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By R. J. Visintainer, J. M. Furlan

"Due to the time-consuming nature of froth testing in a laboratory environment, practical limitations require the development of a method of applying a single set of performance test data (Visintainer and Whitlock, 2012) obtained for a single froth pump at a given speed to a range of froth pump speeds and sizes, % air content and liquid viscosities. Head, efficiency and flow all vary as functions of both liquid viscosity and air content. As such, it is necessary to develop a technique that can be used to interpolate from existing test data in order to predict froth performance for pumps of various sizes running at variable speeds. Details of the technique developed in order to achieve this goal, as well as the insights gained from analysis of the resulting regressions, are discussed. Additionally, comparisons are made between the performance predictions of this test-derived method and those of the Hydraulic Institute standard for the effects of liquid viscosity on centrifugal pump performance (ANSI, 2010).IntroductionPump performance data (Visintainer and Whitlock, 2012) has been collected for a froth pump using an experimental loop outfitted with an array of pressure transducers, mass flow meters, an inverted U-loop, magnetic flow meter and an assortment of other instrumentation. Experiments were performed on pure water, water and air, pure corn syrup, and corn syrup and air. Data was obtained for % air contents of 0-30% and viscosities of 1- 15,000 cSt at eight specific valve positions (eight different flows as a percentage of best efficiency flow points) and the viscosity was changed by allowing the system temperature to increase during testing. The test pump is a 710-mm diameter impeller, GIW HVF, open shrouded, vented design that has its discharge axis oriented at 45° upward from the horizontal. A schematic diagram of the froth pump test loop can be seen in Fig. 1."

Jan 1, 2015

By R. Kahrger

This paper is written to convey the latest developments in compact bucket wheel excavators (BWE's) operating in medium-hard rock and will serve to indicate that BWE and compact machines in particular do in fact have application in materials other than loose sandy soils and soft rock. A recently run extensive three month field test in hard marl, which was previously considered too hard and difficult to be handled by a BWE, is used as an example to explain some of the design requirements and problems associated with digging harder materials.

Jan 1, 1990

By J. S. Gardner

Fortunately, few mining professionals have dealt with what all mining professionals fear---a mine disaster. Unfortunately, many have dealt with ?accidents? which may or may not claim lives but nevertheless rise to the level of a ?disaster? given the fallout of liability and litigation in today?s society.1 The undersigned authors published an article some ten years ago regarding crisis management2 based upon their collective first-hand experiences in actual disasters to that point in history. Unfortunately, disasters have occurred since that time, prompting legislation, and a fresh analysis and expansion of those basic principles is certainly in order. Without question, no two disasters are ever alike, yet general guidelines for forming an effective plan of action can be formulated?and if a mining operation is to have any chance of survival after a disaster, such a plan is vital. The primary concern as any disaster evolves remains as stated a 2003 SME article3--the protection of human life. From that point, the focus moves to any assistance that may be needed given the magnitude of the situation. Permeating throughout this process is "damage control." The first step in dealing with a disaster, however, begins long before any threat of danger arises?formulation and implementation of an Emergency Response Plan.

Feb 23, 2014

By Thomas E. Ban

D-LM at Mobile The qualified success of iron ore pelletizing processes has influenced considerations for production of highly beneficiated fur¬nace charges. Such beneficiation would necessarily involve some forms of chemical and perhaps thermal conversion for production of prereduced pellets, preheated pellets, precalcined pellets, and perhaps pellets which contain all of the above features as preheated, prereduced, precalcined products. This type of furnace burden will be adapted within a new ironmaking process to be activated commer¬cially during the latter part of 196$ in Mobile, Alabama. This process will integrate a new pelletizing system with an electric smelting furnace and the pellets will be comprised of a composite charge blended from metallurgical proportions of iron ore, coal, and limestone. The plant as designed and constructed by McDowell¬-Wellman Engineering Company will feature the D-LM process and will be owned by McWane Cast Iron Pipe Company. It is significant to

Jan 1, 1968

By Yuting Xue, Taghi Sherizadeh, Mark Van Dyke, Dogukan Guner, Khaled Mohamed

The Coal Pillar Rib Rating (CPRR) technique has been developed to assist in rib support design in underground coal mines. One major challenge of the data collection process is the measurement of coal strengths in the field. Schmidt hammer has been verified as a useful tool to determine coal strength. An alternative approach is to obtain the representative strength of coal mass by determining the coal lithotypes in the field based on the coal brightness profile by experienced geologists or mining engineers. In this paper, image processing techniques have been used to quantify the texture of coal images of different lithotypes with the purpose of classifying coal lithotypes. The coal images were collected from the pillar ribs with exposed surfaces in underground coal mines, and the coal lithotypes were identified when taking the images. The method of Gray-Level Co-Occurrence Matrix (GLCM) was used to analyze the textures of coal images of different lithotypes, and the texture parameters, such as contrast, homogeneity, energy, and entropy, were compared. The results show that the images of coal with different lithotypes have different textures, which can be quantified through the image processing. The results from this study demonstrate the potential of classifying coal lithotypes using rib photos and easing the data collection process of CPRR.

Feb 1, 2024

By G. Ofori-Sarpong, A. -S. Adam, R. K. Amankwah

"In the application of the BIOX® technology, high tailings grade (2-16 g/t) may be generated with a decrease in overall gold recovery, which sometimes make it economically unattractive. This paper investigated the causes of the high tailings grade by using samples from the Bogoso BIOX plant. Partial chemical analysis, diagnostic tests and cyanidation optimisation studies were conducted to invoke understanding into the high tailings grades. Diagnostic study on the tailings showed 48.34% of gold in carbonaceous matter, 17.12% in quartz, 13.40% as liberated gold, 11.51% imbedded in sulphides and the remaining 9.65% in carbonates. Optimum cyanidation recovery of 90.4% was established for the BIOX concentrate at 7 kg/t NaCN, 40-50 g/L activated carbon and residence time of 40 hours. The recovery was sensitive to carbon and cyanide concentrations but additional cyanide was not economical. High preg-robbing indices of 72.7% and 64.4% were recorded for the BIOX product and the flotation concentrate respectively. This confirms the inability of the BIOX process to deactivate carbonaceous matter, which remains a serious precursor for low overall gold recoveries and high CIL tailings. INTRODUCTION Gold ores may be broadly classified as refractory and non-refractory. Non-refractory ores are easy to treat but refractory materials require complicated flowsheets for metal extraction (Hausen and Bucknam, 1985; Schmitz et al, 2001; Marsden and House, 2006). As near surface non-refractory gold deposits are getting depleted, the increasing price of gold and increasing demand for gold, have encouraged many gold producing companies to treat refractory ores for gold recovery. The refractory behaviour of these ores may be due to the presence of sulphides, tellurides, cyanicides and/or carbonaceous matter. Refractory ores do not respond well to conventional cyanidation as the gold is either occluded by or in solid solution in sulphides, or is in association with cyanicides (Marsden and House, 2006). Further, carbonaceous matter preg-robs gold during leaching (Osseo-Asare et al, 1984; Hausen and Bucknam, 1985; Schmitz et al, 2001). The two major causes of refractoriness are the presence of sulphides and carbonaceous matter, and these render the ore double refractory (Nyavor and Egiebor, 1992). Oxidative pre-treatment processes such as high pressure leaching/oxidation; biological oxidation, ultra-fine grinding and roasting are required to render refractory ores amenable to conventional cyanidation (Marsden and House, 2006). Biological oxidation, however, has become the preferred pre-treatment route because it is more environmentally friendly and convenient even where only partial oxidation is required. Comparative tests have demonstrated that bioleaching can achieve the same or better results than roasting or pressure leaching in terms of gold recovery (Yannopoulos, 1991; Brierley, 1997). Further, biological treatment processes are more cost-effective, environmentally friendly and safer."

Jan 1, 2017

By Ihsan Berk Tulu, Haochen Zhao, Deniz Tuncay

The process of designing pillars and selecting support measures in underground coal mines relies highly on the accurate assessment of mining-induced loads and the load-bearing capacities of the supports. This study proposes a new method to estimate the percentage of load carried by the gob in underground coal mines using a new parameter that introduces the site-specific overburden geology.

Jun 1, 2023

By Eugene F. Eisemann

This paper is concerned principally with the competition between fuels for industrial use in the United States. Total energy consumption in the U. S. is allocated between industrial and other uses The industrial volume is divided into two classifications (1) where-there is competition between fuels and (2) where there is no competition. The pattern of fuel consumption by electric utilities was studied because there, is competition between fuels and because it is the fastest-growing industrial market. Electric utilities fuel consumption is discussed by geographic area. The growth of each fuel in several areas is investigated. The analysis of these areas, includes the study of the relationship between prices where fuels are in, competition:- (1) on the East Coast where price competition occurs between oil and coal, and (2) in the southeastern states where competition exists between coal and gas..

Jan 1, 1961

By F. A. Campbell

This paper reports on mineral facies, ore textures, distribution of iron in sphalerites, and fractionation of sulfur isotopes in the Anvil ore body, Yukon Territory, Canada. Because the detailed structure and stratigraphy, both regional and local, are being studied by the geological staff at the mine and members of the Geological Survey of Canada, these topics will be discussed only briefly. The results of our study of the Anvil ore body have implications on theories of the genesis of ore deposits of this type, and these will be discussed. The Anvil ore body is the largest and most significant of three lead-zinc discoveries in an area of the central Yukon where major lead-zinc deposits were unknown only twenty years ago. The Vangorda deposit consisting of 22 million tons was discovered in 1953, followed in 1954 by the Swim Lakes deposit consisting of 10 million tons. The Anvil deposit, which consists of three ore zones, was discovered in 1964. The total reserve at Anvil mine is 63.5 million tons, with an average grade of 3.4% lead, 5.7% zinc, 0.16% copper and 1.2 ounces of silver per ton. This study is concerned primarily with the number one ore body which is about 2,400 feet long, up to 1,100 feet wide and 300 feet thick.

Jan 1, 1973

By Donald T. Mylar

It is axiomatic that in designing a bulk material handling system the primary consideration is the functioning of the machines. The structure is secondary -its reasons for being are to support, enclose and provide access to the machine, for servicing. This results in a wide variety of supporting structures. Other considerations are: plant layout, local soil conditions, climate, local laws and codes, and last, but by no means least, the Customer's wishes.

Jan 1, 1971

By Erwin Riyanto, Roy William, Karl Llewellyn

The Deep Mill Level Zone (DMLZ) mine is currently one of the deepest block cave mines in the world. The rock mass is heavily veined with little to no joints and faults are usually healed cohesive structures leading to difficult cave mining conditions. The caving process is improved if the rock mass contains fractures with sufficient density that it will cave by gravity as undercutting progresses. Hydraulic fracturing (HF) has been used to create fractures around the cave to improve mining. A seismic monitoring system has been used in DMLZ since the start of mining. Therefore, the seismic activities before, during and after HF can be monitored. Shear wave splitting is a process used to study the impacts of HF on the rock mass. This process involves the measurement of travel times from splitting shear waves after seismic events and using this to define the anisotropy within the rock mass and subsequently fracture density. This paper sets out the methodology for carrying out the interpretation of the shear wave splitting process using seismic data from the fracked cave crown and abutments along with an overview of the benefits to cave mining as result.

Apr 26, 2022

By Gary Peach, Peter Mason

Planning and estimating progress rates and costs for tunnelling is always best done based on experience and historic precedent. Much precedent is available but the use of data monitoring, data mining and other retrieval techniques on modern TBM machines can enable this to be further expanded and refined. Advance rates can be related much more closely to rock types as can associated rock bolt and mesh/ shotcrete requirements. This in turn can lead to a further refinement in best likely combinations of equipment, such as shotcrete jumbos, better selected for the anticipated conditions, rather than the potential advance rates of the machine. Efficient and timely construction of the tunnel will also be linked to times needed for finishing work, such as contact and void grouting and to how this can be initiated while the TBM is still in operation, in order to save overall construction time. Indeed, this in turn may affect the most preferable layout and construction details of the permanent tunnel. Considerable experience has been gained in the use of two large diameter TBM tunnel drives through the Himalayas at the Neelum-Jhelum hydropower project in Pakistan. All the above aspects will be discussed in the paper based on the considerable experience and data which came from that operation, including appropriate measures in highly stressed areas potentially subject to rock burst.

Jun 13, 2021

By A. House

Newmont Mining Corporation owns and operates the Phoenix Mine near Battle Mountain, Nevada, USA. The existing milling facility has operated since 2006. Following the startup of the milling operation, and coupled with the upswing in the copper market, Newmont realized that Phoenix needed a process option to treat lowgrade transition and oxide copper ores. This meant that potentially revenue generating ore was being mined as waste. With no system in place to treat the transition and oxide copper, work began to determine the most feasible approach. After evaluating multiple options, the flow sheet was set for a run-of-mine (ROM) heap leach pad and solvent extraction/electrowinning plant (L-SX/EW). This paper will discuss the synergies and challenges of developing a copper L-SX/EW plant at the Phoenix copper-gold mill.

Jan 1, 2010

By X. Zhu, Chen. L., R. Guru, M. Peiravi, M. Mohanty, L. Ackah, B. Xu

"The overall goal of this study is to develop a suitable flow sheet to extract rare earth elements (REEs) from coal ash. A total of 14 coal samples of different ranks were examined for REE concentration, and an anthracite coal sample with the highest REE concentration of more than 700 ppm in the coal ash was selected for REE extraction tests. This paper reports on the results of the experimental program completed in the first part of the study, which included hightemperature leaching with nitric acid followed by solvent extraction tests using various organic extractants, namely, tributyl phosphate, Cyanex 572, di-(2-ethylhexyl)phosphoric acid (D2EHPA) and their combinations. A 4×2×2 experimental design was used to conduct a total of 32 high-temperature leaching tests by varying acid molarity at four levels, solids content at two levels and leaching time at two levels. The highest recovery rates of 90 percent for light rare earth elements (LREEs) and 94 percent for heavy rare earth elements (HREEs) were obtained from the optimum leaching test conditions while maintaining impurity recovery to the leachate at less than 40 percent. D2EHPA was found to be the best extractant in this solvent extraction test series, providing an REE recovery rate of nearly 99 percent.IntroductionGlobal demand for rare earth elements (REEs) and other strategic metals is increasing rapidly due to their use in a variety of advanced technological applications, with more than 100 kt of rare earth oxides used worldwide on an annual basis. The United States has less than 10 percent of the world reserves of REE mineral deposits, and in 2013 imported more than 60 percent of its rare earth oxides from other countries, mainly China (United States Geological Survey, 2017). China’s institution of export quotas has significantly reduced supply to the United States, raising the urgency of finding new ways of producing REEs and/ or substitutes. Coal combustion byproducts, which are usually discarded as waste materials, are known to contain REEs in low concentrations that could be extracted with a suitable process flow sheet. This may be a worthwhile route to pursue, considering the short supply of rare earth minerals and the abundance of coal ash in thousands of ash ponds in the United States. More than 110 Mt of coal combustion byproducts are produced annually in the process of satisfying the country’s need for electricity (American Coal Ash Association, 2016), and less than 50 percent of these byproducts are being successfully used in various applications, with the remainder dumped as waste materials in landfills and ash ponds."

Jan 1, 2017

By S. K. Kawatra

A high calcium fluid-bed combustor ash has been shown to be an effective binder at dosages of 1 to 2% of the magnetite concentrate weight. Magnetite pellets 1.3 cm (1/2 inch) in diameter were produced with dry crushing strengths greater than 22.3 Newtons/pellet (5.0 pounds force/pellet), which is comparable to the results produced using conventional bentonite binder. The effectiveness of fly-ash-based binders was considerably improved when calcium chloride was added as an accelerator. Addition of calcium chloride at a rate of 0.1 to 0.2% of the total powder weight increased the strength of dried pellets by as much as 22% compared to the strength of pellets made using fly-ash without accelerators.

Jan 1, 1997

By D. W. Alexander

In 1993, CONSOL began investigating new methods of permanently filling coal mine shafts, which after ventilation is stopped, may contain a potentially hazardous atmosphere. Fill materials such as fly ash/cement can be pumped, are non-combustible and non-incendiary but tend to flow into the mine entries. A non-flowable mixture has been developed that minimizes the volume of fill used. The paper presents our recent shaft filling experience including fly ash material properties, mix designs, field problems, placement success, and gas testing techniques.

Jan 1, 1996

By Murat Budakoglu

Albite (NaA1Si308) is one of the important raw materials for the rapidly developing Turkish ceramic and glass industry. Prior to 1980, development of the ceramic industry in terms of raw material was dependent upon small-scale mining operations; in the last decade, these efforts have increased substantially. The aim of this study is to investigate the geochemical properties and distribution of albite occurrences in the Kocayayla district, which is about 12 km northeast of the town of Milas, about 50 km west of the city of Mugla in southwestern Anatolia. Kocayayla is also well known for its famous ancient city, Labranda. The field area is located in the Menderes Massif, which was formed by major tectonic events during the Late Proterozoic and subsequent periods. The target area was studied to prepare a detailed geological map (scale, 1:10,000), and to determine the formation of albite-mica-schist-quartzite borders in the host rock gneiss. To do this, systematic sampling of albite was done in the two main areas, the Sarikaya and Yumruta? regions. In the study area, albite zones are scattered within an area of about 20 km2, and they extend in a northeast-southwest direction; mica-schists and quartzite veins accompany these units. Mineralogical observations show that quartz is the main mineral associated with albite. In the ceramic industry, the albite + quartz assemblage is well known and is classified as "standard" or "super type," depending upon the content of TiO2 and Fe203. In this study, the Sarikaya albites (profile I) exhibit remarkably lower TiO2 (0.15% on the average) values contrasted to that of Yumruta? (profile 11; 0.24% on the average), whereas Fe203 values vary slightly from 0.076% to 0.085% in both regions.

Jan 1, 1999

By J. F. Barry

Newmont Mining Corporation and Barrick Goldstrike Mines, Inc. concluded an exchange of land and reserves in an agreement signed May 3, 1999.This exchange of assets allowed Newmont to develop the Deep Post underground mine from within Barrick’s Betze-Post open pit, thus reducing capital expenditures, lowering operating costs, and advancing the production schedule by nearly three years. Based on previous experience, Newmont is confident that the Deep Post underground mine can be successfully developed and operated within a large, active, open pit mine. The project also faces difficult geotechnical conditions including weak ground, scattered pockets of groundwater, and elevated rock temperatures.

Jan 1, 2000

By H. E. Cross

In a minerals-recovery context, the object of exercising control over milling operations must be threefold, 1) To achieve maximum recovery at 2) minimum operating costs and 3) making maximum use of installed equipment, Milling is one of a sequence of operations which have as their objective the economic recovery of minerals from mined ores, All operations in the sequence are interdependent and each is both influenced by and itself affects all other unit processes. The part which grinding plays in achieving each of the above objectives is indicated in the following analysis: In South Africa, the most important mining operations are still the gold mines, A vast reservoir of knowledge and experience in treating the Witwatersrand and associated ores has been accumulated. and recoveries are consistently high, However residue values do vary and frequently this is due to fluctuations in the degree of grind, The significance of changes in residue values is indicated by the following example: On a modern mine, the residue values varied from 0,25 to 0,33 dwi; per 2000 lb, during a period of 6 months, The cash value of the gold thus lost varied therefore between $0.44 and $0.58 per 2000 lb, ton. A residue which assays 0.30 dwt per ton would contain approximately 0.26 dwt as undissolved gold and 0,040 dwt per ton as dissolved gold present in residual solution after filtration. This dissolved gold loss is a function of efficiency of filtration and varies from 0.030 to 0,.070 dwt per ton of residue.

Jan 1, 1970

By C. R. Pelley

This paper is intended to describe the utilization of Western subbituminous coal as used in a utility-sized steam generator. It compares this coal's characteristics with those of a typical Midwestern and Eastern coal as a base and reviews the various design considerations when blends of these coals are used. The effects of blending various low-sulfur Western coals with Midwestern or Eastern coals to achieve a predetermined sulfur dioxide emission and the resulting alteration in the coal characteristics as they apply to utilization are also reviewed. The blending of coals as one means of complying with sulfur dioxide regulations will take on increasing importance as the various deadlines for compliance with new and existing regulations approach. We must first consider the availability of these low-sulfur coals; and insofar as the Eastern low-sulfur coals have been mined for many years, we have focused our attention on the availability of the coal reserves west of the Mississippi River in the United States, as this is the area to which many people are turning in order to meet this requirement.

Jan 1, 1976