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By W. D. Macleod

This paper describes a mineral dressing process for the upgrading of tin ores. The process described is called 'agglomeration' and. is similar in many respects to flotation. Many variables have been examined experimentally both on batch and continuous operations and are reported upon herein... Using a Mt. Pleasant tin ore, assaying 0.5% Sn, an upgrading to 8% Sn, with a recovery of 95% could be obtained by this process.

Jan 1, 1966

By Mary E. Learmont

Grinding with steel media adversely affects the flotation response of galena. Electrochemical measurements, flotation tests, and AES, XPS, and STEM examinations were employed to identify interactions between galena and mild steel. Iron oxide, hydroxide, or sulfate species that formed on the galena surface upon contact with mild steel decreased its floatability, with the time of contact and aeration condition affecting the severity of the flotation depression.. Parallel tests performed with an active metal, magnesium, indicated that floatability was also affected by the presence of a surface coating involving lead species.

Jan 1, 1984

By Ramon B. Santos

The Atlas Concentrator, reputedly the largest in the Far East today, is located on the island of Cebu in the Republic of the Philippines. It started operation on a 4000 TPD capacity in 1955. An expansion program, coupled with significant improvements both in the Crushing Plant and the Mil, made the Atlas Concentrator what it is today, treating about 14,000 tons of ore per day at a comparatively low cost of about $0.50 per ton treated. The Atlas Copper Mine is at present mainly an open pit operation, with ore supplied from two pits (Lutopan and Biga) north of the Concen¬trator. Development of an Underground Mine, situated on the main ore body at Lutopan, which will be a block caving operation, has been underway since 1963, and this underground mining operation is expected to b e in full production by the latter part of 1966.

Jan 1, 1966

By A. E. Sears

The intent of geomorphic landform design is to mimic the function of the natural landscape. In a surface mine reclamation application, geomorphic landform design has the potential to mitigate stream loss. This research quantified features of reference landforms and performed computer modeling of a conceptual valley-fill design using geomorphic landform principles. A design was created using published design parameters with a software design tool (Carlson Natural Regrade with GeoFluv). Three additional designs, incorporating field-obtained regional geomorphic landform parameters, were completed and resulted in a geomorphic landform design specific to southern West Virginia. This work illustrates the importance of field determination of the ridge to head-of-channel input and drainage density parameters. Values of ridge to head-of-channel distance measured in this study were consistently an order of magnitude greater than software recommended values (SRV); SRV = 24 m (80 ft) versus field= 220 m (720 ft). Similarly, for the drainage density parameter, the software recommended range is 6 to 9 km-1 (80-120 ft/ac). The field measurements for central Appalachia quantified the drainage density to range from 5 to 5.3 km-1 (67-70 ft/ac). This affects Appalachian valley-fill stream construction by making the stream lengths shorter and the land slopes steeper with straighter headwater channels compared with areas in the southwestern United States. While the application of geomorphic landform design to surface mine sites presents challenges, this work provides support for future applications.

By Michael Wortley

Metso?s Process Technology and Innovation group is a world leader in mineral processing consulting. A significant amount of this consulting work involves process integration and optimization (PIO) studies, which include investigating the effects of drill-and-blast design and implementation on downstream processing. Critical to these studies is the ability to track specific ore into, and through, the plant. To increase the accuracy of this ore tracking, Metso Process Technology and Innovation (PTI) developed a system to track ore using a radio frequency identification (RFID) transponders technology designed to allow tracking of ore from its source through blasting, run-of-mine (ROM) pads, crushers, intermediate stockpiles and, finally, into the concentrator. The system is called SmartTag. Since its commercialization in 2007, SmartTag has been used in the majority of PTI?s consulting projects, and several permanent systems have been installed worldwide.

Jan 1, 2012

By S. P. Taite, A. R. Charest, P. D. Lewis

The El Sauzal deposit is a classic, high sulfidation, epithermal gold system located in southwestern Chihuahua State, Mexico. The prospect was discovered by a Francisco Gold Corp. geologist in1995. El Sauzal was encountered as a result of an extensive grass-root exploration program in the rugged, dissected volcanic terrains of the Sierra Madre Occidental, around the historical Batopilas Silver Camp. At El Sauzal, high grade gold is hosted within a series of more permeable, low-dipping, lithic and fine-grained dacitic rocks of early Tertiary age. The mineralization appears to be both structurally and lithologically controlled. The alteration characteristics are typical of a high sulfidation system including kaolinite, illite, alunite, dickite and pyrophyllite. The deposit’s gold distribution, as recorded from drill-hole data and surface samples, varies from 0.2 to 650.0 g/t. The estimated geological resource, as calculated from an independent study completed in 1998, was 3.0 million oz @ 2.03 g/t including a minable reserve of1.8 million oz @ 3.3 g/t.

Jan 1, 2004

By Terry Owen

Not since 1917 has a foreign company developed a standalone, grass roots gold mine in Russia. With Russia's political changes of the late 1980s, development of mineral prospects once again beckons foreign investors. Cyprus Amax's interest in Russia began before the mid-1991 breakup of the former Soviet Union. In 1990, Cyprus Amax began searching for such an opportunity. Early this year, production will begin at the Kubaka gold project located in the Russian Far East, near the Arctic Circle. The Kubaka project is a 1.75-kt/d (1,930-stpd) open-pit operation that will produce more than 9.3 t/a (300,000 oz/year) of gold. Identifying Russian mining opportunities In late 1990, the first Cyprus Amax people travelled to Russia. The trip was to determine the potential for western firms to develop profitable mines. This encouraging visit suggested that Cyprus Amax focus on the Russian Far East with its mineral riches and its easier access to the United States. The company's initial efforts thus focused on working with the Soviet Union's Northeast Geologic Expedition, the then government agency for exploration and geology in Russia's Far East. After the breakup of the Soviet Union, Cyprus Amax continued working with the same people, but they now represented new independent, nongovernmental entities. For three years, Cyprus Amax investigated numerous deposits. This resulted in the identification of two properties of significant interest, one of which was Kubaka. Location Kubaka is located in the Northern Evensk District of the Magadan Oblast in the Russian Far East. This is an area east of Siberia. The project is situated in a mountainous area of the Kolyma Range, about 300 km (985 miles) south of the Arctic Circle. It is 285 km (180 miles) north of the fishing village of Evensk and 380 km (235 miles) northeast of the silver-mining town Omsukchan. The site is 950 km (590 miles) northeast of the regional capital city of Magadan. Magadan, the political and economic center of the Oblast, has a population of about 150,000 people. It is served by a year-round deep-water port (with icebreaker assist) and an international airport with service to Moscow and Anchorage, AK. Access to the Magadan region

Jan 1, 1997

By V. E. Housman

EPA's Mining Waste Section within the Office of Solid Waste is continuing to collect and analyze information on mining waste management practices. Starting in 1991, the Mining Waste Section has continued to conduct site visits and prepare case study reports on the waste generation and management practices of operating mines. In choosing sites to study, a reasonable attempt was made to provide diversity in mining commodity types, geographic regions, geology, climate, and environment. To date, EPA has visited the following mines: Asarco Troy (copper) in Montana, Newmont Rain in Nevada (gold), Cyprus Thompson Creek (molybdenum) in Idaho, LTV Steel (iron) in Minnesota, Phelps Dodge Morenci (copper) in Arizona, Doe Run Fletcher (lead) in Missouri, Brewer (gold) in South Carolina, IMC Four Corners (phosphate) .in Florida, Pennzoil Culberson (sulfur) in Texas, Nerco Cripple Creek (gold) in Colorado, Copper Range White Pine (copper) in Michigan, Magma San Manuel (copper) in Arizona, Colosseum (gold) in California, and several gold placer mines in Alaska, including the Valdez Creek Mine. EPA has prepared a case study report on each facility. The mine operators were provided an opportunity to comment on their respective site visit report and their comments have been included in' each respective report. These site visit reports have in turn been incorporated into technical resource documents which provide a detailed description of each mining sector. EPA is currently reviewing the technical resource documents and plans to release the documents in the Spring of 1994.

Jan 1, 1994

By Yuting Xue, Mark Van Dyke, Joe Wickline

The understanding of coal mine roof lithology is a critical component in the determination of engineering solutions for roof control. Coreholes were the first technology available to determine lithology of the roof in reserve areas, but coreholes are typically drilled 500–2,500 ft apart due to their cost and sometimes reach more than $125,000 dollars per hole, depending on mine conditions. The next method developed to bridge this gap was the fiber-optic scope which is utilized in the roof at the faces of underground development. High-end fiber-optic scopes can also be costly (20,000–40,000 dollars) but are more affordable than drilling a corehole, and the information can be processed immediately to make quick roof support determinations. The fiberscope can be operated wherever a roof bolter can drill a hole, and there are no restrictions related to property owners, proximity to streams, elevation changes, etc. The latest borescoping method utilized by mining companies is the use of videoscopes. Videoscopes and all borescopes in general are limited by the lengths of the scope and the length of the borehole drilled in the mine. Videoscopes have the advantage of being able to record video while examining the roof lithology. The information can be recorded quickly underground and then be examined on the surface which allows anyone to capture the video so that a geologist can make lithology descriptions without ever going underground. In the past, videoscopes had limited resolution, a short battery life, were fragile and were relatively costly. As technology progresses, videoscopes have become more affordable, have increased battery life, and offer enhanced 1080p resolution. With the broader availability of affordable videoscopes, videoscopes can be more readily used in various mine environments at every active section underground. This paper will discuss the types of videoscopes available, the features that will aid in lithology description/identification, the deployment methods pertaining to supplemental roof support recommendations, and an advanced methodology to enhance accuracy in understanding roof lithology.

Feb 1, 2025

By James F. McConnell

Federal and State sulfur oxide emission and ambient air quality regulations have been implemented to fulfill the requirements of the Federal Clean Air Act Amendments of 1970. Primary and secondary air quality standards have been established at levels considered necessary to assure the protection of the health and welfare of the public. Standards of performance under this Act have been established to control the rate of sulfur oxide emissions from individual sources so as to protect and to improve the quality of the Nation's air. The new source standards of performance were made rigorous for large coal burning stationary sources. This has had a severe impact on the electric utilities that operate the coal fired steam electric plants which are the largest consumers of the Nation's coal production. States have taken different approaches in State Implementation Plans (SIPS) as approved by the Federal Environmental Protection Agency. Some states, such as Pennsylvania, have chosen to permit moderate SO2 emission rates from existing sources which are not in critical air basins. All are required to meet primary and secondary air quality standards and to limit sulfur oxide emissions from new large stationary sources to a minimum of 1.2 LBS of S02/MMBTU fired. This re- quires a fuel sulfur percentage of about 0.7 for a 12,000 BTU/lb coal. In an effort to develop strategies and technologies to conform to performance standards while continuing and hopefully expanding the utilization of the Nation's coal supply, the electric utilities, the Federal and State regulatory agencies, and other industries and government agencies are considering several alternatives. 1. Natural low sulfur coal 2. Flue gas desulfurization - (FGD) non-regenerative and regenerative 3. Coal gasification 4. Liquefaction and solvent refined coal 5. Fluidized bed combustion 6. Chemical coal cleaning 7. Physical coal cleaning Of these options, only the first and the last can be considered to be widely used in full commercial practice at this time. FGD has certainly demonstrated technical and operating feasibility and is close to being in full commercial practice but it remains to be seen if the large systems under construction are economically and environmentally optimum.

Jan 1, 1975

By L. Valentik

Many attempts have been made during the last forty years to evaluate the performance of gravity separation equipment, that is, the effectiveness with which light and heavy particles are separated. The most comprehensive treatment of the subject was made at the 1st International Conference on Coal Preparation held in Paris (1950) by Cerchar. The methods suggested by the Conference were accepted and very widely used in the last 25 years. This paper discusses an improved method of evaluation in the light of the now accepted standard presentation. The float and sink analysis of the product is presented on a Gaussian distribution curve, resulting in an easier visualization of the inherent difficulties of separation. The ogives of the distribution curve are then plotted, giving a quantitative measure of the deviation from perfect separation as an error distance instead of an error area. Illustrations of the new method are given both for gravel and for coal preparation, but the concept is valid and applicable to other types of minerals which are separated by gravity methods.

Jan 1, 1968

By Patricia Curtis Petty

Thirty years ago, the appearance of a female mining engineer, geologist or miner in a company, union or mine environment would have been unthought of, unwelcomed and violently opposed. Twenty years ago, the intellectual perception of the news that women were interested in becoming mining engineers, geologists and miners had been accepted by the industry-but no one wanted to be the first to hire one of these exotic creatures. Ten years ago, those who had been most vehemently opposed to the philosophical idea of women working in these areas were faced with competent, productive engineers, geologists and miners-who only incidentally happened to be women-and began hiring them. Historically, of course, one can always find the isolated individual who worked in these areas-the first female graduate of the Colorado School of Mines with a mining engineering degree graduated in 1903-but the concept of woman as professional engineer was very slow in arriving in the United States. The few who worked as miners generally worked in small family enterprises, such as some of the coal mines in both Eastern and Western United States. Others accompanied husbands or sons into wilderness areas searching for gold and other precious metals.

Jan 1, 1984

By S. Angioletti

This paper addresses strategic investment decisions when they are nested in a project development format where each project is implemented in phases and each phase is approved to move on to the next phase only if certain technical and economic requirements are met. This configuration is sometimes referred to as a ?Project Portfolio?. Mining companies maintain project portfolios in their exploration investment plan. This study proposes a procedure to best manage an exploration project portfolio including technical and economic uncertainties. The procedure may support decision makers in a simple and intuitive way, while maintaining the rigor and precision required by the rather large amount of financial resources typically called for by mining projects. The procedure was tested in a real case study of a gold mining company and its exploration projects portfolio. The procedure uses the following approaches: i) investment valuation methods under technical and market uncertainties based on Option Pricing Model, Real Option Theory and Option Space; ii) portfolio management and Stage Gate®1 method; iii) Monte Carlo simulation.

Jan 1, 2010

By L. G. Austin

The model originally proposed by Austin, et al., has been modified in the light of further investigation of the breakage laws in SAG milling. The model uses a fully-mixed reactor for short L/D mills and calculates the breakage of small particles by the nipping action of balls and pebbles. The autogenous self-breakage of larger lumps is treated as an effective means of fast breaking rock and much slower breaking rock. Experiments show that fast autogenous breakage can be treated as a first-order breakage with an overall specific breakage rate which incorporates fracture and chipping. Similarly, slow breakage incorporates fracture and abrasion. Autogenous breakage is cushioned by the accumulation of fine material. Simulation results are compared to results from tests in a 2 m diameter continuous pilot-scale SAG mill. Future work is discussed.

Jan 1, 1985

By H. Huang, R. N. Gow

"EH-pH diagrams are useful tools in understanding how mineral surfaces react in solution and particularly how aqueous conditions can be changed to enhance mineral leaching processes. Successful application of these diagrams, however, requires that several considerations be kept in mind to prevent what had been termed as “gross errors” in their calculation and use. In this paper, the aqueous Cu-S system is used as the basis for explaining the mass-balanced method of calculating EH-pH diagrams with the STABCAL thermodynamic equilibrium software. A breakdown of the Gibbs’ Phase Rule and how it is used in STABCAL to modify the diagrams is included. The methodology was applied to the aqueous Cu-As-S system, and resulting diagrams were compared against examples of those generated using the predominant-ion method. The complexity of such diagrams increases with every additional component, and competition between species becomes more apparent, as can be seen by curvature in the resulting mass-balanced diagrams. The complete diagram for enargite (Cu3AsS4) is shown. It compares well with spectroelectrochemical measurements from Raman spectroscopy and cyclic voltammetry studies.IntroductionInnovation in the field of processing arsenicbearing copper ores has been of particular interest. Copper arsenic sulfosalt minerals such as enargite (Cu3AsS4) and tennanite (Cu12As4S13) are now frequently prevalent in ore bodies as the oxide and easily leachable sulfides become harder to find. These minerals, unless pretreated somehow, concentrate in copper sulfide flotation processes, in turn concentrating the arsenic levels. Increasing environmental restrictions on arsenic content for smelters makes the hydrometallurgical processing of these concentrates more favorable. While enargite is considered one of the more refractory copper sulfides, more so than chalcopyrite (CuFeS2), there are still several methods, both industrially proven and in development, that are capable of processing these ore types. Alkaline sulfide leaching can be used as a pretreatment method to solubilize arsenic selectively (Delfini et al., 2003; Anderson and Twidwell, 2008; Tongamp, Takasaki and Shibayama, 2010a, 2010b), or the entire metal content can be leached using acid-type leaches such as acidified ferric sulfate (Dutrizac, 1981; Hackl et al., 1995; Klauber, 2008), or the chloride assisted, CESL (McDonald and Muir, 2007) or nitrogen species catalyzed (Anderson, 2003) processes can be used.As development of these leaching technologies proceed, it is also important to develop an understanding of the mineral thermodynamics. To date, there are numerous studies on the Cu-Fe-S-H2O system, particularly as it relates to chalcopyrite leaching, yet few studies have done on the Cu-As-S-H2O system. Computer-generated EH-pH diagrams have been employed to illustrate the importance of thermodynamic calculations in providing insight into such a system."

Jan 1, 2016

By R. Mensah-Biney

The kinetics of gold-bromide loading onto activated carbon has been investigated in a batch stirred reactor. The amount of gold adsorbed by the carbon was correlated with time based on a second-order equation. The rate constant for gold-bromide species onto activated carbon ranged from 0.27 to 1.2 x 10-3 (kg/t)-l(min)-l from a solution containing 25 ppm of Au, with 0.8 g carbon per liter of solution at 30° C. The equilibrium saturation capacity (Q.) was 36±3.0 kg/t from the same system. The rate of loading increased with decreasing particle size, decreasing pH, increasing temperature, and decreasing concentration of gold in solution. The calculated activation energy E. was 8.8 kcal/mole, significantly higher than those reported for physical adsorption. The equilibrium saturation capacity (Q.) increased with increasing concentration of gold in solution, but was independent of other variables such as temperature, agitation speed, particle size and pH. These rate constants and equilibrium saturation capacity for the gold-bromide species are higher than those reported for the gold-cyanide systems.

Jan 1, 1996

By John Murray, Daniel Ebin, Robert Gould, Yiming Sun, Lizan Gilbert

The Atlanta Plane Train Tunnel West Extension is being constructed at Hartsfield-Jackson Atlanta International Airport using the Sequential Excavation Method (SEM). The tunnel has shallow ground cover and mixed-face conditions and passes underneath the SkyTrain and MARTA stations and airport terminal buildings. It includes a twin tube Bifurcation with a span of over 45 feet and ground cover of 12 feet. A flat roof is being constructed at the Bifurcation to maximize rock cover and minimize surface settlements. This paper focuses on design and construction challenges for the Bifurcation and tunneling beneath the world’s busiest airport, while minimizing impacts to operations.

Dec 1, 2022

By R. Addison

This is the story of the Carlton Mill. But first-a little geography. For those who do not know where the Carlton Mill is, or, perhaps, have only a vague idea, its location is indicated in Figure 1. The plant is situated on the road between the two old mining towns of Cripple Creek and Victor, 10 the west of Colorado Springs. From Denver, it's about 110 miles by road. The story of the Carlton Mill began with the discovery of gold at Cripple Creek in 1890. This discovery set off a major boom such that, by the turn of the century, there were 450 separate operating mines in the district. Gold production boomed early and declined rather rapidly as indicated by the graph in Figure 2. Significant factors affecting production are shown on the graph-the raising of the gold price in 1934 from $20.67 to $35.00 per ounce and the government executive order L-208 in 1942 requiring the closure of all gold mines.

Jan 1, 1983

By Carlton H. Baab

In June, 1981 the Electric Power Research Institute (EPRI) issued a report titled "Control Systems in Coal Preparation Plants" to determine the status of instrumentation and automation systems in the coal preparation industry. EPRI concluded that the control systems presently being employed in the U.S. coal preparation plants "are relatively primitive compared with those in other mineral processing industries; and analytical instrumentation is virtually non-existent". Until recently, clean coal has had a low selling price and satisfying the purchasers' specifications required only minimum cleaning. However, it is becoming more apparent that the increases in coalfired utility power plants forced outage rates are relative to the deterioration in the quality of fired coal. Utility companies are becoming aware of the economic value of reducing the variability of ash, moisture and sulfur in steam coal purchase orders. New contracts are currently being negotiated between electric utilities and coal producers that include provisions for increased penalties if the product does not meet specifications. With tighter specifications on the quality of steam coal, interest is increasing in more sophisticated control systems. One type of device that is currently assisting the preparation plant operator optimize and control the coal cleaning process is nuclear based instrumentation. Nuclear instrumentation includes methods for measuring weight, level, and density as well as for performing elemental analysis on coal. This paper discusses the various types and applications of nuclear instrumentation currently in use in the coal preparation industry.

Jan 1, 1983

By Zainab Nasrullah, MontanaFrank Agyemang, Mehran Sadat, Richard LaDouceur

Rare earth elements (REEs) are valuable for various modern technological applications, including metallurgy, machine building, radio electronics, instrument engineering, nuclear engineering, and manufacturing. The extraction and separa-tion of rare earth elements (REEs) from their complex ores is challenging due to their distinct physical and chemical properties, contributing to their market scarcity. At present, REE recovery utilizes traditional pyro- or hydrometallurgi-cal processes. The overall process in the recovery and sepa-ration of individual elements from complex REE systems suffers from high energy demands and the use of many haz-ardous chemicals that negatively impact the environment. With the growing trend toward a circular economy aim-ing to balance sustainability, efficiency, and environmental impacts, this research is focused on using deep eutectic sol-vents (DESs): a combination of a quaternary salt: Choline Chloride and five organic acids: Oxalic Acid, Urea, and Ethylene Glycol, Lactic acid and Glycerol for the selective leaching of REEs from their complex ore which is proven to be green, selective, non-toxic, biodegradable, and cheap. The effects of different DESs and leaching time on the REE leaching efficiency were determined, and the optimum DES media were found to be Oxaline and Lactic Acid at which a leaching efficiency of 25% and 15% was achieved at 80°C respectively for cerium.

Feb 1, 2025