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By Scott W. Harrison, Richard E. Aaseng

In 1993 Ispat Inland Mining Company began mining its Laurentian ore reserve, which has six distinct ore types that are extremely variable. Initially batch processing was necessary to optimize mining equipment utilization. The variability as found in the ground was compensated for in plant operation, which proved ineffective. When the last of the six ore types was introduced in 1997, production, quality, and cost were seriously impacted. In-pit blending was the solution developed by the process management team to provide the plant feed required to economically process all six ore types in the Laurentian reserve.

Jan 1, 2000

By Robert C. Cifelli

INTRODUCTION Background and Objectives Underground coal mining is a vital component of West Virginia's economy. However adverse environmental effects including ground subsidence and aquifer dewatering are often associated with such mining activities. Many families in northern West Virginia still rely on private water wells and springs for domestic water needs. In such areas where underground coal extraction and land subsidence have occurred, a disruption of the ground water flow system commonly exists with subsequent drainage of water to lower levels that may extent as deep as the mine workings; this causes loss of water supplies to landowners and represents a nuisance to mining companies 2 This report represents a summary of an M. S. thesis project in geology at West Virginia University by the senior author (3). The intent for this study was to document the effects of underground coal removal on ground water levels at selected mine sites in northern West Virginia, as observed from water wells, springs, and streams. This research should be useful to coal companies and regulatory agencies and aid in recommendations of future water well locations and specifications in areas of existing or proposed underground coal mines.

Jan 1, 1986

By Christine E. Turner-Peterson

Pore-filling organic material concentrated uranium to form sandstone-hosted primary uranium deposits in the Jurassic Morrison Formation of the Grants uranium region, New Mexico. Petrographic observations and radiometric ages for primary ore in the Westwater Canyon Member require that the organic material was emplaced early in the diagenetic history of the host sandstone; in fact, organic material was emplaced before major compaction. This inferred early emplacement constrains models concerning the nature and origin of the organic material and thus also constrains models of ore genesis. Reconstruction of the burial history of the basin indicates that Late Jurassic-Early Cretaceous time, the interval of inferred emplacement of the organic material, was probably not a time of hydrocarbon generation and migration. Nuclear magnetic resonance analyses, elemental abundances, and isotopic studies provide further constraints on the nature of the organic material, and data from these studies are consistent with a humic acid rather than an oil origin. In addition, the overall tabular shape of primary uranium orebodies and the way these orebodies are suspended in the host sandstone mimics Recent deposits of humate, the precipitated form of humic acids. The critical clue that favors a humic acid origin for ore-related organic material is provided by the nature and patterns of postdepositional alterations that are spatially and temporally related to primary ore, specifically destruction of detrital magnetite and ilmenite (iron-titanium oxide) grains. Humic acids are implicated in the destruction of iron-titanium oxide grains because these organic acids are one of the most effective natural agents in leaching of Iron from these grains. Thus, timing constraints, chemical evidence, orebody geometry, and the nature and patterns of ore-related alterations favor a humic acid origin and suggest that an oil origin is highly unlikely. Because alteration of iron-titanium oxide grains tracks the pathways of humic-bearing solutions through the host sandstones, it is possible to trace these solutions back to their source. Alteration patterns in the Westwater Canyon Member suggest that the humic-bearing solutions originated as pore fluids in the mudflat facies of the overlying Brushy Basin Member and moved into adjacent sandstones during early dewatering of the mudstones. The humic acids precipitated, by the process of cation loading, in tabular layers. Uranium was concentrated within these tabular layers by complexation with the humic acids to form primary uranium orebodies.

Jan 1, 2013

By V. W. Smith

For the past 50 years, the primary crushing of stone at the Dolase Bros. Co. Richards Spur Quarry. 13 miles north of Lawton, Oklahoma, has been accomplished by a Traylor 42-inch gyratory crusher. The production capacity of the primary system, consisting of a feeder, grizzly, and the gyratory crusher, was approximately 2100 tons per hour. Shot-down scone was hauled from the working face about one mile to the feeder by a fleet of Caterpillar Model 773's and WABCO 60- and 65-ton trucks. In order to maintain production, nine to ten trucks and four Caterpillar Model 992 front-end loaders were required to be operational at all times.

Jan 1, 1986

By Joseph G. Selmeczi

Lime and limestone-based SO2 scrubbing processes have demonstrated reasonably good success in removing low concentrations of SO2 from flue gases. While most of the operating problems experienced in the early days of scrubbing have been worked out, problems usually increase and removal efficiency drops with increased amounts of SO2 present in the gas stream. In order to overcome these difficulties, yet still taking advantage of lime and limestone as the lowest cost neutralizing agents, a host of so-called double- alkali systems were developed. These processes take advantage of cations such as Na+ and NH4+ capable of forming highly water soluble bases or basic salts, such as hydroxide, carbonate or sulfite, which having been neutralized or acidified by the absorbed SO2 can be regenerated with a lower cost base such as lime.

Jan 1, 1974

By J. A. Finch, B. J. Huls

Accurate level detection is required to make full use of level in optimizing control strategies for flotation columns. Techniques based on pressure and electrical conductivity are compared. Pressure and conductivity profiles give good agreement on level. Level calculated from single and multiple pressure values became more accurate using, in order, one, two and three sensor locations. The level estimate remained in error, however, because, unlike the collection zone, froth zone bulk density varies with height. A conductivity probe continually updating the conductance profile is a practical method of obtaining an accurate level.

Jan 1, 1990

Adsorption experiments were conducted at two different solids loadings, to investigate the mechanism of oleate adsorption on apatite. Adsorption density at pH 10 was found to be dependent on solids loading in an oleate concentration region where surface precipitation could occur. Analysis of adsorption isotherms indicated three distinct regions of adsorption. In the region I (below the region of calcium oleate precipitation), molecular adsorption was observed. Simultaneous molecular adsorption and surface precipitation occurred in region II, while surface precipitation was predominant in region III along with some bulk precipitation. Correlation between flotation of apatite with sodium oleate and the mode of oleate interaction with the surface is established.

Jan 1, 1986

By James W. Guider

Of all the technology available to the iron blast furnace operator, raw materials preparation is by far the most important. Superior raw materials have been basic to the success of the Japanese steel industry, and they are just as essential to the American steel industry in winning its competitive battle against foreign government subsidized steel imports. Therefore, the mine operator and the ore beneficiation engineer must strive to produce the highest quality raw materials possible to meet the precise demands of the modern blast furnace and steel plant.

Jan 1, 1978

The process design of a metallurgical plant follows logical steps, one built on another, to define the circuit requirements. The methodology used and documentation produced is the same for a pre-feasibility study, feasibility study or a complete design, regardless of the process complexity or the commodity. The only difference is the amount of detail developed at each stage. SRK Consulting, an independent, international consulting practice that provides focused advice and solutions to clients, mainly from earth and water resource industries, has consulted on many mining projects around the world. The company was formed in 1974 and now employs more than 1,600 professionals in more than 50 offices on six continents. According to SRK experts, the first element in plant design is collecting metallurgical testwork or operating data from an existing plant. The testwork identifies the process, the metallurgical recoveries and product qualities and establishes the process parameters for economic recovery of the commodity. Test samples must represent both the whole orebody and the feed over the life of the mine, showing the mineral?s variability. With this data available, the process design can be developed.

May 1, 2013

By Rusty Winn

"R.E. Janes Gravel Co. is an aggregates producer is located along a paleo-channel of the Ogallala formation (locally known as the Slaton Channel) approximately 48.3 km (30 miles) southeast of Lubbock, TX. In an attempt to beneficiate the 25.4-mm (1-in.) concrete aggregate product, a log washer was installed in the processing line to liberate and remove fines (clay) from the finished product. The introduction of this extra cleaning step increased fines in the finished product, exacerbating the original problem. Several other processing options were investigated before a geological analysis was undertaken to try and define the lithology of the formation and formation characteristics in an attempt to alleviate this problem.Initial assessmentsThe mined resources are mid-Miocene to early Pliocene (16-4 mya) in age and is the eastern exposure of the Ogallala formation of the Southern High Plains escarpment. The Ogallala formation consists of coarse-grained alluvial sediments in paleovalley channel ways from the Rocky Mountains with fine Aeolian and paleosol deposition on the uplands across the High Plains region of the United States. Locally, these Rocky Mountain sediments from New Mexico were transported and deposited in a paleochannel that is approximately 0.805 km (0.5 miles) wide and 15.25 to 18.3 m (50 to 60 ft) in depth. As this channel cut across the Southern High Plains it eroded local rock sources of Late Cretaceous limestones and Triassic sandstones and mudstones incorporating them into the younger Ogallala depositional sequence.Depositional historyThe channel currently being mined is a nontypical Ogallala deposit. The Ogallala in the panhandle of Texas is divided into two units, the Couch and the Bridwell. The Couch is the older of the two and exhibits alluvial sedimentation of thicker and larger gravel (up to 76.2 mm or 3 in.) deposits fining upward to Aeolian sedimentation and thick friable caliche deposits. The Bridwell overlies the Couch and is characterized by alluvial sedimentation, a distinctive red tint and smaller gravel components (typically no larger than 25.4 mm or 1 in.) fining upward to Aeolian sedimentation and thick, well-indurated caliche cap. The Slaton Channel divides these two units and shares lithologic components of both, yet is lithologically distinct due to its Cretaceous Age limestone gravels that can be < 3.66 m (12 ft) in size. Caliche/calcrete is a calcareous (CaCO3) deposit that forms in the B horizon of soils as a rain water leachate of CaCO3 from the upper A horizon."

Jan 1, 2014

By Frederick P. Agterberg

It can be useful to model the mean grade values for a metal in mineral deposits containing that metal as representing the extreme value tail of a lognormal frequency distribution for the concentration values of the metal in rocks of all types. Results for copper and zinc in the Abitibi area of the Canadian Shield are compared to results previously obtained for the Canadian Appalachian Region. The lognormal model is also applied to a set of 162 large gold deposits in the Abitibi area. In the second part of the paper, 1311 large and small gold deposits in the Abitibi area are modelled as discrete events. By means of a newly developed spatial clustering model it is possible to predict the variances of random variables for frequencies of deposits in cells of different sizes.

Jan 1, 1979

By J. Fastle, M. Weinstock

The block cave mining method utilized by PT Freeport Indonesia (PTFI) generates fines and allows the inflow of water. Both constituents have contributed to unfavorable characteristics: an increase in ore material plasticity and fluidity. Unfavorable material needs to be monitored and managed as it passes from intermediate ore stockpiles through feeders and then to milling operations. We describe an implementation of several Video Data Analytics (VDA) algorithms on smart cameras to quantify the potential fluidity and plasticity by measuring the apparent velocity and agglomeration of material flowing through ore feeders. This approach to VDA on smart cameras is a cost effective, self-contained, solution to identify these unfavorable characteristics. The solution allows the operators to manage the related operational risks, maintain safe production and govern feeder rates when material is unfavorable, which is expected as PTFI proceeds deeper into the underground orebody

Mar 2, 2022

By M. C. Baumann

The Getchell Mine is located in Humboldt County, Nevada, approximately 70 km northeast of Winnemucca. Slope management has been a critical factor in the feasibility of mining operations since they began in the early 1930&apos;s. Although underground entries began in 1937, underground production was limited because hanging walls consisting of clay gouge and crushed rock tended to collapse into the workings. Controlling these collapses required extensive timbering. Due to these poor ground conditions, surface open-pit mining was the primary mode of production from 1938 to 1967 with only minor contributions from underground operations. Mining was suspended in 1967 due to economic pressures. From 1960 to 1967, the previous operator mined the property in three open pits. Initially, these pits were constructed with footwall benches, but these failed. These failures were aggravated by construction of 60° slopes in footwalls with shale partings dipping into the pit at 43° to 60°, resulting in large planar failures and wedge failures. In response, the previous operator adopted a slope parallel to the bedding planes.

Jan 1, 1993

By R. P. King, S. Middlemiss

A method is developed to convert a measured distribution of fracture energies to the equivalent work index. The method assumes that the energy required to grind the material from the feed size distribution to the product size distribution is equivalent to the sum of the impact energies that are required to reduce the feed material by successive single impacts to the required product size. The method was tested by measuring the fracture energy distributions for quartz and comparing the resulting calculated value of the work index with the work index for this material measured using the conventional Bond laboratory procedure.

Jan 1, 1998

By Terry A. Ring

Sand bed filters are used to remove large and small particles from liquid streams. The large particles are removed by the straining action of the filter bed and the small particles are removed by particle deposition on the surface of the bed particles. Particle deposition, while being essential for the filtering action of colloidal particles, is not the only process that occurs in the filter bed. Other processes that occur are (1) the substrate becomes filled with particles limiting further deposition, and (2) some deposited particles are resuspended. The sum total of all these processes determine the performance of a filter bed.

Jan 1, 1982

By P. Soros

Rich iron ore deposits were discovered during the 1960&apos;s in the mountain range of Serra dos Carajas, State of Para, Brazil, near the headwaters of the Tocantins River some 400 miles southwest from the state capital of Belem. (See Fig. 1 and 2). The key to the successful exploitation of this deposit was the development of an efficient an economical transportation system. The rugged terrain, and the dense tropical vegetation of the Amazonian jungle and the irregular coastline with its high tidal range presented severe obstacles to the planning and building of such system. Starting in 1972 extensive surveys and studies were carried out by Soros Associates on behalf of CVRD to determine the optimum way of transporting the ore from the mine site to the markets, most of which are located overseas. Overland transportation to the coast, loading into seagoing vessels and the ocean voyage to the ports of destination was treated as an integrated system in these studies.

Jan 1, 1986

By A. J. S. Spearing, G. Bylapudi, K. Mondal

The mining industry is a major consumer of rock anchors in the United States. Due to the high humidity in the underground coal-mining environment, the rock anchors corrode and lose their load bearing capacity, which, in turn, reduces the life expectancy of the ground support. This creates operational difficulties and a number of safety concerns (Li and Linblad, 1999). Research on rock anchor corrosion has not been adequate in the past and the effects of several factors in the mine atmosphere and waters are not clearly understood. One of the probable reasons for this lack of research may be attributed to the time required for gathering meaningful data. Underground water samples from different mines in the Illinois coal basin were collected and the major chemical content was analyzed and used for laboratory testing. The corrosion performance of the different commercial rock anchors was investigated by techniques such as laboratory immersion tests in five different corrosion chambers and potentiodynamic polarization tests in simulated ground waters based on the Illinois coal basin. The tensile strengths were measured for the selected rock anchors taken every three months from the salt spray corrosion chambers maintained at different pH values and temperatures. The corrosion potential, corrosion current and the corresponding corrosion rates of the #5, #6, #6 epoxy-coated and #7 forged-head rebar steels, #6 and #7 threaded-head rebar steels were measured in the pHs of 5 and 8 at room temperature. The open circuit potential (OCP) readings of the different rock anchors were recorded in three selected underground coal mines (A, B & C) in the Illinois coal basin and the data compared with the laboratory electrochemical tests for analyzing the life of the rock anchors installed in the mines with respect to corrosion current measured.

Jan 1, 2010

By Edward F. Divers, J. Drew Potts

Powered dust-filtering helmets (dust helmets) have become increasingly prevalent in the underground mine environment in recent years. Many longwall operations use dust helmets to reduce the respirable dust exposures of miners required to work downwind of crusher, roof support and shearer operations. While continuous mining sections are usually less dusty, use of diesel equipment represents a new potential health problem. The U.S. Bureau of Mines recently conducted a study to determine the efficiency of a dust helmet on diesel-size particulate. Two underground evaluations were conducted on continuous mining sections that were using diesel haulage vehicles. Model No. AH21 Racal airstream helmets equipped with AS22-3 prefilters, AS23-3 main filters and AS60476 tyvek full-face seals were tested. Helmets were placed on mannequin heads and mounted in the ram car cabs. Andersen Model 298 (eight-stage) personal cascade impactors were used to sample air inside and outside of the helmet. Impactor stages 8 and the final filters were analyzed to determine submicrometer (0 - 0.93 µm) particle concentrations. Results from this study showed that the dust helmet was 94% (± 3% at 95% confidence level) efficient on submicrometer particles. Typically, very little coal dust is observed in the submicrometer size range, therefore, these particles were assumed to be from diesel exhaust. Results from this study indicate that proper use of the dust helmet on continuous mining sections that are using diesel haulage vehicles may be beneficial to the health of miners.

Jan 1, 1991

By Agne Rustan

INTRODUCTION This work is a continuation of the preparatory study by Rustan and Stöckel 1979 (3) and (4) of the possibilities to introduce automatic mine ventilation in Swedish mines and construction works. The preparatory study has been financed by the Swedish Board of Technical Development. In the study it was recommended that an automatic step by step control of the fans near the working place due to diesel exhaust emission would be the best solution. A more advanced alternative would be to regulate the fresh air continuously in proportion to the contamination. The latter alternative has been studied by Boliden Mineral Co in the Udden mine. In this study it was found that the air supply could be regulated continuously but it was very important where the sensors feeling the contamination were placed. An intense study of the environment underground is now being planned by our division together with specialists from the National Board of Health and Safety, The Swedish Work Environment Fund, LKAB and the local Governmental Inspection of the Workers Safety. Different gases, radon, dust, airspeed, moisture temperature and pressure is planned to be measured continuously and correlation between the parameters is going to be established to decide the best measurement parameters for regulating the system. The best situation of sensors is also going to be studied. Despite this work hasn&apos;t been done yet this paper covers some of the problems which could be encounted with continuous regulation. In this report the environment has been studied during the test with step by step regulation of fans by radio. Diesel vehicles are the largest polluters under ground in Swedish mines and we have therefore suggested that the large diesel vehicles should regulate the fans. The goal of this study has therefore been to find how active diesel vehicles should be able to start and stop gallery fans at both intake and return air. In this paper different methods for activating fans are discussed. Then the best methods are chosen and tested in the mine. In this study we have found that changes of temperature is a cheap and effective method to start and stop cross cut fans in sublevel caving and radio signals seem to be an attractive system for start and stop of gallery fans. This work has been done in close collaboration between LKAB in Kiruna and the University of Luleå - Division of Electronics and Division of Mining and Rock Excavation. A reference group for the project has been established with ventilation experts from the mines, representatives for the local mine worker&apos;s unions and authorities from the local Governmental Inspection of the Workers Safety. VENTILATION SYSTEM STUDIED In the project the ventilation system at LKAB in Kiruna has been studied. The mining method used is sublevel caving with 9-13 m slice height. The air is heated winter time over ground by hot water heat exchanger. The main fans are pushing air down to a main distribution level along the 4000 m long and about 100 m wide orebody. From the distribution level, air is taken through shafts down to the sublevels, where it is pushed through the levels by local gallery fans on both intake and return side, see fig 1. The air ( ~ 8 m3/s) is moving freely through the gallery head. The cross cuts are ventilated with smaller fans, diameter 500 mm, and flexible duct, see fig 2. The aim of this study has been to study how to start and stop gallery- and cross fans and examine the environment when the fans are stopped . In Sweden there are no regulations telling that a minimum of air amount must be supplied. Instead the hygienic limits must be fullfilled.

Jan 1, 1981

By Michael Chender

Introduction Clearly, many problems confront the minerals industry today. Yet, at the same time, there is too much energy spent bemoaning the negative effects of difficult economic circumstances, low metals prices, and adverse government policies. These are factors that cannot be altered by individual mineral company reactions. In fact, as we look to the future, the only thing we can be certain of is that we will continue to be faced with uncertainty. Thus, an area that demands close scrutiny and that can significantly affect a company&apos;s performance in the future is the posture it adopts to deal with uncertainty. This paper looks at how strategies are developing to deal with this issue. It also examines some of the implications that implementing such strategies have for the role of the individual explorationist. Elements of strategy Whether mineral company strategies are based on diversifying or retrenching, on emphasizing primary production or downstream integration, there seems to be increasing agreement that in the current environment strategies must have several features. They need to be information-based - developed out of access to timely and complete data and analysis about proposed directions and competitor activity, rather than simply following a current fashion. They need to be flexible - adaptable in light of changes in the marketplace and an unpredictable industry. And they need to be cost-efficient - making the most of limited resources. Whether a company is looking for gold financing opportunities, acquiring polymetallic prospects, or doing grassroots exploration for diamonds, these three elements are increasingly essential. They not only allow the company to pursue its current goals most expeditiously, but also open it to hearing and using feedback in the most constructive way. The company can then improve or change strategy as it proceeds. And it can be best positioned to take advantage of opportunities as they arise. These elements of strategy place great emphasis on the skills of the individual. The need for critical intelligence and the reduced amount of capital available to manage are making it more obvious that exploration is a "people" business. This is in accordance with a general trend in many sectors of industrialized economies, reflecting the widely discussed shift from smokestack to information-based industries. Increasing the odds There is a direct connection between successfully implementing the approaches to strategy discussed above and encouraging and improving the quality of work of the individual explorationist. To illustrate the importance of this, some commonly quoted figures on the odds of discovery success can be used. These figures are arbitrary but illustrative. Assume that one out of 100 exploration prospects actually turns out to be a promising ore body, and that one out of 1000 becomes a mine. Based on our research, chances are the most of those

Jan 1, 1986