fines being mined from these different deposits vary considerably. Overall, ores now have highly complex mineralogy, are becoming more porous and friable, and contain increasing amounts of gangue minerals, which will have important implications for the sintering process and sinter quality.Blending is one of the most effective options being explored by iron ore producers to deal with multiple small complex deposits. This allows the iron ore producers to reduce the number of products and take full advantage of the unique characteristics of each individual deposit to achieve long-term product consistency while increasing production. Blending is also a common practice in sinter plants as it is almost impossible to produce from one single ore a high-performance sinter mixture with the required processing characteristics. A typical sinter mixture used in Japanese steel mills (Nakano and Okazaki, 2007; Matsumura et al., 2013) often contains five or more ores to achieve balanced sinter quality and productivity with relatively low cost of raw materials."

Jan 1, 2015

By A. Venkatachalam

Spinel ferrites, like NiFe2-2x Znx Ti4 O4 Fe CO1.5 Ge0.5 Tix O4, Ga1-x Fex Ni CO O4, Nil-x Fex Mn2 O4 have been prepared using the respective metal oxides in Stoichiometric quantities, by the ceramic method. The oxides were homogenized in acetone medium, pelletifed by using poly vinyl acetate as the binder. They were fired at 1000°C for 100 hours for compound formation. Chalcogenide spinels such as Zn1-x Cux Cr2 Se4 where 0=x=l and Cu1-x Fex Cr2 Se4 where 0=x=0.3 have been prepared by using 99.99% pure elements and then fired at 1000°C in quartz ampoules under vacuum conditions. X-ray diffraction studies of these compounds indicated a single cubic spinel phase. DC resistivity studies of the compounds were taken between 300-700K using LCR bridge by two probe technique. Thermo-electric power measurements were taken between 300-500K for all the compounds. Initial susceptibility studies have been carried out using a low field (0.506) and from which the nature of magnetic dimains and Curie temperatures were determined. Magnetic hysteresis measurements were carried out at 300K and at 80K, using alternating current hysteresis loop tracer, at 2K02 field. Mossbauer spectral measurements were carried out using Co57 source embedded in a copper matrix and an absorber containing 0.3 mg/cm2 of the sample. The spectra has been fitted by Mossfit Program. The catalytic effect of the spinel ferrites NiFe2-2x Znx Tix O4 where 0=x=1 has been studied by using the model reaction of decomposition of H2O2 at temperatures from 40°C to 70°C. It was found that the spinel oxides were found to possess poor catalytic activity.

Jan 1, 1990

By J. J. Poveromo

"Iron ore for alternate iron processes concerns alternate iron products designed for use in EAF (electric arc furnace) steelmaking processes. These alternate iron products include both DRI (direct reduced iron), HBI (hot briquetted iron) and merchant pig iron. Merchant pig iron can be produced in conventional blast furnaces, mini blast furnaces (including charcoal BF's) or novel processes such as RHF/SAF (rotary hearth furnace/submerged arc furnace) such as Iron Dynamics or RHF such as Mesabi Nugget. These novel processes are coal based and can use iron ore concentrates or recycled steel plant oxides. The blast furnace processes can use conventional feed materials: pellets, sinter, lump ore and coke. However, DRI and HBI processes are predominantly pellet based but require DR grade pellets that are low enough in acidic gangue (SiO2 and Al2O3) to avoid additional expense in the EAF process This paper will focus on the quality and availability of DR grade pellets for NAFTA DRI/HBI plants but also concentrates for fines based processes and feed materials for merchant pig iron production. INTRODUCTION This paper will outline alternative (to the blast furnace) competitive ironmaking processes and process routes. Within each section the types of iron ore to be utilized will be discussed. Before discussing some of the details of these processes, it may be appropriate to review some definitions and commonly used terms within this industry. DefinitionsDirect Reduction: Reduce iron oxide to metallic iron without melting. Unreduced ore compounds remain as undesirable oxides • Direct Reduced Iron: Iron oxide feedstock exits in same form as entered (pellets in, pellets out; lumps in, lumps out) • Hot Briquetted Iron: DRI that has been hot (1200°F, 650°C) briquetted to a high density pillow shaped briquette • Hot Metal: Molten iron in liquid form, above 2500°F, 1370°C • Pig Iron: Solid product of the iron blast furnace • Residuals: Undesirable elements such as copper, nickel, chromium, tin, sulfur, molybdenum and phosphorus • Gangue: Rock minerals in the iron ore such as silica (SiO2), alumina (A2O3), calcia (CaO), magnesia (MgO). These remain in the oxide form in DR processes. • Reduction: Fe2O3 + 3 CO = 2 Fe + 3CO2 2 Fe2O3 + 3 H2 = 2 Fe + 3H2O (Fe2O3 > Fe3O4 > FeO > Fe)"

Jan 1, 2018

By D. J. Collins

While the charcoal in pulp (CIP) process was introduced to the mining industry many years earlier, it did not gain widespread recognition until 1973 when Homes take Mining Company installed a CIP circuit at their Lead, South Dakota plant. Since then, a number of mills have been put into production which utilizes activated charcoal for the recovery of precious metals. One of these plants was the Jerritt Canyon mill which Freeport Gold Company commissioned in 1981. It was during the time that the author was employed by Freeport Gold Company that the ideas and concepts presented in this paper were formulated.

Jan 1, 1989

By A. R. Laplante

The mineralogy of the Joe Mann mine differs from that of other deposits of the Chibougamau area that are exploited by Les Nines Camchib Inc. It is characterized by very fine first generation gold and very coarse second generation electrum. Successful processing required adjustments of the processing flowsheet, which includes gravity, flotation, and cyanidation. A study of coarse gold liberation in the gravity/grinding circuit is described. Modifications to the flotation circuit and the reconditioning of a small capacity cyanidation circuit are presented.

Jan 1, 1989

By Elwyn H. King, Thomas R. Kuesel

I. CONCEPT MARTA's Peachtree Center Station is being mined out of hard rock, directly beneath Atlanta's central business district, with minimal surface disruption during construction. Its cost is competitive with that of a conventional cut-and-cover alternative owing to its design concept, which utilizes the rock as a primary structural and architectural material. II. PLANNING The station was originally planned for cut-and-cover construction. However, Peachtree Street is unusually narrow for a main business street (generally 78 feet (24 m) between building lines) and cut-and-cover construction would therefore be very disruptive to surface traffic and severely restrict access to adjacent buildings, including Peachtree Center, Atlanta's showcase business/commercial complex. (See Fig. 1.) Tunneling had been considered, but was initially thought [ ]

Jan 1, 1979

By Gilles Recher, Jörg Riechers, Albert Lueghamer

"INTRODUCTIONIn view of a global trend towards urbanization, more and more trunk sewers and combined sewer overflow tunnels (CSO) with medium to large diameters and the corresponding link sewers are currently built and under design. Shielded tunnel boring machines using segmental lining as tunnel support represent an efficient solution for construction of new wastewater and supply tunnels. Especially in the field of sewers, the durability of concrete structures both exposed to any groundwater present on its exterior and to aggressive waste water as well as gases on its interior is a key requirement. Despite thorough research on segmental lining and mechanized tunneling machinery, conventional thermoplastic liners show comparatively minimal progress in terms of practical advancements. This is in contrast with the development of the latest segment embedded high density polyethylene (HDPE) system. Based on experiences achieved, this paper discusses the latest development of an integral protective lining system in respect of material characteristics and its adaptability to both project and customers’ demands. Reviewed performances, as the bondage behavior of the embedded HDPE system at axial stress loads due to acting thrust cylinders during ring build as well as the ability to drain pressurized water behind the embedded membrane, tested at full scale segments, are also presented. The paper is round off by presenting first details of sewer projects endeavoring to utilize this cutting-edge solution for an integral concrete protection, which will be commenced beginning of 2016.CASE HISTORIES ENCOURAGE ADVANCEMENTS Past experience has shown that unprotected concrete surfaces as well as chemical based linings such as coatings, sprayed linings and cured in-place-systems cannot reach the desired life times. Also the fact that in deep tunnel sewer system hardly maintenance is possible, a durable and maintenance free system is required which only can be reached by applying mechanical anchored HDPE (CPL)."

Jan 1, 2016

By K. V. K. Prasad

Forecasting mined grade variability from exploration information is a challenging task in mine planning. For effective planning of activities such as workplace scheduling, ore grade quality control etc. development of realistic numerical/simulation models of in-situ variability from exploration information is an essential first step. Geostatistical conditional simulation (GCS) is one of the well known methods to develop these simulations. Recently, stochastic fractal models based on the assumptions of scale-in variance and self-similarity have been used for developing simulations of several natural phenomena. It has been suggested that these models might permit generation of short-scale variability information from exploration data with greater fidelity when the data satisfies the attendant assumptions. In this paper the stochastic fractal models are reviewed and their relationship to geostatistical variogram models is examined. A comparison of the two simulation techniques has been per-formed using coal sulfur data from a mined out coal property. The results of this comparative analysis are also presented in the paper.

Jan 1, 1992

By Daniel W. Kappes

The 1.8 million tonne Itos tailings deposit is the result of sever­al years of processing by Comibol of the San Jose and ltos Mine ores at Oruro Bolivia. The historic flowsheet consisted of a flotation circuit in which silver-bearing galena and stibnite were concentrated. Approximately half the silver in the ore was not recovered, and the existing tailings contain slightly over 200 grams silver per tonne, in the form of complex sulfides of silver, antimony, lead, and other metals coating grains of pyrite. An extensive laboratory program was conducted to exam­ine conventional processing l)lethods such as cyanide leaching and regrinding followed by flotation. However, the silver-bear­ing sulfides are in intimate contact with the pyrite and the pyrite comprises 30% of the total tailings weight. Cyanide leaching recovers only 40% of the silver and the cyanide consumption is uneconomically high. Flotation produces an upgraded, but still uneconomic, concentrate. For this reason, chloride leaching had been evaluated by Comibol, and in the mid 1980's Comibol undertook an innova­tive test consisting of two 300 tonne field heap leaches using a cold chloride solution. The tests were partially successful, but could not be applied to the bulk of the tailings which are already ground to 50% minus 200 mesh. In 1992, Kappes, Cassiday & Associates undertook to develop a hot agitated chloride leach flowsheet, and is current­ly constructing a treatment plant under a turnkey contract from a Bolivian company, Baremsa, S.A. Using this process, 85% of the remaining silver can be recovered, with significant by-prod­uct credits from antimony and lead. The project features hot, agitated acidic chloride leaching, filtration, crystallization of lead chloride, and precipitation of metals using iron scrap. Arsenic is removed from the precipitate by caustic leaching, and minor metals by furnace refining. Antimony is recovered as the oxide by cupelation, and silver is poured as <lore from the cupel. Production rate will be 600 tonnes per day. Startup is scheduled for late 1995.

Jan 1, 1996

By H. Maleki

This paper recognizes the 100th year of research accomplishments by the mining industry resulting from close cooperation among mining companies, geotechnical consultants and researchers from the former United States Bureau of Mines in stability assessments and development of improved and productive mine designs. The paper provides an overview of dramatic developments in geotechnical instrumentation, and its applications in the U.S. and around the world for enhancing the understanding of ground response to mining-induced changes in stress, resulting in improvements in ground control technologies.

Jan 1, 2010

By E. Kurt

The field of percussion rock drilling is subdivided into two areas of application; that which takes place on the surface and that which takes place underground. Surface drills are used in quarrying, highway construction, and maintenance work; underground equipment in mining and tunneling work. Two basic principles are involved in the operation of all percussion drills. First, the principle that reciprocates the impacting piston and second, the principle that causes the drill steel and bit to rotate. The back and forth motion of the piston is accomplished by a self-acting automatic valve that admits air alternately to each end of the piston (Figure 1). Drill steel and bit rotation is imparted by an integral ratchet mechanism (Figure 2) in the so-called "rifle bar" machines (Figure 1) or by a separate pneumatic motor in "independent rotation" drills (Figure 3). While rock drills are subject to all kinds of physical and operational abuse, they are most sensitive to faulty lubrication. Proper lubrication is the single most important factor in the longevity of a percussion drill.

Jan 1, 1970

By R. F. Korcak

There exists a wide array of industrial by-products that can be shown to produce beneficial responses in the soil/plant environment. These materials range from clean coal technology residues produced in the generation of electric power, particularly those high in gypsum, to mineral &apos;fines&apos; produced by the aggregates and crushed stone industries. A number of these materials will be examined in relation to potential nutritional interactions in soils and crops with emphasis on trace elements. The significance of utilizing these materials in agriculture as a component of sustainable agricultural systems will be discussed.

Jan 1, 1995

By Panshi Xie, Yan Chen, Shaogang Wu, Yang Hang

In order to realize the intelligent mining of coal seam with large dip Angle, this paper adopts the methods of large proportion variable Angle loading threedimensional physical simulation experiment, numerical simulation and field measurement with digital twin technology. The hydraulic support with large dip Angle and large mining height is used as the prototype to design the physical entity model of 1:5 hydraulic support, combined with modeling and graphics rendering technology. Angle, displacement and load sensors were selected and placed to realize the data channel between the lower machine and the upper computer of the digital twin system, so that the position and load data of the physical entity model and the twin model of the laboratory hydraulic support could be shared in real time. Moreover, the multi-dimensional dynamic and static load transfer law and the position evolution characteristics of the support and surrounding rock under different inclination angles were analyzed. The results show that: with the increase of the Angle of the working face, first, the initial support force required by the support decreases, and the damage degree of the roof increases; When the roof is soft, the lifting operation can avoid the instability of the support to a certain extent. Second, under the action of positive pressure, the load of the top beam under different angles is balanced; Under the backpushing action, the load in the upper inclined area of the shield beam increases gradually, while the load in the lower inclined area decreases gradually. Under the lateral push, the load changes periodically, and the load in each cycle is increased compared with that in the previous cycle. Third, the numerical simulation analysis shows that the load on the lower bracket is less than that on the upper bracket, and the load on the bottom of all the columns is greater than that on the middle and upper brackets. In order to reduce the impact of the columns on the bottom plate or the base, it is necessary to improve the anti-subsidence ability of the base. Finally, according to the research results, the improvement and optimization measures of the support are put forward, and the field test shows that these measures effectively solve the problems of sinking, sliding and tipping of the support in the working face with large inclination Angle, and obtain good application results.

Feb 1, 2024

By Madan M. Singh

Increasingly, geotechnical data are being collected for various types of coal development projects. In many cases, a specific design concern is addressed. However, many data collection programs are not intended to immediately support mine design activities or to resolve a specific concern. The following discussion describes some current geotechnical approaches in mine planning, development of reserves, and peripheral activities. Types of Data Collection Programs Geotechnical data collection is increasingly becoming a part of standard coal exploration programs, performed along with stratigraphic evaluations and coal quality tests. The aims of such programs vary. The purpose of the exploration may be to fill out the portfolio on a block of reserves that is to be sold, leased, or held for potential future development. In such a case, a generic suite of geotechnical data are collected. The resulting engineering reports may touch on the more well known mining problems of the area, but detail may be lacking. The geotechnical data are mostly intended to enhance the saleability of the package. Mine design alternatives are generally not addressed.

Jan 1, 1985

By Greg Sanders, Bill Lueck, Michael Gilbert, Mahmood Khwaja

"The city of Minneapolis contracted with CDM Smith to update and provide a conceptual design for improvements to mitigate surcharge flooding in the Central City Storm Water Tunnel System (CCSTS). As a part of the project, CDM Smith conducted a field survey and condition assessment of the existing tunnel system. Information from the survey was then used to update the existing XPSWMM model and develop system wide alternatives.The CCSTS provides storm-water runoff drainage for nearly the entire area of the city’s downtown commercial district. The system consists of deep storm-water tunnels constructed in the St. Peter Sandstone, approximately 21 m (70 ft) below the street’s surface. The primary tunnels comprising the Central City storm water tunnel system are located below Hennepin Avenue, Nicollet Mall, Lesalle Avenue, Marquette Avenue South, 2nd Avenue South, South 5th Street, Washington Avenue South, Portland Avenue South, 2nd Street South, and Chicago Avenue South, as shown in Fig. 1. This network of tunnels conveys the runoff from a 305-acre tributary area that is generally bound by Hennepin Avenue and 1st Avenue North to the east, 12th Street to the south, 4th Avenue South and 7th Avenue South to the west, and 2nd Street South. These tunnels were constructed between 1936 and 1940, except for the Marquette Avenue South tunnel, which was constructed between 1963 and 1964.The CCSTS operates as a gravity flow system. These tunnels were constructed within the St. Peter Sandstone layer of bedrock and emerge from the bedrock at the Mississippi River below St. Anthony Falls. The Central City and the adjacent Chicago Avenue tunnel system converge into a single outfall at the Mississippi River. The runoff discharges from the converged outfall to a side channel of the Mississippi River, called a tailrace, located near the Guthrie Theater. The Minneapolis Division of Surface Water and Sewers provided 32 historic plats detailing the plan and profile of the tunnel system.The tunnel plans show nine different cross-section configurations. Eight configurations within the overall system generally show the same geometric “cathedral” shape with the inside dimensions varying from 1.2 to 1.8 m (4 to 6 ft) in width and 1.8 to 2.4 m (6 to 8 ft) in height. For analysis, these eight configurations were reduced to three configurations with regards to tunnel liner, cross-sectional area and support. For simplicity, the three configurations are described according to the three types of tunnel support used during construction: none required, light timber and heavy timber"

Jun 1, 2019

By S. B. Bhagwat

The United States has abundant coal resources that could last at least another century. and probably longer at present consumption rates. Geographically, the coal resources are distributed over the entire nation including Alaska, although there are no coal deposits in the highly populated areas on the two coasts. This allows free access to the coal, but makes transportation more expensive. Not all coals can be utilized equally because they differ vastly in quality. The sulfur content of coals, considered as the most detrimental acid rain-causing element, varies from as low as 0.3 percent in some areas of the western U.S. to 5 percent or more in parts of the Midwest. The chlorine content, which causes corrosion of plant hardware, also varies regionally. The 1990 amendments of the Clean Air Act of 1963 (CAA) require that emissions of sulfur be restricted and rolled back in two stages by the year 2000. There have been a number of reports expressing concern about the future of the industry in the states where high sulfur coal is produced. The remedies devised by the federal government and many coal-producing states in the past to "se-cure" the future of the regional coal industries have focused on the physical task of removing sulfur rather than the economic challenge of doing so at a cost that will enable high-sulfur coals to survive and compete. The past remedies, generally, were not specific enough to account for the characteristics of regional coal deposits and did not look at the coal market as an integrated national and international entity. The State of Illinois has, in recent years, taken a more comprehensive approach to the solution of the problem.

Jan 1, 1992

By S. A. Jeric

In-pit crushing and conveying of waste has been utilized in the mining industry for over 30 years. In recent years, innovations in crushing, conveying, and particularly waste and leach stacking technology have sparked a renewed interest in continuous haulage systems for large-scale open pit applications. A review of the advantages/disadvantages and operating techniques of crushers, feeders, conveyors, and stacking systems currently available is made. The paper examines some operations that are currently using large scale continuous haulage systems. Finally, a case study is presented that evaluates the application of a continuous waste haulage system in a large open pit mine in the Western United States, The case study includes a economic comparison with the existing truck haulage system.

Jan 1, 1997

By D. M. Ziebarth

"During the mid to late 1960’s, the underground potash industry in Saskatchewan was born. For the next four decades the industry operated at a steady pace supporting a large part of the world demand; until 2008 when the potash market heightened. Operators were motivated to capitalize on this increased demand, new mines were proposed while existing mines were planning upgrades. Potash Corporation of Saskatchewan (PCS) was one of the major producers planning upgrades to their production facilities quickly, including modifying the existing headframe and shaft at the PCS Cory Site to accommodate a new 1500 tonne per hour hoisting plant. Upon completion of the project, the innovative operations group continuously reviewed methods to increase production and reduce operating costs, allowing PCS to continue being competitive on the world market. This paper will describe the design challenges encountered during the development of the infrastructure around an operating facility whilst minimizing down time, schedule, capital and construction costs. This paper will also explore the strategy to increase capacity of the newly commissioned hoisting plant. BACKGROUND Potash production is a major Saskatchewan industry, and has played a significant role in the economy for over 40 years. Production commenced in 1962 when water problems were overcome at the International Minerals and Chemical (IMC) mine near Esterhazy, Saskatchewan. A surge of development by other companies resulted in twelve companies opening ten mines by 1970. In 1975 Potash Corporation of Saskatchewan was created by the government of Saskatchewan and shortly thereafter purchased several mines in Saskatchewan, including the Cory Mine (Cory), near Saskatoon. Cory has been in operation since 1968 and is located 12 km (7.5 mi) west of Saskatoon in central Saskatchewan. The mine is located in the center of the world’s largest potash deposit, 1,000 m (3300 feet) below surface. PCS has embarked on sizable capital expansions of more than CDN $7 billion. The Cory CDN $1.6 billion expansion was expected to raise operational capability of the site to 2.7 million tonnes per year, an increase of 1.9 million tonnes per year (MTPY). To achieve 2.7 MTPY of finished product and considering the 22.6% average production recovery1, 12 MTPY of ore must be hoisted to surface for processing. To deliver this rate required upgrading of the hoisting plant to 1500 tonne per hour (TPH). To accomplish this ambitious challenge, creative thinking, careful planning and a cohesive team was needed to work together to ensure the schedule, budget and most importantly the work was completed safely"

Jan 1, 2017