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By Kathleen Y. Knoebel

This paper describes a graphical mini computer system called MPASS 2 (Mine Performance Analysis/Simulation) which has been designed to conduct analysis of underground room-and-pillar mining operations using both conventional and continuous mining methods. Dynamic, graphic displays of mine face machine activities are presented on the CRT screen to provide extensive visibility into underground mining activities. MPASS 2 consists of: an interactive inputting system that graphically creates a room-and-pillar mine and describes the mine when production is initiated; a time-step simulator that produces statistical summaries of shift activities and uses CRT screen graphics for accelerated-time display of machine activities and delays; a statistical analysis subsystem for analyzing mine performance data; an industrial engineering system that permits users to enter actual machine activity statistics and replay mine operations on the CRT screen; and a data management system to store historical performance information on mine characteristics and operations. MPASS 2 operates on a Hewlett-Packard 9845B mini computer with 450 K bytes of extended memory, and is written in H-P BASIC. It has been installed at Freeman-United Coal Mining Company in West Frankfort, Illinois and at the U. S. Department of Energy Pittsburgh Mining Technology Center. Applications include production system simulation, industrial engineering analysis, production scheduling, new equipment evaluations, and training.

Jan 1, 1982

By Sean Harvey

One of the manifestations of the dynamically induced failures in deep coal mines is the violent ejection of coal from the ribs. A possible protection against such failures is the use of a specifically designed dynamic support system with reinforcement units having the sufficient capacity to absorb the kinetic energy of the dynamic failure and a skin support that can adequately contain the disintegrated coal. With this method of mitigation in mind, a recently introduced yielding rock bolt, trade name Roofex, has been identified (Harvey and Ozbay, 2009) as a possible energy absorbing component of a dynamic support system. According to the manufacturer?s specification, the Roofex bolts can yield 300 mm (or more) displacement while holding 80 kN pull load. In order to assess the performance of this support unit in coal ribs, a series of in situ pull tests performed in two coal mines in Colorado. The results show that, under conventional pull test loading conditions, Roofex yielding bolts perform very close to their claimed specifications, thus showing a potential for their use as the main energy absorbing component of a dynamic support system. Further studies are required to confirm the in situ performance of these bolts under dynamic loading conditions and also to develop a containment component for a dynamic support system for the mitigation of dynamic coal rib failures.

Jan 1, 2009

By David S. Bolin, Gary R. Peterson

INTRODUCTION In both the United States and Canada, a company making a public offering of securities must comply with regulations which have been promulgated by Federal and/or Provincial Legislatures. This paper focuses on the regulations pertaining to reserve reports required by the United States Securities and Exchange Commission (SEC). SEC RESERVE FILINGS Reserve reports made to the United States Securities and Exchange Commission are the only reserve reports which are directly regulated by the United States government. The requirements for SEC reserve reports are set forth in the filing forms as shown in Appendix A, from Item 17A of SEC Form S-18. These reporting requirements, which are intended to protect the investing public from inaccurate or misleading claims, are primarily oriented to S-1 or other filings for new stock issues but must also be followed for annual 10K reports which must be filed annually by U.S. public corporations as part of the Corporate Annual Report. These undertakings require independent audits of reserves, mine designs, plant facilities and a general economic evaluation of the planned or existing operation as part of the backup documents for filing. An ore reserve is defined by the SEC as "That part of a mineral deposit which could be economically and legally extracted or produced at the time of the reserve determination". This definition is unchanged since it was last

Jan 1, 1988

By Richard Keith Corbin

INTRODUCTION With the world media full of predictions that the price of gold will quadruple in three years (Maybury, R.J., 1988), and with financial forecasters and strategists touting opportunities to make 400% in gold (Skousen, M., 1988), explorationists and entrepreneurs are scurrying to find enough gold to feed the global gold fever created. At the same time, gold deposits in the United States and other developed and intermediate countries are becoming less attractive because of environmental restrictions, radical reductions in tax incentives, and depleting reserves, causing people in the mining industry to begin looking at opportunities for foreign investment in gold mining concessions in lesser developed countries (LDCs). Meanwhile, LDCs are responding with chamber-of-commerce aplomb in marketing their opportunities. In the face of all this frenzy and hype, targeting gold mining concessions in LDCs for foreign investment may be done more objectively by employing a systematic approach. For this paper the SHOP rating system (Corbin, R.K., 1987), which considers factors of the LDC's stability, hospitability, ore occurrence, and profitability potential is used. The result is that a tiny banana-growing republic in Central America, first discovered by Columbus and named the "Rich Coast'' because of the many gold adornments worn by its Indians, has been rediscovered and emerges as a classic LDC gold target.

Jan 1, 1988

By J. Egan

The recovery of gold by ore leaching is influenced by the size of the particles and the chemical environment. Within the experimental error associated to the testing of gold ore, results of a series of leaching tests conducted with natural ores rather than monosized samples confirm that gold dissolution increases with decreasing ore particle size. The tests also indicate that the dissolution of gold in the ore within a size interval is weakly affected by the intensity of the size reduction method.

Feb 27, 2013

By D. L. Purcell, B. T. McClure, J. McDonald

The U.S. Bureau of Mines has completed a laboratory evaluation of exhaust emissions from a diesel engine using an oxygenated diesel fuel. The fuels tested were soy methyl esters in a neat (100%) form and low sulfur, petroleum number 2 diesel fuel (D2). The engine tested was a Caterpillar 3304, indirect injection, naturally aspirated, 75 kW, diesel engine that is typical of engines used in underground mining applications. The objective was to determine the extent to which oxygenated fuels, such as methyl esters, reduce diesel particulate matter (DPM), and their influence on upon gaseous emissions such as total hydrocarbons, CO, NOx, NO2, formaldehyde, and other exhaust emissions. Heavy- and light-duty transient tests were used to simulate load cycles typical of mine applications. The soy methyl ester fuel produced greater amounts of volatile DPM (organic material) but much less nonvolatile DPM (carbon soot) for overall DPM reductions. A diesel oxidation catalyst (DOC) typical of the type commonly used in metal and nonmetal mines was tested with both fuels. The DOC further reduced the volatile and total DPM when used with the soy methyl esters, but increased the total DPM for D2 due to sulfate formation. The soy methyl ester fuel reduced CO and hydrocarbon, and NOx emissions. The DOC further reduced CO and hydrocarbon emissions.

Jan 1, 1995

By K. Kavouridis

The competitiveness of power production from lignite depends on the ability of coal industry to meet CO2 emissions limits, as specified by the Kyoto protocol. According to the National Allocation plan issued by EC, power plants should reduce CO2 emissions to a certain level, other-wise they will be obliged to cover the difference buying CO2 certificates through the Emission Trading Scheme. These charges will increase the operating cost of current units, as well as the investment cost for new units. To predict the increase in the marginal cost of electric power produced from the current plants of Western Macedonia, an emissions factor (CO2 t/MWh) for various units has been computed. Based on the algorithm used, this factor depends on the calorific value of the lignite, the efficiency of the power plant and the oxidation factor of the unit. For lignite plants with efficiency ~37%, CO2 emissions factor ranged from 1.19 t/MWh to 1.32 t/MWh. The increase in the marginal cost of kWh, as compared to the values of CO2 certificates, is higher in units fed with low quality lignite and worsens if the efficiency of the unit is low too. Also the presence of calcareous minerals in lignite increases the CO2 emissions and consequently the cost of power generation.

Jan 1, 2006

Beneath some of New York?s most iconic buildings ? The Met Life Building, the Helmsley Building, the Waldorf Astoria ? crews are busily at work on the Metropolitan Transportation Authority?s long-awaited East Side Access (ESA) project. In fact, it is 14 floors beneath the famed Grand Central Station where one of the centerpieces of the project, the new Long Island Railroad (LIRR) station terminal, is being blasted and carved into shape. When completed in 2016, the $7.3-billion ESA project will increase LIRR?s capacity into Manhattan and significantly relieve congestion at Penn Station. Currently, 37 LIRR trains per rush hour roll into the crowded Penn Station where many riders must then transfer to subway trains to complete their commute. When completed, the ESA tunnels will bring an estimated 160,000 riders directly to Grand Central Station, saving those riders 30 to 40 minutes. Studies have found that more people work within walking distance of Grand Central than Penn Station. ?The benefits of the project are tremendous,? MTA Capital Construction President Michael Horodniceanu told more than 340 industry professionals attending the UCA of SME?s George A. Fox Conference in New York on Jan. 26. ?The ESA is the first expansion of the LIRR in 100 years. It will increase the East River tunnel capacity by 50 percent and will help support job growth around Grand Central.?

Jan 3, 2010

By S. Yerel

In a mineral processing plant, the determination of a preventive maintenance schedule is one of the most important maintenance policies. In this study, to determine the preventive maintenance schedule for the Emet Colemanite Mineral Processing Plant in Turkey, a mean quality control chart was constructed using the historical concentrate B2O3 grade data. The effect of preventive maintenance scheduling on B2O3 grades was monitored using the mean quality control chart. It was determined that recovery increased after each preventive maintenance scheduling. Close examination of the mean quality control charts indicated that there were three periods that showed different grade characteristics. These were identified as the period ?prior to preventive maintenance,? the period ?after preventive maintenance? and the period ?requiring preventive maintenance.? These periods were compared as two independent samples by using the Kolmogorov-Smirnov test. Application of this test for interpretation of the mean quality control chart enabled the authors to analyze the system effectively, and it showed that the preventive maintenance for this plant should be scheduled at four-month intervals.

Jan 1, 2007

By P. L. Crouse, S. J. Lubbe, M. J. Kabangu

A selective extraction and separation of zirconium by solvent extraction with 1-octanol is proposed. The process is based on the dissolution of the metal basic carbonates in hydrochloric acid in the presence of potassium fluoride, using 1-octanol as extractant. The effect of several process parameters, including hydrochloric acid and potassium fluoride concentrations, reaction time, and phase ratio between the aqueous and the organic phase was investigated. Zirconium is enriched in the organic phase. The best extraction and separation results were obtained with the basic carbonate dissolved in 10% hydrochloric acid and 1.5 M potassium fluoride. The optimum reaction time was 15 min with an organic to aqueous phase ratio of 2:1. Based on the selectivity of zirconium over hafnium in the organic phase, a McCabe-Thiele diagram was constructed. A near complete stripping of zirconium from the organic phase was achieved using a 3 M sulphuric acid solution. Additional studies are required in order to determine the reaction mechanism and the chemical speciation of the current investigation.

By James Diekmann

The Disputes Potential Index (DPI) is a computer program designed to help team mem¬bers assess the likelihood of contract disputes on a construction project. The program's predictions are based on data from 159 construction projects that encompass a variety of public and private projects. The impact of three categories of project characteristics are included in the DPI program, specifically, people, process and project characteristics. Ultimately, DPI returns an overall project score that indicates the likelihood of exces¬sive contract disputes. The output of a DPI analysis can be used as part of a contract readiness review or to define the need for extraordinary dispute avoidance procedures. This paper examines the development of DPI and presents the results of DPI analyses on several tunneling projects.

Jan 1, 1995

By G. H. Sedahmed, S. A. Nosier, M. H. Abdel-Aziz, A. A. Mubarak, M. A. El-Naggar, E. G. Abdel-Aziz

The performance of a rotating fixed bed reactor in recovering copper from industrial waste solutions by cementation is studied under various conditions. The rotating fixed bed is made of stacked woven steel screens to take advantage of two features of screens: the ability to present large area per unit volume and their ability to promote high turbulence. Variables studied are initial CuSO4 concentration, bed rotation speed, mesh number of the screens and bed thickness. The presence of baffles was found to increase the rate of cementation. The data were correlated by a dimensionless mass transfer correlation suitable for the design and operation of large scale cementation reactors.

By G. H. Sedahmed, S. A. Nosier, M. H. Abdel-Aziz, A. A. Mubarak, M. A. El-Naggar, E. G. Abdel-Aziz

The performance of a rotating fixed bed reactor in recovering copper from industrial waste solutions by cementation is studied under various conditions. The rotating fixed bed is made of stacked woven steel screens to take advantage of two features of screens: the ability to present large area per unit volume and their ability to promote high turbulence. Variables studied are initial CuSO4 concentration, bed rotation speed, mesh number of the screens and bed thickness. The presence of baffles was found to increase the rate of cementation. The data were correlated by a dimensionless mass transfer correlation suitable for the design and operation of large scale cementation reactors.

The Cutoff grade optimization is very critical to the open pit production scheduling. In case of single mineral deposits, algorithms have been developed for determining cutoff grade policy that maximizes the net present value (NPV) of yearly cash flows. For deter-mining the cutoff grade policy for projects with two minerals including stockpiles the problem becomes much more complex. The purpose of this paper is to present fundamentals of a generalized cutoff grade optimization algorithm that will maximize the NPV of a project subject to mining, milling, and marketing constraints. Benefits of the methodology developed are demonstrated on three different case studies.

Jan 1, 1997

By Sah Rameshwar, T. Umadevi, K. S. SRIDHARA

In the magnetite iron ore pelletization process, oxidation of magnetite followed by sintering of the oxidized magnetite (hematite) is desirable. Optimum preheating time & temperature and roasting time & temperature is required to get the desired properties of the pellets with magnetite, hematite, and hematite–magnetite blend. In order to utilize the magnetite resources in a current induration furnace, which is designed for hematite resources, detailed pelletization studies have been carried out to optimize the firing cycle for magnetite concentrate as well as magnetite with hematite concentrate. Under optimum conditions, such as preheating temperature 1000–1150 °C, preheating time 10 min, roasting temperature 1250 °C and roasting time 7.5 min, the cold compression strength (CCS) of magnetite roasted pellets was 325 kg/p, and this was due to recrystallization of secondary hematite particles, and development of the strong slag bond between primary and secondary hematite particles. The strength of hematite concentrate pellets was 260 kg/p. From laboratory studies, it was found that without disturbing the induration furnace firing cycle, which is designed for hematite ore ~5%, magnetite concentrate can be used along with hematite concentrate in pellet blend and the strength of the pellets was 270 kg/p. As the magnetite concentrate increases in the blend beyond 5%, the preheating zone residence time should be increased or a supply of extra oxygen is required. Laboratory as well as plant investigation has shown that the addition of magnetite to the hematite mix blend improved the strength of the pellets compared to hematite pellet alone.

Oct 26, 2020

By Roy Norcross

For the past few years Caro's acid has been used for the treatment of cyanide containing slurry effluents, providing a feasible alter­ naive to other slurry treatment processes including !NCO SO2 / Arr and ferrous sulfate. Presently, mines using Caro's acid gen­erate their own Caro's acid onsite making a relatively low quali­ty product. It was at this point where we, at Degussa Corporation, decided to focus our efforts on engineering a Caro's acid genera­tor capable of cost effectively producing a high quality Caro's acid solution, thus reducing operating costs significantly. Caro's acid or peroxymonosulfuric acid is not a new chem­ical nor is it new to Degussa. The product was named after Heinrich Caro (1834-1910), a German chemist who first described its synthesis and its oxidizing properties in 1898. Degussa has been producing the potassium salt of Caro's acid as the triple salt, 2KHSO5 - 2KHSO4 - K2SO4, called Caroat®, for over 30 years. Caroat® is used for household and denture cleansers, as a bleaching agent in dish washing detergents, in printed circuit board etching and for cyanide destruction in the plating industry. From our experience in producing Caroat® Degussa developed its new Caro's acid based DegOX™ technology for the treat­ment of cyanide containing effluents from gold and silver mines.

Jan 1, 1996

By J. A. Mejia

The combination of high-resolution X-ray microtomography (HRXMT) image analysis and Lattice-Boltzmann Method (LBM) simulations has demonstrated the ability to describe real multiphase flow problems in fine coal filtration. The single component multiphase flow He-Chen-Zhang LBM model was used to simulate filtration with actual HRXMT images of pore network structures produced in filtration experiments. The analysis performed on coal, silica, and glass bead filter cakes showed that particle shape and wettability are two of the most important factors in the retention of moisture during filtration.

Feb 23, 2014

By D. Einarson, B. Strickland

The decision to accelerate development of Stillwater Mining’s East Boulder Mine was made in March of 1998. It required the completion of conceptual designs by July of 1998. This was accomplished through teamwork and close cooperation of mine personnel, engineering firms and vendors, all working toward the common goal of developing an efficient and workable design. Early in the project, representatives of Stillwater Mining, Kilborn International, Parsons Brinckerhoff Transit and RailSystems, Continental Conveyor, and H.A. Simons met to develop methods to bring the mine into production at a highly accelerated rate and to solve potential bottlenecks, including the movement of personnel, materials, and muck through a 5.6 km(3-1/2 mile) adit. This interaction, including companies not normally associated with the mining industry, led to innovative approaches and designs produced by Kilborn Engineering and Stillwater Mining.

Jan 1, 1999

By Susana Bolhão Muiños, José Hipólito Monteiro, Martin Frank, James R. Hein, Henrique Garcia Pereira, Fátima Abrantes, Tracey Conrad, Luís Gaspar

In spite of all the work that has already been done on ferromanganese deposits, studies on the Atlantic Ocean occurrences are still in their infancy and there is a clear need for investigations concerning the origin, distribution, and resource potential assessment of these deposits. Nevertheless, studies already carried out on northeast Atlantic seamounts indicate the general presence of ferromanganese deposits of hydrogenetic origin, i.e. deposits formed by direct precipitation of colloidal, hydrated metal oxides that are scavenged from the water column on hard-rock substrates. The hydrogenetic precipitation promotes the enrichment of ferromanganese crusts in many trace metals, most of which are of economic interest, such as Co, Ni, Te, rare earth elements, and platinum-group elements and thus ferromanganese crusts are considered an important metal resource.

Sep 1, 2014

By A. Acar, E. T. Tuzcu, Y. O. Vural

"In order to sustain the operations in chromite processing plants, due to concentrate selling cost, plants are in need of optimization in terms of capacity and recovery increase. In this study, DAMA Engineering carried out a methodological study for the purpose after a detailed sampling campaign in a plant which is situated in one the main chromite zones in Turkey; 1 The current status of the plant was investigated quantitatively with the bottlenecks, Plant overall efficiency in terms of recovery, Efficiencies of the particular equipment (mill, screen, gravity circuit), 2 A new circuit was proposed with the available equipment, 3 The new circuit that is product of modeling and experimental effort, was evaluated quantitatively as if it is a running plant, After 4-5 months continuous effort, the capacity of the plant was almost doubled (37 tph to 70 tph) and the plant overall recovery was increased from 48% to 63% by grinding adjustments and additional shaking tables theoretically. It was shown that the plant may move into profit with the minimum amount investment using readily available system. INTRODUCTION TO THE CURRENT PLANT The objective of the study is to increase the capacity and recovery of the chromite plant owned by Kurmel Group, Akmetal Inc. The complete study is given elsewhere (DAMA, 2016). The plant is situated in one of the main chromite zones in Turkey; Aladag. The current capacity of the plant is around 35 tph and the overall recovery declared by plant engineer is around 47 %. The chromite plant mainly has 3 units; crushing, grinding and gravitational circuits. The crushing circuit has 3 stages; a jaw crusher, a secondary cone crusher and a tertiary cone crusher operating in closed circuit with a vibrating screen with the aperture size of 15mm. In grinding circuit, a rod mill (2.44 6m x 3.6) and a ball mill (2.13 x 2.3m) are used for primary and secondary grinding, respectively. Derrick screens are used for the size separation. Additionally, for the size classification of the system, hydrosizers are used and each size fraction is sent to the shaking table sets. The middling product of the tables is subjected to re-grinding with a ball mill with the dimensions of 2.1 x 2.9 m. The capacity and the recovery are affected by several bottle necks; hydrosizers’ pure classification, primary/secondary mill power vs capacity problems, re-grinding product’s high slime content and so on. These combined factors made the plant to run in low recovery and capacity. Hence, DAMA was asked to make a study to investigate current status of the plant and propose a new solution to increase capacity and recovery of the plant. The conceptual flowsheet of the circuit is given in Figure 1 below."

Jan 1, 2017