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By M. Kaya

The main purpose of this study was to design a modular/mobile coal preparation plant with a capacity of 300 t/h for Seyitömer B3 vein (almost 70% of the whole SLI deposit). Firstly, coal washing properties and washability curves were determined by sink and float tests. Then, equipment sizing, selection, flow sheet development, economic evaluation, investment and operating costs were determined for coarse (-150+18mm), fine (-18+0.5mm) and slime (-0.5+0.1mm) coals. Economic evaluation of the proposed flow sheet showed the feasibility and profitability of the investment.

Jan 1, 2006

By Ron Parks

High Pressure Grinding Rolls (HPGR) was introduced to the mineral processing industries in the mid-SO's as a tool for comminuting raw and processed materials. This tool made its an impact in the Cement Industry where it was used as a pre-grinder on existing ball mills, raw and finish grinding in a mill circuit and other various applications. This concept was a big success where the cost of power was high along with the desire to increase capacity. The HPGR reduced the power requirement and increased the capacity in the ball mill due to the finished product produced by the HPGR and the micro fractures in the coarse rock, which reduces the power required to finish grind the rock. This unit has found acceptance in many other industries including diamonds, iron and other selective applications. The diamond industry uses this tool for selective grinding purposes since the kimberlite rock is considerably softer than the actual diamonds. Therefore within a bed of material, kimberlite is crushed to fines and the diamonds are liberated and unharmed. The iron industry primarily uses this tool for concentrate comminution; however, there are installations using this tool as a pebble crusher and in an AG-pebble mill circuit.

Jan 1, 2000

By Arthur P. Chaves, John A. Meech, Vanessa M. Torres

Process choice for a refractory gold ore can become a controversial issue, especially at the early stages of a project. This happens since at preliminary stages, a simple economic comparison among the main process options is not possible as the differences are usually smaller than the precision of estimates. This paper presents a methodology to assess the suitability of each available technologies using a heuristic approach, were technical, economic, operational and environmental aspects are taken into account using a neural network methodology. This methodology is embedded in an expert system for gold ore process design, Intelligold, which is in the final stages of development.

Jan 1, 2000

By G. M. Bernard

This paper provides an overview of the various methods and techniques for transporting and stacking ore on heap leach pads. Towards this end, brief discussions of the various methods and techniques important to this process are presented.

Jan 1, 1993

By S. Bhagwat

Coals capable of emitting 2 lbs SO2/106 Btu heat input must be defined as high sulfur coals. This is because electric utility plants built after 1971 may not emit more than 1.2 lbs SO2, and those built before 1971, and regulated under the State Implementation Plans (SIP), may exceed the 2 lbs S0 limit only under closely defined restrictions concerning ambient air quality and prevention of air quality deterioration. Coals produced in Kentucky, Illinois, West Virginia, Ohio, Pennsylvania, and Indiana account for 77% of SO2 pollution potential and are, therefore, the subject of this investigation. These coals have suffered market share losses in the 10 years from 1974 through 1984. This is due to their sulfur content as well as their lack of price competitiveness with low sulfur western and imported coals. Kentucky and West Virginia have been able to increase their compliance quality coal production substantially, but other states have largely been unable to do so because of nonavailability of low sulfur coal deposits. Assuming that the current relative productivity and cost competitiveness of coal producing states will not change significantly by 1994, this paper makes two projections of coal production in the selected states. In scenario I, the current clean air regulations are assumed to apply until 1994, and coal production in the selected states is projected to in¬crease by about 6% in 1994 compared to 1984. In scenario II, it is assumed that acid rain legislation will be implemented, which will adversely affect the markets for high sulfur coals. Coal production in the selected states under this scenario is projected to decline about 10% between 1984 and 1994, jeopardizing up to 13,000 mining jobs. The author concludes that better coal quality and greater cost competitiveness are both essential to stem the market losses and to regain strength.

Jan 1, 1988

By Fred Woodcock, A. R. Laplante

A laboratory technique is presented that uses the Knelson Concentrator and a relatively small sample to predict the amenability of a given gold ore to gravity recovery. The technique applies to develop­mental orebodies as well as retrofitting existing plants. Justification for this approach is discussed. Actual results of the technique applied to existing and prospective circuits are presented and discussed.

Jan 1, 1993

By S. K. Kawatra, S. J. Ripke

Iron ore pellets use bentonite clay as binder at dosages from 0.5to 1.0% (10 to 20 pounds per ton) of moist iron ore concentrate. Bentonite is typically shipped hundreds of miles from Wyoming to the Lake Superior iron ore district. It is therefore best to know how effective a bentonite will be before it is shipped and used to bind concentrate into pellets. Current tests of bentonite effectiveness include: plate water absorption, methylene blue uptake, free swell, exchangeable cations, and glycolated layer expansion. However, these tests have many disadvantages: First, they only measure the ability of a bentonite to expand, disperse, or absorb, not how well it will bond. Second, most of the tests require up to 20 hours to perform. Bentonite only has a few minutes to interact within the concentrate before it is indurated (sintered). These long-term tests may not reflect the true behavior of bentonite. Third, the tests are tedious and often results are inconsistent between different iron ore concentrates, labs, and technicians. Fourth, some of the testing equipment is difficult to procure. Fifth, procedures are often difficult to standardize. In this paper, the Binder Effectiveness Strength (BESt) test to evaluate binders for iron ore pellets is presented that: measures the ability of bentonite to bond, requires only about two hours to complete, is simple and reproducible, and utilizes readily available equipment that has been standardized for decades.

Jan 1, 2003

By C. N. Speltz

The cost of transportation of industrial minerals is frequently higher than the cost of the product. Where a minc, industrial mineral plant. or customer is served by a single railroad, that single railroad, because of lack of competition, may increase rates and/or provide inadequate service so that the economics of that mine, plant or customer are adversely affected, or so that the level of service precludes satisfactory performance. Transloading of industrial minerals from rail-to-truck or truck-to-rail in order to improve economics and sales of product is not new. However, transloading to reduce freight costs or improve inadequate service caused by a lack of competition in the rail industry, is a relatively new concept brought on by the recent mergers of many of the main line railroads, both in the eastern and western United States. For example, with completion of the Burlington Northern/Santa Fe and the Union Pacific/Southern Pacific mergers, the western United States has only two mainline railroads. The industrial mineral producer, in order to reduce the cost of transportation, or increase the level of service, must evaluate potential transloading opportunities in light of higher prices and reduced service brought on by reduced railroad competition.

Jan 1, 1998

By T. D. Dreger

In the spring of 2009, Suncor Energy Inc. technical personnel saw an opportunity to improve planning and mining of overburden material in order to address aggressive construction goals and increased mining complexity. By tying together current and historical equipment performance, geological model information, and material observation in the field new operating elevations for the shovels were developed. At the same time, methodology of recording and reporting overburden movement through the Modular Mining DISPATCH system was changed. The result of this first stage of improvements was an increase in construction-grade material available at the face. The personnel involved realized that other opportunities were available to build on the initial successes and establish processes that would stand up to attrition and experience levels. A cross-functional technical team was assembled to identify ways of further improving workflows around overburden mining. Some of the opportunities realized include greater alignment between planning, reporting and operations as well as development of reporting tools that help steward Mine Operations to the plan. All of which have resulted in Suncor meeting or beating its forecast overburden targets. The cross-functional technical team continues to seek out new and better ways of doing business so Suncor can continue to deliver on its commitment of outstanding performance and results.

Jan 1, 2012

By Ronald D. Hill

Acid mine drainage is the result of the oxidation of pyrite and similar iron sulfide material and the release of iron and sulfuric acid into the environment. In addition to the acid water flowing from underground and surface mines, spoil materials in surface mines are acidic and will not support good vegetative growth; thus erosion is a major problem. Lime and limestone are the major neutralizing agents used to treat these acidic conditions. Lime is the reagent preferred by industry for treating acid discharges, although a few companies use limestone. Agricultural lime- stone is used to "sweeten" acid spoils.

Jan 1, 1974

By McGuirk. C. H.

The Port of Conneaut, long regarded as a leader in advanced bulk material handling technology, recently incorporated into its existing facility a new, multi-million dollar coal transfer-storage system. While the basic principles of conveyorized bulk material handling remain unchanged in the new system, design modifications such as rotary dumping of railroad cars, automated car feed to dumper, belt rip detection for conveyor belting, bucket wheel continuous production, and other innovations make The Pittsburgh and Conneaut Dock Company's complex worthy of classification as the "Port of Tomorrow - Today". The Pittsburgh & Conneaut Dock Company, the "Port of Tomorrow - Today", 1s a bulk materials storage and transfer facility located on Lake Erie, 68 miles east of Cleveland, 30 miles west of Erie, PA., and 138 miles north of Pittsburgh. Figure 1 shows an aerial view of the facility. It is designed to handle over 25 million tons per year of metallurgical and steam coals, direct shipping ore, fine ores, concentrates, pellets, limestone, and dolomite. Inbound shipments of iron ore and limestone are received from Minnesota, Michigan, Labrador, and Quebec. Coal arrives from Pennsylvania, Ohio, Virginia, West Virginia, and Maryland. Rail service is provided by the Bessemer & Lake Erie Railroad Company.

Jan 1, 1980

By Terry I. Mudder, Michael M. Botz

In general, the cyanidation of silver ores requires higher con­centrations of cyanide in comparison to gold ores to affect simi­lar leaching rates and metal recoveries. The requirement for high cyanide concentrations in a silver ore leaching circuit may translate into higher operating costs, however with operation of an acidification-volatilization-reabsorption (AVR) plant to recover and recycle tailings cyanide, cyanide consumptions can be significantly reduced. At each of the currently operating AVR plants in the world, overall cyanide consumptions have been reduced by approximately one-half by recovering and recycling tailings cyanide. In addition, the AVR plants have reduced tail­ings cyanide concentrations to less than 20 to 30 mg/L WAD cyanide and reduced potential adverse impacts to wildlife in the tailings impoundments. This paper presents an analysis of the application of A YR to a silver ore leaching operation which has a CCD/Merrill-Crowe circuit included in the metallurgical plant.

Jan 1, 1998

By B. A. Hancock

It is not at all surprising that causticized potato and potato derived amylopectin starch solutions performed much better than their parent starches. Some preparation is required to rupture the starch granules to effect the polymeric adsorption and interparticle bridging necessary for selective flocculation. In laboratory work comparing the deslime performance of causticized and autoclave cooked laboratory corn starch solution preparations, it was found that higher deslime weight rejections, with attendant proportionally greater iron unit losses, occurred with the causticized starch. These results may be specific to the ore involved but they do suggest that cooking and causticizing cause different starch granule rup- ture and/or starch breakdown, which have an effect on desliming response. I calculated from the data in the article that the slimes product grades were high - 24.3% and 20.3% Fe when 53.7% and 54.5% Fe concentrate products were obtained, respectively, in Table 4, and 21% Fe with a 62.6% Fe concentrate in Table 5 - using the natural tailings sample, which had a head of 34.3% Fe. It may be advisable for the authors to consider different starch preparations in future investigations. The combination of upgrading and selectivity results presented in Table 4 are not as good as the authors suggest. The authors' claim that a system has been developed to produce saleable concentrates from the Kudremukh tailings is quite disconcerting. There are many hurdles yet to be crossed before commercial application of selective flocculation becomes possible because differ- ences between the very small-scale laboratory tests conducted and commercial application are rather large. Among the many differences are varying circuit feed grades that will occur from use of tailings, the apparent face that much lower tailings grades will be encountered in practice (it is much easier to achieve a high concentrate grade with reasonable recoveries using 34.3% Fe tailings as in the study rather than 25.3% Fe tailings grades that the plant apparently averages), the hydraulic nature of the thickeners used in operations compared to the static system used in laboratory tests, the different size distributions that will be obtained from a plant closed grinding- classification circuit, and differences in water used in a plant operation and the laboratory. The authors wrote that it was necessary to overgrind to be sure that the coarse gangue would not settle with the iron oxide floccules. This situation is likely to be exaggerated in commercial operations where it is assumed cyclones would be used for classification. Because cyclone classification is greatly influenced by particle densities, there will probably be an even greater difference in size between the iron and gangue particles in the plant, which would make the gangue slightly coarser still in relation to the iron. This would make the selective flocculation-desliming separations using the procedure employed by the authors even more difficult and, using the dispersant system the authors employed, greater overgrinding would be required. To grind finer to minimize the coarse gangue in the flocculated iron oxides is quite inefficient and appears not to broach the problem. The actual problem appears to be insufficient dispersion of the ground pulp. In this situation, addition of a dispersant would likely be required to attain a sufficiently high pulp dispersion level to efficiently effect a selective flocculation-desliming separation. Although the very coarse particles would still have a tendency to settle with the floccules, it probably would be found unnecessary to overgrind as much as indicated. Use of an optimum combination of dispersant and pH modifying reagents may also significantly improve the selectivity of desliming. Additionally, although it is possible that sufficient dispersion may be obtained by pH control alone in some situations, it is quite probable that added dispersity was obtained in the reported work from using distilled water. It is research experience that distilled water enhances dispersion. In commercial operations it may not be expected that sufficient dispersion will be obtained by pH control alone, unless the water used in the process is by nature quite dispersive. Overall, a change in the Kudremukh tailings dispersant scheme appears necessary where a dispersant is used in conjunction with a pH modifying reagent. With this change, different dispersion-flocculation responses will result that would have to be further evaluated. Therefore, it is still an open question whether an efficient and effective selective floccula- tion separation using Kudremukh tailings may be obtained that will produce saleable concentrates.

Jan 1, 1987

By C. Babbitt, J. O’Green, N. I. Jayaraman

In many mines, dust-laden air from an entry being driven by a continuous miner will contaminate the intake air to the roof bolter operator and other downwind personnel. Through a US Bureau of Mines (USBM) contract, Foster-Miller Inc. has evaluated several control techniques to reduce the respirable dust exposures of downwind personnel. One fan and tubing technique consisted of bypassing the miner-generated dust directly to the section return. The results of the evaluation of this technique revealed that reductions in dust concentrations of 90% or more can be achieved at downwind roof bolter locations. A second method was to clean the dusty air from the upwind continuous miner by using a dust collector. The cleaned air was then supplied to the bolter through collapsible tubing. An underground evaluation showed reductions of 82% to 96% when the dust collector was operating. A third method was to reduce the quantity of dust contributed by the miner to the return airstream. A water-powered scrubber was installed over the throat area of the continuous miner. More than 1.18 m3/s (2500 cfm) of dusty air moved through five tubes with dust collection efficiency exceeding 75%. Underground evaluation results showed that return dust concentrations were reduced by about 60%. This paper discusses the ventilation and dust control techniques used for personnel downwind of the continuous miner.

Jan 1, 1987

By G. L. Black

Choosing a mining method for an underground ore body is a complicated and often iterative process. Advances in technology give the design team an overwhelming array of possibilities for methods and equipment. Hecla's recent discovery of the deep Gold Hunter ore body has given the staff at the Lucky Friday Mine the exciting challenge of determining the optimum mining method. Taking an ore body from prospect to production requires traditional resource characterization, including drilling, delineating and modeling. Developing the mining plan is an evolving process, changing with each new piece of information as the project progresses through exploration and development.

Jan 1, 1998

By G. S. Adisoma

To address the problem of grade estimation in a general three-dimensional shape and the uncertainty associated with the estimate, the technique of jackknifing/block kriging short-cut is proposed. A new estimator called jackknife kriging is introduced first. Through the jackknife variance, a confidence limit for the reserve grade estimate can be calculated. Unlike the kriging variance, which is more a measure of data configuration and is independent of data values, the jackknife variance reflects the true variability of the data. This approach provides a simple way to set a confidence level for global estimation of resources.

Jan 1, 1995

By F. Bourgeois, J. A. Herbst, R. P. King

The ultrafast load cell (UFLC) has proved to be an exceptionally good device for the study of the fundamental processes associated with the impact fracture of particulate material. A new high- sensitivity UFLC has been commissioned at the Utah Comminution Center for the study of low-impact energy single-particle fracture. The force-time histories of individual fracture events have been measured. The force and energy absorbed at crack initiation have been measured at several particle sizes. The mass specific energy for fracture and the associated breakage function have been determined. The distributions of particle breakage energy and particle strength have been measured as a function of particle size.

Jan 1, 1992

By P. A. Anderson

Innovative solution management is being used at Coeur-Rochester, Inc. to increase bullion production and decrease overall costs. New operating programs call for reduced solution application rates to the heap to increase pregnant stream values at a lower and less costly plant flowrate because silver and gold extractions are equal regardless of leach solution application rate. Solar heating is used in the summer months to increase the core temperature of the heap for use in the winter months thus increasing silver extraction rate. This paper outlines the programs now in effect and the savings incurred because of them.

Jan 1, 1989

By Dwight R. Coles

The solving of complex metallurgical flowsheet calculations by hand is, at best, a tedious job which often proves that engineers, too, make mistakes. The high cost and long lead time associated with manual flowsheet solutions have led several organizations involved in research, development and construction of extractive metallurgical processes to search for computerized systems which will solve flowsheet calculations. Although design flowsheet programs have been developed by the chemical industry, the ability to solve flowsheets involving particulate solids is usually overlooked. A new computer applications system has been developed at Fluor Mining and Metals which has been designed to accommodate the type of design flowsheets required by the minerals industry. By employing the sequential modular computation technique, a library of metallurgical pro- cessing routines may' be accumulated which are used by a universal executive system. This technique enables rapid solution of new process) .flow- sheets with only a minimum of additional programming effort. The implementation of the FLEXMET flowsheet solution system is the subject of this paper. Some of the major features of the system which are examined include interactive input data handling, automated flowsheet calculation order arrangement, flexible accomodation of unit operations models and advanced management of recycle and specification control calculations.

Jan 1, 1982

By Ottmar Burghardt

Sintering of iron ore has undergone a dramatic development world-wide. Today, the annual world production amounts to approximately 600 million tons. At present, the sintering process in competition with pelletizing, seems to offer certain advantages inasmuch as it allows the use of solid fuels. Also, its charging behaviour in the blast furnace is, in general, considered as being better than that of pellets. This is true, in particular, for the charging behaviour and the gas permeability in relation to the grain size. Moreover, instead of charging limestone into the blast furnace, for instance, the basic components which are necessary for the burden materials can generally be supplied in a simpler and more cost-effective way by using basic sinter instead of basic pellets. While in sintering, with basicity rising to the range of 1.6 to 1.8 CaO : SiO2, the capacity increases and the sinter quality shows improvements in most of its characteristics, the pro¬duction of basic pellets generally requires a higher fuel rate, when compared to acid pellets, while production capacity decreases and some of the quality characteristics deteriorate.

Jan 1, 1982