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By Jay Jones, William D. Rech

The Henderson Mine developed a water treatment system in 1985 to meet the NPDES requirements for its mine water discharge. Unacceptable levels of Zinc and Manganese formed the basis for the design and operation of the treatment system. Since initial start up, this system has reliably removed metals from the mine water and facilitated low cost compliance with water standards. The potential addition of a bio- monitoring requirement to the NPDES Permit in 1990 has added a second dimension to the metals removal process. This paper will review the history of Henderson's success at developing a low capital treatment system for metals removal and the anticipated effects of bio-monitoring upon this system based upon preliminary bio-monitoring screening.

Jan 1, 1991

By Gregory A. Hahn

Explorationists and engineers rarely speak the same language. Explorationists are not cognizant of the information that engineers require to make the appropriate choices and decisions. Engineers can- not "translate"geo1ogic parlance and data into information relevant to proper decision making. This often creates a physical and intellectual "rift" between engineers and geologists that inhibits a smooth transition to development. A transition team leader who is grounded in both disciplines can best facilitate integration and communications between the explorationists, who understand the intrinsic attributes of a given deposit, and the engineers, who have to design for extraction and beneficiation of an orebody.

Jan 1, 2001

By D. A. Augenstein

Operators of coal preparation plants use equipment such as large-capacity dump trucks and bulldozers to haul, spread and compact refuse material to conform to federal and state regulations governing the disposal of solid waste. For example, federal regulations require that refuse be spread and compacted in layers not more than two feet thick. If the refuse layers or piles have poor load-bearing characteristics, movement of equipment over them becomes extremely difficult. The increasing cost and limited space for the construction of settling ponds extensively used for fine refuse disposal are leading to the growing practice of dewatering the fine refuse by means of vacuum disc filters and combining the resulting filter cake with coarse refuse for waste bank disposal. However, this filter cake usually contains more than 25% moisture. Therefore, when it is combined with coarse refuse, the moisture level of the total refuse may become high enough to impair the load-bearing strength of the refuse. Precisely this problem and the attendant difficulties of moving heavy equipment arose when vacuum disc filters were installed at a preparation plant in West Virginia. Combining the moist filter cake with the coarse refuse generally results in a 12% moisture level for the total refuse at this plant. At this moisture level, the refuse can still be handled with some difficulty by the equipment. However, the problem has frequently been compouned after rains.

Jan 1, 1977

By Andrew Thomson, Peter Wright

"A section of a London Underground expanded segmental lined tunnel constructed in the 1970’s progressively deteriorated after 2001, with extensive radial joint spalling and mid-segment cracking. As part of the PPP contract Tube Lines Ltd and their partners carried out various analyses of the tunnel, including analysis of laser scans of the tunnel, geotechnical testing through the tunnel walls, geotechnical desk studies, real-time monitoring and even full-scale segment testing. This paper discusses the behaviour of the tunnel lining in this setting, the causes of failure and the lessons that can be learnt from this rare example of a tunnel which was progressively failing in service. It is finally noted that a replacement tunnel lining was installed during night-time possessions and completed in 2015. INTRODUCTION In 2003, Tube Lines Ltd. was established under a Public-Private Partnership (PPP) scheme to provide maintenance services and upgrade projects for London Underground (LU). The Deep Tube Tunnel Knowledge and Inspection Programme comprised the assessment of all tunnels, shafts and other underground structures. This included a number of lengths of tunnel constructed using segmental concrete linings. First used by LU in the 1960s, the savings both in cost and speed of construction led to concrete linings replacing cast iron for new tunnel construction in all but a few cases. During the initial scoping phase of this programme, inspections identified potential issues with the expanded concrete segmental linings on the Jubilee line. The inspections found a number of segments with surface spalling (Figure 1a), which did not appear on the post-construction defect records. These were generally relatively shallow, up to 40mm deep, spread over a wide area of segment. These were different to spalls caused by handling damage, which are typically localised at segment corners. Subsequent inspections over the following years identified an increasing number of segments with these types of spalls as well as an increased incidence of longitudinal mid-segment cracking (Figure 1b). The increasing occurrence of these defects was hypothesised to be caused by tensile stresses developing in the vicinity of the joint."

Jan 1, 2016

By P. G. Dempsey, J. R. Heberger, J. P. Pollard

During a mine disaster or emergency, underground air can quickly become contaminated. In these circumstances, all underground mine workers are taught to don breathable air supply units at the first sign of an emergency. However, no contemporary oxygen consumption data is available for the purposes of designing breathing air supply equipment specifically for mine escape. Further, it would be useful to quantify the oxygen requirements of breathing air supply users for various escape scenarios. To address this need, 14 participants crawled a distance of 305 m each while their breath-by-breath oxygen consumption measurements were taken. Using these data, linear regression models were developed to determine peak and average oxygen consumption rates as well as total oxygen consumption. These models can be used by manufacturers of breathing air supply equipment to aid in the design of devices that would be capable of producing sufficient on-demand oxygen to allow miners to perform self-escape.

Jan 1, 2015

By Sertaç Dündar, Bilgehan Kekeç, Arif Emre Dursun, Niyazi Bilim

"Estimation of rock drillability is vital for mining and boring operations. For this purpose, many researchers have developed various models and equations to estimate rock drillability. Most of these models aim to determine the drillability of rock and the penetration rate by using the physical and mechanical properties of rocks. Although drillability primarily depends on rock properties, other parameters have an impact on drillability as well. One of these parameters is the rotation speed of the bit. This study investigates the effect of rotation speed of the bit on drilling performance. Drilling tests were performed in the laboratory using rotary core drilling and a diamond drilling machine. The relationships between the physical rock properties and the penetration rate were investigated on 15 different rock types and four different rotation speeds were applied to determine the effect of rotation speed of bit on drilling. The uniaxial compressive strength, density, and P wave velocity show strong correlations with the penetration rate. In addition, if the values of the physical and mechanical properties of the rock increase, the effect of the rotation speed on the penetration rate decreases, i.e., increasing the rotation speed of the bit slightly affects drillability on hard and solid formations. 1. Introduction Drilling is one of the most essential operations in the mining industry, beginning from the exploration phase and continuing throughout all stages of production to the end of mine life (Taheri et al. 2016). In addition, drilling is widely using in the construction industry and other engineering operations. Various drillholes (blastholes, injection holes, borehole, diamond wire holes in natural stone mines, etc.), are needed during development and production activities in underground and open-pit mines as well as in dam, tunnel, road construction and sewage systems. For effective drilling operations, it is first necessary to gather information about the formation to be drilled. Drilling should then be performed after selecting appropriate drilling equipment and drilling parameters (thrust, pressure, rotational speed, flushing). Prediction of the drillability of rocks is vital for planning and performing the drilling process. Although, drilling is affected by several factors, the most important ones are related to the geological and mechanical properties of formation (Protodyakonov 1963, Paone et al 1969, Tandanand and Unger 1975, Pathinkar and Misra 1976, Rabia 1985, Perrin et al 1977). Determining the penetration rate is vital for planning a project and calculating the operation costs. The prediction of drilling affects the selection of drilling equipment, the efficiency of drilling equipment, project costs and the process of drilling operations."

Jan 1, 2017

By Robert S. Ondrey, Robert A. Haney, David J. Atchison

The Mine Safety and Health Administration has conducted tests to determine the effectiveness of two methods for reducing diesel particulate emissions in underground coal mines. Both methods involved collection of the particulate material before being released into the environment. One method utilized a disposable pleated paper filter attached to the tail pipe; the other utilized a reusable wire mesh screen attached to the tail pipe. This paper describes the instrumentation and testing used to evaluate both control methods. Results of respirable dust and diesel particulate measurements made underground are presented and analyzed.

Jan 1, 1992

By E. D. Gálvez, L. A. Cisternas, R. Acosta-Flores, F. A. Lucay

Froth flotation processes are carried out in flotation cells that are grouped into banks, and these banks are interconnected, forming a flotation circuit. A literature review shows the existence of papers related to flotation circuit design based on mathematical programming. However, due to the complexity of solving the mathematical model in most of the work, it is considered that a small number of species is present in the feed to the circuit, which differs from practice. In addition, simple bank models are generally used. This paper presents a methodology for designing mineral concentration circuits that overcomes the problems mentioned. It allows the use of more suitable cell or bank models and the inclusion of several species. The methodology is based on two phases. The first phase identifies the set of optimal structures using discrete values of stage recoveries, solving several mixed integer linear programming (MILP) problems. In the second phase, the optimal design for each of the structures obtained in the previous phase is determined using a suitable model for the recovery at each cell or bank, which results in a mixed integer nonlinear programming (MINLP) model. The design of a copper concentration plant with eight species and the design of a zinc concentration plant with three species and five size fractions by species are used to validate the proposed methodology. The structure of the cells in the rougher and cleaner banks deliver structures that are novel.

By W. M. Ma, Daniel W. H. Su, K. Centofanti, Yi Luo, W. L. Zhong, Syd S. Peng

NTRODUCTION Surface subsidence monitoring is the most effective means for investigating the nature of, and developing the techniques for pre¬dicting the surface movement and deformation process. However, because of imperfection in survey equipment and field practices, the surface movement data collected from field survey are not error-free. Also due to lack of proper numerical techniques for computing surface deformation from the measured surface move¬ment data, a relatively large portion of the subsidence data col¬lected could not provide information other than surface movement. In a paper by Luo and Peng (1992), the sources and magnitude of errors in the measured surface movements using an electronic total station in subsidence survey are discussed. If the errors in the measured surface movement components are left untreated before calculation for deformation indices (i.e., slope, strain and curva¬ture), the errors will be carried over to the deformation indices and enlarged if improper numerical procedures are used in the calcu¬lation. It should be noticed that in protecting structures affected by ground subsidence, accurate surface deformation indices are much more important than surface movement. In order to improve the accuracy of the collected surface movement data and the calcu¬lated deformation indices, a number of numerical procedures are also proposed in the same paper. The proposed techniques include: a data smoothing technique for data pre-processing; and a number of numerical methods and/or procedures for calculating surface deformation indices from the measured surface movement data. DATA SMOOTHING Because of various factors, the measured surface movement data always contain errors, small or large. In order to better utilize the collected data, a data smoothing method is proposed to correct the errors in the measured movement data. The method uses the same concept as the influence function method (e.g., Knothe, 1957) on which many existing subsidence prediction methods are based. The data smoothing method makes necessary corrections on the measured movement for the point of interest according to not only the measured movement at this point but also those at the surrounding points. The contribution of a surrounding point in making the correction for the point of interest is inversely propor¬tional, in exponential form, to the distance between them. The new magnitude of a movement component at the point of interest (Zi*) is calculated by

Jan 1, 1992

By K. N. Han

The adsorption of gold onto activated carbon in iodide solutions was studied. The adsorption rates were determined as a function of temperature, salt concentration and pH, as well as activated carbon concentration. A kinetic model was developed for the adsorption. The adsorption rate was believed to be controlled by a combined mechanism of film diffusion and pore diffusion with the film diffusion having the most significant effect. Experimental findings were in good agreement with the model developed. The apparent activation energy was found to be 14.9 kJ/mol.

Jan 1, 1995

By R. G. Eggert, M. R. Walls

A mining CEO's willingness to participate in risky investment opportunities significantly affects a company's strategic-investment decisions. Decision-analysis techniques provide a mechanism for measuring a CEO's risk tolerance and ability to make formal comparisons of risk propensity among mining firms. The authors developed a methodology for measuring CEO risk tolerance. The findings from a confidential survey of mining CEOs are presented. The results from the survey suggest that: •mining CEOs are overwhelmingly risk averse when considering investment decisions; •CEOs of small mining firms are significantly more risk averse than CEOs of large mining firms; and •there appears to be some differences between Australian and non-Australian CEOs regarding their willingness to participate in risky investments. The results of this survey suggest that CEOs are pursuing objectives other than, or in addition to, maximizing shareholder wealth and that they act to reduce the financial exposure associated with strategic investments.

Jan 1, 1997

By Janusz S. Laskowski

The most important type of potash ores, sylvinite, contains sylvite, halite and a small percentage of insoluble gangue [sulfates (anhydrite), carbonates (dolomite), and clay minerals]. Primary normal long-chain amines are exlusively utilized to float sylvite from halite, but since mines are also adsorbed by insoluble slimes, the process requires prior desliming. This is carried out either by mechanical means, or by flotation of slimes and blocking off the adsorption centers on clays with the use of polyelectrolytes. Fractional crystallization is employed to produce fertilizer grade KC1 from disseminated ores with a high content of slimes. An extender oil is needed in addition to mine to float coarse sylvite fractions. The process is carried out in a saturated brine at mine concentrations exceeding the solubility limit and is strongly affected by temperature fluctuations. All these important features, which make this process differ from a conventional flotation, result from a high electrolyte concentration.

Jan 1, 1994

By Peter N. Loncar

Most miners dream of finding a gold mine sometime during their mining careers, but not very often do such dreams come true. On the tenth day of September, 1962, our dream of finding gold came true when the results of the third drill hole were received. This was undoubtedly one of the most exciting days of our lives. Little did we realize then that this was the beginning of a major discovery destined to became one of the largest gold mines in the country. Discovering and mining gold is not entirely new, however, to Eureka. County a old Lynn Mining District in northeastern Nevada. Since 1900 there has been sporadic activity, mostly consisting of small lode mines and placers. These have produced totally about $300,000; and existence of our orebody would probably have remained unknown had it not been for the United States Geological Survey. The USGS extensively mapped the Roberts Mountain Thrust and published a paper indicating that mineral occurred along this fault and in some places was gold bearing. Utilizing this information, our Newmont Exploration geologists located an area in which: drills were brought in to test their theories. By keeping flexible in our thinning and working, we were able to bring a raw prospect to a producing mine with ore reserves of eleven million tons in a short three-year period.

Jan 1, 1965

By Oscar Cabello, Luis Mendieta, Maribel Guzman

Mineral flotation processes generate large volumes of tailings, which must be disposed of efficiently and safely. In addition to dry stack disposal, the possibility of reusing these tailings as aggregates in shotcrete is an interesting alternative. Tailings samples from a mining operation in southern Peru were characterized by granulometric analysis, X-ray diffraction and Scanning Electron Microscopy. Concrete samples were obtained with different tailings formulations. The samples were subsequently subjected to geomechanical testing. The results showed that replacing 20% to 30% of the tailings with aggregates in shotcrete production achieved compressive strengths exceeding 30 MPa after 28 days of curing, with an energy absorption capacity of 500 joules. Results show that this shotcrete can be used in the support stage of the mining cycle in underground mining.

Feb 22, 2026

By I. E. Lewis, W. R. Hopkins

Flowsheet improvements, such as series/parallel SX plant configurations, discontinuation of plant sumps and improved filter pumping concepts, the use of in-settler baffle systems, and the Krebs and combined mixer-settler designs offer opportunities to reduce SX plant cost. Today's plants employ permanent cathodes and mechanical stripping, and the increased capital cost can be offset by labor savings and higher current densities. The wider use of HDPE and new cell construction materials also reduce capital cost. The "Portelex" type of relocatable design embodies such new, cost-saving measures in a simple basic plant. Organic inventory and losses are reduced by new, fast-settling, hybrid organic reagents with improved kinetics and selectivity.

Jan 1, 1991

By M. Sengupta

Surface mining in arctic regions is characterized by many unique problems. Continuous and discontinuous permafrost (perennially frozen ground) occurs in most of the arctic and subarctic areas. Permafrost presents special problems of slope stability. Stability of permafrost depends on its temperature, moisture content, and material type. Permafrost slope fails due to solifluction, disturbance of ice-rich slopes, and liquefaction. Drilling and blasting of frozen ground present special problems. Depending on their degree of saturation with water, freezing soils and rocks have a number of important characteristics that affect blasting efficiency. Metals used in mining equipment and mining structures require special selection. At low temperatures, many steels lose most of their normal ductility and toughness (resistance to brittle fracture). This paper discusses engineering solutions to unique problems of arctic mining.

Jan 1, 1988

By Tsunenori Shibata, Kazunori Jimbo, Kaoru Toya, Masafumi Matsumoto, Jinya Mitsui, Toshinori Tsuji

"The Toyama Line is under construction as a natural gas pipeline with a length of 102 km from Itoigawa City to Toyama City. A 2 km-long tunnel section of the pipeline that we are reporting here is being excavated in a mountain area away from an urban area. The geology under which the tunnel is constructed is collapsible fractured breccia slate and Holocene sandy soil. Other tunnels of the Hokuriku Expressway and Hokuriku Shinkansen are in service above the tunnel route. From the starting shaft on Toyama side, conventional tunneling was adopted to facilitate excavating the base rock layer and maintain enough distance from the Hokuriku Expressway tunnel. From the starting shaft on the Itoigawa side, TBM tunneling was adopted to cope with the unconsolidated soft ground for a 200 m-long section from the shaft. We will discuss the issues and countermeasures concerning the selection of a tunnel route and excavation methods, performance of both conventional and TBM tunneling, and underground connecting of these tunnels excavated by conventional (NATM) and TBM methods under a high groundwater pressure up to 1.2 MPa. INTRODUCTION AND BACKGROUND The International Petroleum Exploration Teiseki Co., Ltd. (INPEX) is constructing a high-pressure main pipeline network in the Toyama Prefecture area to promote the use and reliable supply of natural gas as shown in Figure 1. As part of the Toyama line project that has a total length of 102 km, A-1 construction, the nearest section to the tunneling starting point in Itoigawa City, where various tunnel excavation methods have been adopted to install the high-pressure pipeline 20 inches in diameter, a 2 km tunnel in the A-1 construction section discussed here is to be excavated by conventional and TBM methods in a mountain area. Based on environmental studies such as traffic jams due to frequent traffic of heavy vehicles disposing of soil, and the effects of dust, noise and vibration during construction, we selected the route to install the gas pipeline in a mountain area as shown in Figure 2, where the impact on the surrounding environment could be minimized."

Jan 1, 2016

By K. Galos

The paper presents increasing importance of mineral secondary and waste raw materials in the minerals management in Poland. Definition of mineral secondary and waste raw materials is proposed, according to current Polish law. On this basis, sources of various types of mineral waste raw materials are analysed. The special attention is paid to the wastes from mining and processing, wastes from power plants, and wastes from steelworks and other smelters. Other types of waste and secondary materials, such as metallic containers, glass containers, batteries, metallic wastes and scraps, are also taken into account. Analysis of sources of such materials is shown together with the main directions of their economic use. Available sources of information on manufacture and use of the mentioned secondary and waste raw materials are also analysed. Finally, for a wide range of waste materials, their current and expected significance as substitutes for some industrial and construction minerals in Poland is given.

Jan 1, 2011

By C. C. Stewart

Jim Walter Resources, Inc. operates four underground coal mines in Alabama. In 1986, during longwall recovery operations, sparks from a torch ignited methane that migrated onto the face after a roof fall. The fire quickly spread to the gob at the tailgate end of the longwall. The fire was successfully "area" sealed and mining operations resumed after five weeks. However, several problems were encountered during this process. This paper describes the events following the fire, methods used to control the situation, problems encountered, and steps taken to ensure preparedness for any future occurrences of this type.

Jan 1, 1993

By Z. Abdel-Khalek, Hassan El-Shall, S. Farrah, C. Boice

Selective adsorption and surface modification of minerals by surfactants is the primary step in the process of separating certain minerals with similar physical and chemical characteristics in the flotation process. In this study, microorgan- isms are used as surface modifiers for francolite and dolomite. Results of adsorption experiments with francolite and dolomite show that the microbes selectively adsorb to one of the minerals under specific operating conditions. In preliminary flotation experiments, it is found that the microorganisms enhance or depress flotation of the minerals leading to an increase in the efficiency of separation between the francolite and dolomite. The conditions leading to selective adsorption (surface modification) and subsequently to possible efficient separation of these two minerals are discussed in this paper.

Jan 1, 2002