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By D. Gatzemeier

The Jewett mine is a surface mine in central Texas, producing about 8,000,000 tons/year of lignite. The mine covers 46,000 acres of land. Approximately 430 people are employed by Northwestern Resources Company and through their efforts, the Jewett Mine is one of the most productive mining operations in the country. The Jewett Mine utilizes a unique structure of staff to convert Operations Research into plans which can be implemented at the "front line" level of the Operations Team. This planning not only makes the mine cost effective and efficient, but promotes creativity in mining, which promotes ongoing research to lower the cost of mining.

Jan 1, 1993

By Y. Guo, C. Cao

"China is rich in tungsten resource, but they are mainly associated minerals. The similar flotability of scheelite, fluorite, and calcite resulted in the difficult separation by flotation. This work summarized the current situation and the development of flotation reagents, technological process, and mineral processing equipments in China. Fatty acid served as the collector and water glass was the depressant to expand the flotability differences in traditional flotation technology. However the water glass inevitably influenced the flotation of tungsten minerals to a large extend, and the suppressed fluorite was difficult to recover by flotation. Abundant water glass lead to the bad settleability of the tailings and the tail water was difficult to circulate, resulted in serious environmental problems. Recent study proved that the selectivity of benzene armour hydroxyl oxime acid (BAHA) salts was adequate for the separation of tungsten minerals from fluorite, calcite and most silicate minerals without any depressant. By this way, sodium silicate was canceled completely in tungsten flotation, greatly improving the recovery of tungsten and the environmental problems caused by tail water treatment would be solved fundamentally. TUNGSTEN RESOURCES AND DISTRIBUTION IN CHINA China is rich in tungsten resources and the proved reserves accounted for 60% of the world's reserves [1]. However the wolframite has been dried up and the scheelite resources had become the main resource of the tungsten metal. Table 1 showed the most large and superlarge scheelite deposits in China. China has more than 40 large and superlarge scheelite deposits and the total metallic deserves is more than 3 million ton [2]. But most of the deposits were low-grade and the associated relationship was complicated. For example, scheelite was usually associated with wolframite, molybonite, bismuthinite, pyrite, fluorite, and calcite in Shizhuyuan and Yaogangxian mine."

Jan 1, 2016

By James R. Arnold, John O. Marsden

Introduction Metallurgical accounting practices have been revolutionized over the past 15 years by the introduction of low cost personal computers and easy- to-use spreadsheet software. The Chimney Creek metallurgical accounting system takes full advantage of these advances. Data is provided by a PLC-based process control system, IBM data logging, operator logsheets and assay results from an automatatic plant sampling system. The data is organized and stored in an IBM PS/2 system using Lotus 123 and customized accounting programs to provide a comprehensive information management system. Metallurgical accounting for gold plants should ideally provide information for the following: a) Gold production accounting b) Day-to-day process control and operation c) Metallurgical evaluation and process optimization The Chimney Creek system provides all of these while overcoming specific accounting problems presented by SAG milling a coarse feed, grinding in cyanide and dump leaching run-of-mine material. Process description Gold Fields' Chimney Creek mine is located 47 miles northeast of Winnemucca, Nevada, at the northern end of the Osgood Mountains. Ore is processed by a combination of dump leaching and milling processes. The dump leach operation treats approximately 2.0 million tons per year of low grade ore (0.030 oz/ton). Run-of-mine ore is top dumped in 40 foot high pads. The use of three solution ponds for leaching enables an intermediate solution to be recirculated to the leach pad to reduce the pregnant solution flowrate and increase gold tenor of solution to the carbon-in-column (CIC) recovery circuit. Gold recovery is approximately 65% by this method. The milling process employs a SAG mill-ball mill grinding circuit to treat 900,000 tons per year at an average grade of 0.19 oz/ton. The ore is crushed to minus 12" in a jaw crusher prior to feeding the SAG mill. Cyanide is added to the grinding circuit to start gold dissolution as early as possible. After grinding, leaching of the ore is continued in a unique two-stage counter current decantation circuit 1 with 12 hours of leaching between stages . 85% of the soluble gold is recovered from the first stage thickener overflow in carbon columns (CIC). The second stage underflow is treated in a scavenger carbon-in-pulp (CIP) plant. Ultimate gold recovery is over 95%. Loaded carbon from both the dump leaching and milling processes is pressure stripped by hot cyanide solution and gold is recovered from the resulting solution by zinc precipitation. The precipitate is retorted for mercury removal and smelted into bullion. The plant flowsheet appears in Figure 1. Data collection Data for daily metallurgical accounting is obtained from three sources: a) Plant sampling b) Process control system c) Operator logsheets All of the data collection for metallurgical accounting is based around the 12-hour shift operating schedule. Sampling All critical sampling for gold production accounting is performed by automatic samplers (Figure 2). Heath & Sherwood two-stage sampling systems are used for sampling all slurry streams (cyclone overflow, CIP feed and CIP tails). The automatic sampler consists of a pneumatically operated primary sample cutter and a continuous rotary secondary splitter. The cyclone overflow and CIP tails are the most critical samples since these are used to calculate gold into and out of the plant on a shiftly basis. The CIP feed sample gives additional information concerning intermediate dissolution and recovery

Jan 1, 1990

By K. F. Unrug

The research work reported in in this paper deals with the monitoring of roof behavior in a drift mine located in Eastern Kentucky operating in the Coalburg Seam. The thickness of the seam at the monitoring site ranges between 9 and 10 feet with the immediate roof changing from sandstone to shale then back to sandstone. Shale thickness varies between 0 and 2.5 feet. The characteristics of the immediate shaly roof were monitored with 38 dynamometers which were set up in three survey lines to cover the entire range of shale distribution. The dynamometers are capable of providing accurate load readings in the range of +/- 5 pounds. To closely observe the contribution of moisture toward roof deterioration the dynamometers were set up in intake and neutral airways. A television borescoping camera was used in conjunction with the dynamo- metric instrumentations at pre- determined observation holes to physically observe and record the separation process of the shale and sandstone stratum with respect to time. Monitoring took place between January 1985 through January 1986 in order to cover a full cycle of dry and wet mine conditions associated with the seasonal changes. Analysis of the data show a trend of roof deterioration induced by condensation and eventual penetration of moisture within the immediate roof bedding planes, leading to rapid disintegration of the mine roof.

Jan 1, 1986

By K. A. Natarajan

The relative significance of corrosive and erosive wear in magnetic taconite grinding is examined. The influence of different types of aeration, namely, nitrogen, air and oxygen on ball war was established for mild steel and high carbon low alloy steel balls. Ball wear data from dry and wet grinding tests are compared with those obtained in the presence of an organic solvent that does not promote electrochemical corrosion. 'Marked ball grinding, tests along with electrochemical measurements involving ball material and magnetite electrodes indicate that contribution from oxygen towards wear (corrosive wear) is relatively small and abrasive wear appears to be significant. Rheological properties of the slurry-appear to have an important bearing on the abrasive wear of grinding balls.

Jan 1, 1983

By W. R. Bull

This paper examines water-only cyclone performance for the cleaning of fine coal, and the effects of changes in feed flow rate, feed pulp density, and vortex finder diameter. A model is presented for performance simulation which can be used to predict products obtained based on feed washability data.

Jan 1, 1987

WELCOME to the world-class Cripple Creek district where gold exploration and production continue 95 years after the initial discovery. More than 21 million troy ounces of gold have been recovered, valued at greater than $7.8 billion using today's gold price ($371/oz). The Cripple Creek district is localized within and around the margins of a silica-undersaturated alkalic diatreme-intrusive complex. The diatreme appears to be comprised of three sub-basins: 1) a sub-basin east of the Cresson (Fig. 1); 2) a southwestern sub-basin between Victor and Cripple Creek; and 3) a northwestern sub¬basin within which the Globe Hill and Ironclad pits (Fig. 1) are located. The recognition of three separate basins was made by G. F. Loughlin and A. H. Koschmann (1935, Fig. 8) who prepared a contour map on the floor and walls of the composite Cripple Creek basin. The northwestern and southwestern sub-basins are apparent due to the discontinuous exposures of a partially exhumed ridge of Precambrian rocks (Fig. 1). The separation of the eastern and southwestern sub-basins was recognized in mine exposures where a fault-bounded ridge line extends from the vicinity of the Ajax mine toward the Precambrian "island" (Fig. 1).

Jan 1, 1986

By Dolf Vos

The balling section of the pelletizing plant at Hoogovens IJmuiden consists of 7 balling drums. Each with an average capacity of 100 tons of green pellets per hour. The balling drums are equipped with rotating scrapers and water-spraying systems. The scrapers are installed in order to restrict the growth of the race to a certain thickness. The spraying system is used to adjust the desired value of the moisture-content of the rewetted ground ore, the pellets and the race. The desired value is the value by which the balling- process is stable, good pellets are formed and surge occurs within certain limits. In October 1980 the construction of one of the balling drums has been modified. The rotating scraper was removed and the inner wall of the drum was supplied with a rubber-lining. In 1982 a second balling drum has been rubber- lined. At the same time the Tyler vibrating screen of this balling circuit has been replaced by a roller(bed)screen. By the end of 1983 all 7 balling circuits will be equipped with rubber-lined drums in combination with roller(bed)screens. The combination of these two modifications will improve the quality and the screen analysis of the green pellets, moreover resulting in savings on energy- and maintenance costs. This paper describes the influence of a rubber- lining on the balling process and the green pellet quality by carrying out in-plant testruns in November/December 1980. The testrun results have been compared with the results of a not modified balling drum.

Jan 1, 1983

By J. F. Childs

"INTRODUCTION Comprehensive overviews of the world-class talc deposits and related prospects in Montana were published by Olson (1976) and by Berg (1979). Both of these compilations include detailed descriptions and maps of the talc deposits and occurrences and were followed by a regional map and summary descriptions of the talc deposits published by Van Gosen et al. (1998). More recent publications, descriptions and field guides for some of the deposits include Underwood et al. (2014), Cerino et al. (2007), and Cerino (2002). The present paper focuses on some of the more recent ideas regarding talc formation that have developed since the publication of the earlier overviews. Olson (1976) reported that talc production from the deposits in southwestern Montana was over 200,000 tons in 1974 and that talc production had doubled between 1969 and 1974. The last year for which the U.S. Geological Survey published production records for talc by state was 1993. Production in Montana in 1993 was 350,000 tonnes (Virta, 1994). Remaining reserves are substantial at all three of the producing mines in the district. Minerals Technologies Inc., the parent company of Barretts Minerals Inc., stated in its 2014 annual report that it has reserves of 2,791,000 tons of talc. Imerys stated in its financial report for 2014 that it had 19,638,000 tons of proven and probable talc reserves at its North American mines. Although the Imerys reserves were not reported by individual mines or states, a large proportion of the total reserves would likely consist of the reserves at the Yellowstone mine, located south of Ennis, Montana. Talc mined in southwestern Montana is of high purity and is the quality used in a wide variety of applications including paints, ceramics, plastics, rubber, coatings, agriculture, cosmetics, and pharmaceuticals. GEOLOGIC SYNOPSES FOR MAJOR MINES AND COMMENTS ON REGIONAL DISTRIBUTION OF TALC OCCURRENCES The general geology of southwestern Montana is shown in Figure 1along with the locations of the three producing talc deposits in the area and the extent of pre-Belt marbles that host all of the talc mines and prospects. The term “pre-Belt” is used in the present paper because zircon and other radiometric data developed in recent years indicates that the metamorphic rocks that form the crystalline basement for the middle Proterozoic Belt basin in the Dillon Tectonic Block of southwestern Montana includes both Archean and Paleoproterozoic rocks (O’Neill et al., 1996; Foster et al., 2006; McDonald et al., 2012). An envelope or “corridor” has been superimposed on the geology in Figure 1 which encompasses all of the talc deposits that have a significant resource. This “talc corridor” will be discussed in later sections of this report. The more important talc deposits are discussed in this report section."

Jan 1, 2016

By F. N. Siddiquie, Mohd Shaif, Rajiullah Khan, Juned Alam

Manganese ore bodies of Banswara Mn belt were classified into stratiform and stratabound types, based on their mode of occurrence, distribution, and their chemical characters. These ore bodies generally composed of braunite, pyrolusite, cryptomelane/ psilomelane, wad, etc. The stratiform-type Mn ore bodies are conformable with the associated host rocks (Mn phyllite, etc.) and occurred in the form of layers, bands, etc., which are variable in their shape and size. These ore bodies are also strongly folded with the enclosing host rocks. The others, which are stratabound-type Mn ore bodies, also showed an intimate association with the associated host rocks. These types of ore bodies occurred in thin layers, pockets, lenses, stringers, etc. The classified ore bodies are confined with Kalinjara formation of Aravalli Supergroup of Paleoproterozoic age. The ore bodies are structurally controlled and well associated with phyllite, schist, limestone, quartzite, etc. The stratiform-type ore bodies constitute a marginal to low Mn grade and are also characterized by lower Mn content (26.19–39.24%) along with the Mn/Fe ratio of 7.16–12.23, while the stratabound-type Mn ore bodies are rich in Mn (35.92–49.64%) along with the higher Mn/Fe ratio of 14.15–23.97. However, the poor Mn grade along with high siliceous impurities of Banswara Mn deposits is subjected to them for intermittent mining activities in the past and, consequently, did not attract the scientific and industrial community for the evaluation of these resources. Therefore, the authors attempted this study in a scientific and systematic manner (mode of occurrence/distribution and possible methods for evaluation/exploration) to evaluate the potential of existed and newer Mn deposit resources in the Banswara Mn belt. The whole findings would be very much helpful for exploration/ mining geologist along with other concerned, to completely evaluate these Mn deposits in the future.

Aug 16, 2021

By Rodrigo Jerez

This paper describes a Mixed Integer Linear Programming model that was developed for planning the coal operations at Mountain Coals, Inc., in Kentucky. The model incorporates the use of stockpiles as practiced and allows the operator to find the least cost combination of raw coal feeds, washing densities and blending to produce the different quality coals as required by the coal contracts.

Jan 1, 1984

By T. Hollingsworth

The Boddington Gold Mine, located near Perth in Western Australia, has recently completed the construction of a new process plant. An overland conveyor system was installed to convey the ore from the primary crusher to the process plant. This paper will discuss the overland conveyor?s mechanical design including dynamic analysis and the selection of primary mechanical and electrical components.

Jan 1, 2010

By C. J. Im

As market conditions become more competitive, U.S. coal producers are faced with the increasing need to find methods of lowering production costs in their operations. One area worthy of investigation is the additional recovery of fine coal that is normally discarded in the preparation plant waste stream. United Coal Company is currently assessing the capability of the Deister Flotaire, a new application of a column flotation cell, to recover additional, saleable coal from preparation plant waste. This paper presents the technical data obtained to date. Work with a 0.76 m (30 inch) diameter cell installed in a plant shows considerable coal recovery is possible from a nominal 0.595 run (28 mesh) X 0 refuse stream.

Jan 1, 1986

By Samuel W. Woods

The Tacoma, Washington plant is one of six plants in the United States Gypsum Company's Acoustical and Mineral Fiber Division. The Tacoma facility was acquired in 1959 along with six other mineral wool plants from the American Rock Wool Company. Originally, the Tacoma plant was built as a carbide plant during the Second World War and after that was converted and operated as a mineral wool plant by several insulation companies. Through these early years, the use of raw materials at Tacoma consisted primarily of slags along with small percentages and various combinations of silica (in various forms such as gravel), limestone and basalt. These raw materials were melted in cupolas using coke as the heat source. Raw material usage and types as well as mineral wool production methods and equipment remained without major changes for many years.

Jan 1, 1983

By R. E. Driscoll

The exploration, geologist of necessity has to have a wide working knowledge of many specialties other than hiw own, First he has to use his own technical background to find a deposit,, of a mineral that is of interest, Once found, his problems are Just beginning, He then has to assume the role of an economist, an accountant, a mining engineer, a chemist, a metallurgist,, a salesman and what-have you, In the economic field, he must determine the marketability of either the ore or the refined mineral. He must gauge the supply and demand for the particular mineral he is interested in and make his best guess as to ultimate cash flow from a deposit over the estimated life of said deposit, He must then assume the role of a mining man and estimate cost of recovery, including an, evaluation of the most economic mining method, cost of supplies and labor, and again estimate a net cash flow. He must then determine amenability of ore to economic metallurgical methods, he must determine the legal status of the property involved and, after analysis of the specific situation, determine the best approach to a deal, After all of this he must sell it to the people who will put up the money and then put his deal together and sell it to the people who own the minerals, if that be necessary. Then he has to sit back, with crossed fingers and crossed legs wondering for some months, and in many cases even years, whether or not he is right. The expenditures required to open up a mine in this day of wild inflation are such that he has to be right, and the responsibilities are awesome.

Jan 1, 1958

By J. S. Hastings

Tertiary calc-alkalic to alkalic rocks of the Little Rocky Mountains in north-central Montana host low-grade heap-leachable gold-silver deposits being mined by Pegasus Gold Corporation. Total production from 1884 through 1985 is estimated at 22,625 kilograms (727,414 ounces) of gold. This includes 10,774 kilograms (346,400 ounces) recovered by Pegasus between 1980 to 1986 from 20,318,000 tonnes (22,396,000 tons) of ore grading 0.960 grams of gold per tonne (0.028 ounces per ton). Silver production during this latter period was 24,556 kilograms (789,500 ounces), but reliable silver statistics prior to 1980 are not available. Ore reserves as of January 1, 1986, were estimated to be 35,380,800 tonnes (39,000,000 tons) grading 0.720 grams per tonne (0.021 ounces per ton). Present ore production is 5,533,920 tonnes (6,100,000 tons) per year at a 0.45 to 1 waste to ore strip ratio. Current annual metal production is about 2,644 and 5,288 kilograms of gold and silver respectively (85,000 and 170,000 ounces of gold and silver respectively). The Little Rockies were formed by a calc-alkalic to alkalic magma penetrating through the Precambrian basement into the overlying Paleozoic and Mesozoic sedimentary rocks. This intrusive center is Dart of the Central Montana Alkalic Province, a region comprised of twelve separate intrusive centers aligned in a northeast trending belt measuring 200 by 400 kilometers (124 x 248 miles). The ore deposits are structurally controlled epithermal systems which vary from deeper narrow veins to shallow, wide, low-grade stockworks, breccias and intensely fractured "sheeted" zones. The shallow types are now being exploited. Primary mineralization consists principally of gold and silver associated with pyrite, native gold and silver, sylvanite, calaverite, and hessite. Alteration is broadly classified as weak argillic. Pyritization, kaolinization, silicification and feldspathization are the dominant forms of alteration. Fluorite is a common hydrothermal gangue mineral.

Jan 1, 1987

By Robert J. Brison

The intent of this paper is to try to answer the complex question: "How much grinding capacity should be designed into a new mining - milling project?" Much work has been devoted to the technical aspects of grinding, the "how" of grinding. But, in the writers' opinion, the economically important subject of optimizing grinding capacity in mill design has not received the attention it deserves, at least not in published literature. For the purpose of this paper it is necessary to distinguish clearly between optimizing operation and optimizing design. Optimizing operation involves making the best use of the available plant and equipment. Much excellent work has been done and is being done in this area. In operation, one can make tradeoffs of production rate and recovery, or recovery and grade, to maximize profits. However, this must be done within the limitations imposed in the design stage. Flexibility is limited by the existing plant. In project design, on the other hand., there are no preexisting physical limitations except as imposed by nature itself; the planners and designers have considerable latitude in their efforts to optimize the overall project. They have complete control over a large number of important design variables from the mine to the finished product. The grinding process design is one of these variables. It not only determines the capital cost charges for grinding and the maximum grinding capacity that operating management will have to work with, but also determines the range of capability of the auxiliary equipment, which fixes the degree of flexibility possible in operation. This paper is concerned with optimizing design rather than operation. The terms "optimum" and "optimize" are sometimes used in a technical sense in connection with grinding, recovery or grade. In this paper, these terms are used only in the economic sense. In this age of working large deposits of ever lower grade ores, it is in¬creasingly essential to design projects and plants for optimum economics, based on the most applicable economic. criteria. Since grinding represents a large part of both capital and operating cost of the project, and largely determines percentage recovery of metal, it should be included as one of the factors in optimizing the project design. This paper is written primarily with reference to medium to large copper concentrators employing conventional wet grinding. However, the principles involved should be applicable to other ores and other methods of grinding.

Jan 1, 1972

Computerized financial models can be used in all phases of the mineral industry from setting exploration targets to projecting profit plans for producing mines. In this presentation, I will use the example of an exploration company entering a new district to trace the application of financial models through the following intermediate phases. 1. Hypothetical analysis and strategy 2. First encounter of mineralization 3. Preliminary drill results - decision process 4. Feasibility studies 5. Post-feasibility negotiations 6. Producing mine 7. Acquisition of producing mines or mineral properties. I will conclude with a brief discussion of the mechanics of the financial models that we use at Wright Engineers Limited. As we progress through the seven phases, the availability and accuracy of the data will parallel the complexity and application of the financial models. However, the same basic financial models are utilized throughout the seven phases. I will begin by suggesting that the exploration group is somewhat autonomous and has the mandate to explore in Western Canada.

Jan 1, 1979

By Stephen C. Tadolini, Colton Cook, Cody Hildreth, Frederick Cybulski

"Broken and jointed ground is extremely hazardous and requires unique stabilization techniques to protect worker and critical entries. Bolting techniques, even the most advanced with pre-load to create roof compression, can leave large gaps of unconfined and separated roof. This roof can also be susceptible to water inflows which only exacerbate the support problem. These types of conditions existed on long term development main entry accessing several future longwall panels. The geotechnical assessment identified well-defined jointing systems that also permitted water to flow between the roof separations, which “lubricated” the roof material and minimized any frictional advantages. Chemical injection of a Polyurethane material, Minova Carbopur WS, was placed beyond the bolted horizon to move the water to the rib lines and reinforce the fractured and broken roof. The injection material permitted the effective use of bolting patterns and helped ensure long-term stability of these critical entries. The paper describes the evaluation techniques, design patterns, basis for chemical selection and application, and results and recommendations.BACKGROUNDThe injection of mine and underground civil structures using polyurethane (PUR) has been ongoing for over 50 years. The applications in mining have included gate road stabilizations, longwall set-up and tear-down entries, and simple consolidation of coal mine roofs. PURs have also been used for roof stabilization during longwall shield recoveries. Polyurethane injection was initially developed by the Bergbau-Forshung GmbH, a German coal mine research institute, in the early 1960s (Jankowski, 1972). The product became a standard stabilization method in Germany after its commercial introduction in 1971 (Knoblauch, 1994), and was successfully manufactured at the Minova Essen, Germany location for over 50 years. With the recent closing of the German underground mines, that manufacturing facility has been closed and moved to Katowice, Poland, where production continues today Injection products are also being successfully manufactured by Minova in Australia and the United States.Polyurethane injection in underground coal mines is used in difficult ground conditions in fractured immediate and main roofs. It is also common as a rock stabilization remedy to prevent longwall face caving during shield removal. As presented in the case study, polyurethane was applied to minimize the inflow of water from beneath a stream channel while providing reinforcement and consolidation of the fractured roof that had lost confinement. Polyurethane is a two-component system (Part A and Part B) that is injected into a borehole and can chemically bond to the rock, not relying on friction or mechanical interlock to provide support. The material is injected under pressure, coupled with a low viscosity and small particle size; it flows into roof fractures and separations, which are the paths of least resistance. New developments in low viscosity PUR materials allows penetration of cracks as tight as 0.002 inch (0.05 mm) wide. This also allows for the closures of extremely small cracks to minimize the inflow of water, even if the water is under pressure. Combinations of designed expansion properties and low viscosities make the materials ideal for minimizing and stopping flows of water from underground structures."

Jan 1, 2019

By Cesar A. Busnardo

The carbonatite orebody in Jacupiranga is situated some 230km (140-mi) southwest of Sao Paulo and is mined by Serrana S/A de Mineragao, producing an apatite concentrate for fertilizer production and a calcite tailing for cement manufacture (see Figure 1). The orebody (Table 1) is mined by open pit and the total production is 4.5 million mt/year of carbonatite ore with a further 2.2 million mt/year of overburden. The carbonatite low-grade ore (Table 2) is fed to the concentration plant at 460 mt/h , comprising of four parallel lines of grinding, by rod mills 2.7m x 4.5m (9 x 15-ft), operating in closed circuit with hydrocyclones. The grinding circuit product is deslimed in four stages using hydrocyclones and the deslimed product is conditioned with corn starch and subsequently floated, using fatty acids as collector to, recover the apatite.

Jan 1, 1985