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By Harry M. Conger

Kaiser Steel Corporation's Eagle Mountain Mine is located in the Colorado Desert, 60 miles east of Indio, California. Concentrates from the mine are shipped by rail 164 miles to the company's steel mill at Fontana, and also to Longbeach, California for export. Temperatures are typical of the lower desert ranging from a high of 120 degrees in the summer to a low of 25 degrees in the winter. The average annual rainfall of about two inches comes mainly as cloud bursts during the summer months. From its inception, the Eagle Mountain Mine has had the problem of breaking its mine rock. Practices followed from 1949 until 1962 were very costly, did not produce uniformly good fragmentation, and were incapable of sustaining high production. During this period, every conventional type of explosive then in use was tried and found to be unsatisfactory for one reason or another. The first slurry test work at Eagle Mountain was started in 195E and finally by 1962, after having tried all the slurry mixtures then available including some "home made" formulas, a metallized slurry was perfected at the mine which overcame all of the disadvantages of former blasting methods.

Jan 1, 1965

By K. Thomson

The Mule Canyon gold deposit, located 14 miles ESE of Battle Mountain, Nevada, was discovered in 1986 as the result of a GFMC grass-roots exploration program. Drilling to date has identified six discrete orebodies which contain a demonstrated gold reserve of 8.487 million tons at an average grade of 0.136 oz/ton, totaling 1,152,000 ounces. Mineralization is associated with argillic alteration and silicification, localized along NNW trending high-angle faults within Miocene basaltic andesites. Trace element geochemistry at Mule Canyon is typical of upper level hot spring precious metal systems, displaying elevated Ag, As, Sb, Hg, and Se.

Jan 1, 1993

By C. J. Johnson, C. J. Bise

Introduction Coal extraction by continuous miners (CM) is currently the most common underground method in the US industry and accounts for slightly more than two-thirds of the nation's deep mining production (National Coal Association, 1987). Even if longwall mining should become more commonplace, it can proceed only after ventilation and access entries have been driven by CMs. Since an area of concern continues to be the effects of the dust generated on the health of mineworkers, this paper discusses the relationship between the elemental compositon of mining-generated airborne dust sampled from the immediate ventilation return of a CM and laboratory-generated dust derived from channel samples taken from the mines. There are several potential contributions of this type of study to the coal mining industry. First, after more fundamental knowledge of the causes of Coal Worker's Pneumoconiosis (CWP) is learned, the laboratory-generated respirable dust could be used to identify a potentially hazardous coal seam. Also, this study could possibly aid in understanding the fundamental causes of CWP by producing mining-simulated samples of coal dust that could be used in epidemiological studies. Further, assuming that there is no difference in the elemental composition of a drill-core sample and a channel sample from the same location, a mining company could predict a new mine's respirable dust elemental composition in the immediate ventilation return by using exploratory drill core samples of the roof, coal, and floor rock to prepare the laboratory dust. Ventilation engineers could then use engineering design and control measures during premine planning to reduce the incidence and severity of CWP by better ventilating the potentially hazardous coal seam. If this proper planning prevented any future changes to the ventilation equipment and mine design, much time and money could be saved. Scope of work To investigate the variability of the chemical characteris tics of respirable dust, airborne dust samples from eight underground coal mines located in the eastern and midwestern United States were collected with eight-stage Sierra Model 298 Marple cascade impactors, as well as 25 channel samples of mined material. Each channel sample was removed from the middle of the coal face before mining occurred. Sampling of the mining-generated dust was conducted by Lee (1986) by sampling the entire working sections, primarily for characterization purposes, to obtain information on the locational variability of dust characteristics. Research performed for this study used the elemental analyses of the mining-generated dusts he sampled in the immediate ventilation returns of CMs. The procedure that was used to produce the laboratory-generated respirable dust was based on the Hardgrove grindability test since it reflects the pulverizing characteristics of coal. This test was chosen for several additional reasons. First, it is repeatable and reproducible. A consistent amount of input energy is used as well as a specified size range of feed material to be crushed (the channel samples). Second, it is thought to generate secondary dust in a way similar to that of the crushing and grinding of the coal and rock as they pass through the arc-shaped cutting path of the CM's cutter head. The potential effect on dust generation by this secondary grinding mechanism may be at least as much as that produced by primary fragmentation, which is dust produced by the cutting action of the bit against the coal or rock (Roepke, 1984). Finally, the Hardgrove grindability test is well known and is used in the coal industry to guide mineral processing engineers in estimating the capacity of mills used to grind coal. One hypothesis of dust researchers in the Generic Technology Center for Respirable Dust is that the elemental as well as the physical characteristics of coal mine dust will make a difference in the incidence and severity of CWP. Coal mine dust is generated not only from coal, but also from any rock partings contained within the seam or any roof or floor material mined with the coal. Thus, coal mine dust may not have the same elemental characteristics as the coal being mined. Given that hypothesis, mixtures proportional to each thickness mined of roof, coal, and floor rock derived from the channel samples of the face areas from which the respirable dusts were generated by the CMs were used to produce the feed material that was pulverized in the Hardgrove machine.

Jan 1, 1989

By B. K. Mishra

This paper focuses on the use of a numerical tool known as the discrete element method (DEM) to study the motion of ball charge in ball mills (14-18 ft). DEM is employed to simulate the motion of individual balls. While doing so, the effect of liner design on the grinding performance of the mill is studied. Two important factors such as the configuration of the liner and the geometry of the lifting surfaces are correlated with the overall mill performance. An attempt is made to show the effectiveness of the lifter bars in transmitting power from the mill shell to the interior of the mill with particular emphasis to large diameter mills.

Jan 1, 1992

By G. A. Doyle

The White Pine Mine is the second-largest active underground copper mine in the United States, covering an area of approximately 13 square miles in the Upper Peninsula of Michigan. The mine operator intends to initiate in-stope solution mining by circulating a solution of mine water, sulfuric acid, and ferric iron through rubblized ore and recovering copper from solution. As planned, the solution would be retired in the mined-out stopes following completion of solution mining activities. Investigations into the fate of the retired solution mining fluid indicate that the solution, through time, will change from an acidic, metal-rich solution to a near-neutral, reducing solution containing much lower concentrations of metals. Investigations include reaction path modeling (EQ3/6) and laboratory and in-mine experiments. The combination of neutralization and reduction will result in precipitation of most metals, primarily as metallic sulfates, chlorides, and sulfides.

Jan 1, 1996

By A. Spearing

According to a 2000 NIOSH report, about 100 million rock anchors are installed annually in coal mines in the USA. Most coal mines have conditions that are conducive to corrosion of the rock anchor and ancillaries (such as plates), yet the effect of this on the performance of the anchors has not been adequately researched and its effects are not understood or quantified in the USA. There is considerable research into corrosion in civil engineering applications on surface and underground but the corrosion of coal mine rock anchors is not necessarily the same because: ? In underground civil structures, water ingress is usually stopped as part of the construction process. ? Many rock bolts in mines are only partially resin grouted leaving part of the reinforcing member exposed to corrosive conditions. All cable bolts in coal mines are only partially resin grouted. ? Even when mine bolts are fully grouted, shrinkage cracks occur and the rock stresses can change due to adjacent mining that can cause the resin column around the bolt to fracture further under external shear or tensile stresses. Most coal mines therefore have ideal conditions for bolt corrosion.

Jan 1, 2010

By S. A. Jeric

In-pit crushing and conveying of waste has been utilized in the mining industry for over 30 years. In recent years, innovations in crushing, conveying, and particularly waste and leach stacking technology have sparked a renewed interest in continuous haulage systems for large-scale open pit applications. A review of the advantages/disadvantages and operating techniques of crushers, feeders, conveyors, and stacking systems currently available is made. The paper examines some operations that are currently using large scale continuous haulage systems. Finally, a case study is presented that evaluates the application of a continuous waste haulage system in a large open pit mine in the Western United States, The case study includes a economic comparison with the existing truck haulage system.

Jan 1, 1997

A charge of the Research Council of the Society for Mining, Metallurgy and Exploration, Inc. (SME) is to ?? identify longer term research ideas/needs, that in the perception of the SME Research Council, could represent significant technology breakthroughs ?? (SME, n.d.). In 2008, the Council decided that instead of unilaterally developing a list of top priorities, it would involve the entire membership of SME in identifying the top priorities. Additionally, it decided to keep the list short. This paper describes the process and results from that exercise.

Jan 1, 2010

By R. J. Sweigard

Fine coal refuse is often pumped, as slurry, into surface impoundments as a means of permanent disposal. As the available volume is filled, the height of the embankments are frequently increased. Many times the additional embankment material is placed upon consolidated fine coal refuse. There has been some concern about the long-term effect of consolidation of this material at or above the liquid limit upon its shear strength. A laboratory investigation was performed using three different types of fine coal slurry taken from Central Appalachian coal preparation plants. The refuse was consolidated in 10-foot plexiglass columns under incremental amounts of surcharge loading. The incremental loads were designed to simulate the effect of increasing the height of a refuse embankment on top of the consolidating coal slurry. After the refuse in the columns had consolidated for several months, the columns were cut apart and triaxial tests were performed on both the consolidated material and unconsolidated material for comparison of their shear strength parameters.

Jan 1, 1997

By A. W. Fahrenwald

The gyratory mill shown in Figures I and II is a ball mill in every sense of the term, in that the grinding media are balls. The media container, called the shell, is of the form of a shallow cylindrical tank whose position is with axis vertical The mechanism of the mill is designed to swing the shell in a circular path of small radius and, at the same time, to hold the shell in a position of constant orientation, i.e., the motion of the shell is such that every point on the shell surface -- bottom, wall and cover--travels in a perfect (horizontal) circle. The gyratory mill is definitely not a centrifugal ball mill. The balls do not, individually Qr in mass, travel in a circular path. Each ball, under heavy pressure from all directions, develops a sphere, or zone, of activity. Particles entering this sphere are crushed by impact. The gyratory ball mill, unlike the conventional tumbling mill, does not have, and is cursed by, a "critical speed". The speed of gyration, and in turn the power drawn by the mill--and ball potency--is limited only by the mechanical en- durance of the machine parts.

Jan 1, 1959

By P. Oghazi

It is possible to have traceability in the mining industry, by parameters and signatures like particle mineralogy, mineral association, texture and mineral liberation. The study is on an apatite-iron ore deposit at Malmberget, Sweden, and characterizes an ore body both mineralogically and texturally in a quantitative manner by using analytical methods like optical microscopy, microprobe (EMPA) and an automatic SEM based system, Particle Texture Analysis (PTA). The mineralogy was evaluated by PTA and characterized by modal mineralogy, mineral liberation and mineral associations. Magnetite has a simple outline and straight grain boundaries and the gangue minerals have a finer particle size with a more complicated texture. The PTA analysis also shows that apatite is associated to magnetite as mixed particles, while smaller grains of magnetite are inclusions in feldspar. Result from particle texture analysis shows that there is a connection which link to the mine-to-mill context, and it may be used to create traceability. This link is not the associations of the main ore mineral magnetite, nor the modal mineralogy. Instead, it is the mineral associations of contaminating minerals (apatite and feldspar) that appear to be most promising since they survive from mine to mill. The modal mineralogy may be used to understand how contaminated minerals break into or out of particles size fraction during grinding.

Jan 1, 2010

By James F. Archibald, Ferri Hassani, Jacques Nantel, David O. DeGagné

Operators depend upon the success of backfilling programs to ensure that mine activities run continuously (Archibald et al, 1993) where backfilling is an integral part of the mining cycle. In order to ensure that the backfill is prepared and delivered to the stope possessing the required engineering properties, as designed, and that the backfilling process is safe, mine operators at all stages of the backfilling system must be adequately trained for their tasks and be aware of how their work affects other backfilling stages, both up- and down-stream of their station. Mine operator training is primarily based on learning on-the-job from experienced supervisors or training personnel. Classroom training and the availability of reference manuals are less common. While in use by many industries for some time now, computer-based training (CBT) is becoming more readily accepted by the mining industry for a wide variety of training. It is not intended to replace on-the-job training, but to augment it. CBT offers many advantages to enhance operator learning by utilizing multimedia presentations, interactions and on-line testing to teach complex concepts and relationships. Discussions with many operations revealed that there is an industry need for a backfill guide for frontline operator training and as a reference manual for operators and mine engineers. Sponsored by the mining industry and the CIM, "Mine Backfill, An Operator's Guide" has been developed by the Departments of Mining Engineering at Queen's University and McGill University to fulfil this need. "Mine Backfill, An Operator's Guide" is an interactive multimedia package that incorporates high quality colour images, animations, sound, and video with text to review the main backfill methods employed in Canada, including hydraulic/slurry, paste and rock fill. The Guide is divided into training and reference primer sections. When in training mode, the operator is guided through a presentation of common mining and backfill practices and technologies so that he/she may become more familiar with different aspects of backfill processes. To ensure that key concepts have been learned during training, the operator will be tested after each section using a series of multiple choice and true/false questions. When in reference mode, alternatively, the operator may browse through the information in a more detailed and independent fashion through a series of interactive menus. The Guide focuses on the following main topics: resources, surface preparation, distribution, stope activities, health and safety, and quality control. Special features included in the Operator's Guide are a Buyer's Guide, a Trouble Shooting Guide, and an interactive glossary of backfill and mining terms. Concepts in interactive and computer-based learning are also reviewed in this paper.

Jan 1, 2001

By T. J. Morris

"From November 2014 through September 2016, Westmoreland’s Coal Valley Mine utilized a Marion 7450 electric walking dragline to extract 1.2 million tonnes of a vertically-dipping, 52-meter wide, fault-thickened seam, beneath a conventionally-excavated pit bottom. Mine planning and operational hurdles encountered throughout a kilometer of mined strike length included mitigating highwall instability in both hanging and footwall slopes, water management, and end-of-life machine reliability and maintenance. The most substantial challenge has been the depressed global coal market. However, the successful application of this mining method significantly aided the overall cost of production at the site. The valuable experience gained from this project will be extended to future mining areas where this technique can be similarly applied. INTRODUCTION Coal Valley Mine is located approximately 220 kilometers southwest of Edmonton, Alberta, Canada, in the foothills of the Rocky Mountains. Since commercial production began in 1978, more than 84 million clean tonnes of coal has been produced and sold domestically as well as exported overseas for power generation. While the existing processing plant has a nameplate capacity of 4 million tonnes per year, the site has operated at a 2 million tonne rate since 2015 due to depressed export markets. Westmoreland acquired the mine as part of its purchase of Sherritt Coal Operations in April 2014. The mine operates 24 hours a day, 7 days a week, with an IUOE workforce of 261. GEOLOGICAL SETTING The geology of the Yellowhead Tower mining area differs significantly from previous mining areas at Coal Valley. The Mynheer coal seam discussed herein consists of steeply dipping, highly-sheared, thrust-faulted, and heterogeneous coal pods. Deep set, southwest striking thrust faults were the likely mechanism for the podding and have resulted in overturned, rolled and highly sheared seams with zone thicknesses of up to 65 meters.The hanging wall is characterized by soft bentonitic mudstones and siltstones, overlain by massive competent sandstone. The footwall is defined by a hard volcanic tuff, interbedded with thin, sporadic coal seams. The sandstone above and volcanic tuff below constrained the faulting system within this zone, enabling the mass podding that has afforded the opportunity for large-scale mining."

Jan 1, 2017

By Chulho C. Song, Liam Coleman

Alkaline pressure oxidation (POX) is an oxidative pre-treatment option that is commercially used for high-carbonate sulfidic gold ores. The high carbonate grades within the feed ore shifts the ideal operating pH to a basic regime. Compared with acidic POX, alkaline POX typically requires additional steam input due to a lower sulfur oxidation load and a high rate of in-situ carbon dioxide generation that needs to be vented along with steam. The cost of this steam addition is the largest differentiator between acid POX operation and alkaline POX from a cost comparison. However, alkaline POX can offset these costs through reduced acid usage for pre-acidulation and decreased alkali reagent consumption for subsequent neutralization. This paper reviews the specific operating cost impacts of acid/base consumption between alkaline and acidic POX with ores which require pre-acidulation, the overall economics of alkaline POX, and the regimes in which alkaline POX is economically favorable. The findings aim to guide industry professionals in making informed decisions for alkaline POX adoption by providing a summary view of its operational benefits and costs, contributing to the development of cost-effective and sustainable gold ore processing techniques.

Feb 1, 2025

By Allison L. Hornbaker

Millions of years ago, in late Cretaceous time before man existed on Earth, tremendous orogenic forces began to change the face of the western part of the North American Continent. Catastrophic events marked by huge uplifts of thousands of square miles in the Cordilleran Belt, some of which are barely discernible in the geologic record, were accompanied by long periods of batholithic intrusions and volcanic eruptions. These events produced the great Rocky Mountain systems, which were at the time even higher and more rugged than they are today. Such activity continued into Tertiary time, and during the Pliocene and Pleistocene periods millions of tons of volcanic ash were hurled skyward by explosive volcanic activity and carried by the westerly winds to the east where it settled out of the atmosphere and deposited over thousands of square miles of the high plains. Unusually heavy rains, probably caused in part by the volcanic activity itself, together with high winds, reworked and redeposited the freshly fallen ash into lakes and depressions of varying sizes and shapes. Subsequent deposits of sand, gravel and loess covered the deposits of volcanic ash, preserving them in the condition in which they are found today. In many places erosion has cut through the sand, gravel, loess, and volcanic ash so that in favorable localities on hillsides and gullies, exposures of volcanic ash can be seen interbedded with sand and gravel.

Jan 1, 1970

By Carl F. Austin

The subject of strata control in mining can be approached from both static or loading concepts or from dynamic or impulsive loading concepts. The fracture process itself appears to be primarily a dynamic process as is the gross creation of fractures through the use of impact, stress wave passage or in more general terms, the use of explosives. This paper presents experimental results which indicate that the understanding of the fracture behavior of rock that has been, established in the open literature is not always appropriate. In particular, the results of this experimental program have shown very interesting differences between the formation of fractures in rock and the formation of fractures in other materials such as metals and plastics which are often used as models for rock behavior studies Fracture patterns and causes of dynamic fracturing in various rock and artificial materials are presented.

Jan 1, 1965

By James R. Arnold

Over the past few years several commercial wetting agents and drying aids have been tested in the lab and in the plant at Gold Fields Mining's operations at Mesquite and Ortiz. The major goal was to increase recovery with these surfactants by improving the permeability of the pad and increasing the rate of penetration through the rock.

Jan 1, 1988

By E. A. Noble

In the Western Coal Region, successful reclamation of surface-mined areas includes the protection of groundwater sources. To accomplish this, a complete understanding of the geohydrology of the affected area is imperative. Successful mine design also calls for careful attention to geohydrology. Because the Western Coal Region is semi-arid land used mainly for farming and grazing, groundwater is a particularly sensitive topic. It is especially sensitive where the lignite scheduled for mining is itself the aquifer supplying the farms and ranches. Such is the case throughout much of the Western Coal Region, particularly where there are no near-surface sand and gravel aquifers that are commonly found in the glaciated portions of the Region. Just as mining can adversely affect groundwater supply, so can groundwater adversely affect mining. Mine flooding and highwall instability are examples of this. But, mine operators must realize that procedures they use to remedy geohydrologically-related mining problems can have a dramatic effect upon ground- water conditions in areas adjacent to the mine. A logical precaution is to require the acquisition of complete baseline data prior to making the first cut. We recommend that the mining plan not only incorporate the reclamation plan, but that they be developed as one plan.

Jan 1, 1976

By C. M. Walck

The Rosebud district is located in the Kamma Mountains, southeast of the townsite of Sulphur, Nevada. Since discovery in 1989, LAC Minerals, in joint venture with Equinox Resources, has delineated a resource containing approximately 570,000 ounces of gold and 5,500,000 ounces of silver. The deposit is of the volcanic-hosted epithermal quartz-sericite type. Mineralization occurs in tabular zones in and along the hanging wall of the South Ridge fault, and in cross-cutting high-angle structures. Multiple stages of discontinuous stockwork gold-and silver-bearing quartz-calcite-clay veins cut variably clay-altered, silicified, and sericitized rhyolitic Miocene volcanic rocks.

Jan 1, 1993

By R. L. Lewis

A simple method for estimating the steady-state water quality of a pit lake is presented. The steady-state concentration of a conservative chemical constituent in a pit lake is shown to be a simple function of inflow rate, evaporation rate, and inflow concentration. An analytical method is presented for estimating the equilibrium ground water inflow rate for use in water quality predictions. The time required to reach chemical steady-state is estimated using an iterative mass balance model. Mine operators should find the methodology useful for planning and screening-level regulatory applications where conservative estimates of pit lake water quality are desirable.

Jan 1, 1998