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By Christophe Bragard, Marte Gutierrez, Haotian Zheng, Michael Mooney

This paper proposes a framework for applying surrogate-based approaches to evaluate SEM construction, which can both benefit the uncertainty analysis in the design stage and real-time calibration during the construction process. The performances of four surrogate modeling approaches, namely back-propagation neural network (BPNN), support vector regression (SVR), random forest (RF), and polynomial chaos expansions combined with Kriging (PCK), were evaluated and compared. A variance-based global sensitivity analysis (GSA) was performed on the surrogate predictor to quantify the impacts of geotechnical parameters on the deformation responses induced by SEM tunneling. The Regional Connector Crossover Cavern project constructed in Downtown Los Angeles was set as the benchmark problem to demonstrate the efficiency and reliability of the proposed procedure.

Jun 13, 2021

By S. Govender, J. J. L. du Plessis, R. C. W. Webber-Youngman

Spontaneous combustion (SC) is a cold oxidation reaction that generates heat, causing a temperature rise of the reactant and leading, with limited heat dissipation, to self-ignition of the reactant, which occurs without an external heat source. Although not limited to coal, the most significant hazard of SC are the fires that occur in coal mining operations around the world. These fires pose a serious risk to the safety of workers in the mines as well as adverse effects on the environment, and can affect the quality of life for current and future generations. We investigated the occurrence of SC in raw coal storage bunkers with the purpose of compiling a decision analyser for engineers designing or working with coal storage bunkers. Specific experts were interviewed from different backgrounds and companies, followed by field research at a coal mine. The important factors affecting the possibility of SC occurring were the type of coal supplied to the bunker, the mining practice, and physical conditions around the bunker. The information presented here will assist in reducing the SC risk in raw coal storage bunkers. These findings, together with the systematic decision analyser developed, will assist design engineers and mine personnel to take early preventative steps in managing SC. The decision analyser was tested for many different scenarios and gave good guidance on how to minimize and prevent SC in bunkers

May 1, 2021

Implementation of an Energy Efficient Dry Grinding Technology into an Anglo-American Zinc Beneficiation Process

Sep 13, 2010

By C. W. Davis, L. R. Messer

THE name fuller's earth, which was derived from its early use in "fulling" or removing grease from woolen goods, is a term that is generally considered to designate mineral matter, containing hydrous aluminum silicates of the clay group, which has a high capacity for removing colors from oils, whether of animal, vegetable, or mineral origin. Fuller's earths are usually dried and may be "tempered" by heating or may be treated with water or reagents to improve their efficiency. For our purpose the term "acid-treated earths" will include those products from the partial decomposition of mineral water by acid which are equal to or more efficient than an untreated fuller's earth from Quincy, Fla., when used in bleaching mineral oil by the "contact" process. In general, the contact process for treating oils consists of heating and agitating a mixture of oil and finely divided adsorbent, the latter being subsequently removed by filtration. The term "adsorbent" is used because, although there has been a great deal of controversy over the mechanism of removal of impurities from oils by mineral matter, there is no doubt that adsorption, which involves the surface of the solid, plays a major part.' The properties that make fuller's earth useful in the treatment of petroleum products by "percolation1' and in the purification of edible oils by the contact process have long been studied, but the comparatively recent adaptation of the contact process to the bleaching of petroleum products has made desirable the further investigation of fuller's earth and other adsorbent earths.

Jan 1, 1929

By Zihe Ren, Edouard Asselin, Marcus Tomlinson, Tianbi Zhang, Jing Liu

"Raman spectroscopy is used to quantify the extent of disorder in the carbonaceous matter associated with preg-robbing ores. Previous studies of Goldstrike ores showed that the height and width of the peaks for the “D” (disordered) and “G” (graphite) bands, the so-called “Raman ratio” had a strong correlation to the preg-robbing value (PRV) measured for various ore samples. A brief literature review on Raman spectroscopy as it applies to preg-robbing ores is presented. Further, recent studies, presented here, have shown no correlation between the Raman ratio and the PRV for a wide variety of ores. This suggests that the extent of organic carbon crystal disorder is not the main factor in determining preg-robbing characteristics.INTRODUCTION Valuable base metals, such as nickel, cobalt, molybdenum, vanadium and tungsten, are used in a wide range of important technological applications. The demand for many of these metals has increased significantly over the last few decades, driven especially by economic expansion in Asia generally and China in particular. This has led in turn to a large growth in the output of mines in order to satisfy this increasing demand, as shown by the data in Table 1 (USGS, 1994, 2014). These data reflect an even longer trend of growth of these metals, with nickel, for example, showing an average rate of 5.3% per year from 1980 until 2015 (International Nickel Study Group, 2017). This rapid and sustained rate of growth means that annual mine outputs for nickel, tungsten, molybdenum and vanadium have had to double roughly every 11 to 14 years, whilst cobalt mine output has had to double roughly every 7 years, over the period from 1994 until 2014. With the average working life of a nickel mine being between 17 and 22 years (Statista, 2017), this means that from the time a nickel mine opens until it closes, the industry needs to find the equivalent of another three or four mines of a similar output to satisfy this relentless growth in demand for the metal."

Jan 1, 2017

By S. Sarac

In this study, graphical and mathematical methods used to determine operating points in single or multiple fan ventilation systems are summarized. The problem is mathematically formulized for parallel connected fans in which analytical solutions are not possible. For n number of parallel connected fans, a non-linear equation system that consists of n number of non-linear equation sis derived. The Newton-Raphson method, which is a numerical analysis method, is adapted to solve this non-linear equation system and the solution steps are given as an algorithm. A computer program based on this algorithm is written and its applicability is proved.

Jan 1, 2000

By F. Alsobrook

Industrial minerals are receiving increased attention by metals, coal and other companies seeking to diversify and stabilize earnings. Each industrial mineral has a unique set (and sub-sets) of business dynamics, however, and the diversity can present a bewildering maze to the corporate planner. Shrugging off this complexity and relying on serendipity for entry opportunities often results in unsuitable acquisitions. An effective alternative used in exploration can also be applied to strategic planning. By providing focus and direction, this flexible methodology can prevent wasting corporate resources on random pursuits and result in a quicker, more satisfactory achievement of diversification goals.

Jan 1, 1990

By Charles E. Glass

The purpose of this report is to demonstrate the flexibility of rte sensing techniques for providing data with which to implement mined-lands reclamation in an efficient and cost-effective manner. An operational program is presented for using satellite remote sensing data, collateral data, and automated image analysis to provide: 1) an inventory of coal and copper mines and mine waste in Arizona, 2) techniques for periodic monitoring of mining areas using multitemporal classification and image prediction techniques, and 3) delineation of high priority areas for future reclamation and current land-use planning of Arizona mining areas based on environmental hazards indices computed using classified scenes and collateral data.

Jan 1, 1980

By Angel Rafael Fernandez, Yahya Khader Al-Harbi, Benjamin Cebrian Romo, Antonio Morato Medina

The kingdom of Saudi Arabia has set the goal to diversify their economy from oil into different fields including mining. As the vast Arabian Peninsula is explored, orebodies of Aluminium, Copper, Gold and Phosphates are found in high grades and tonnages. Hard rock is present in most of the projects and require high quality blasting in regard to ore dilution, wall control and fragmentation. Maaden Gold has currently 4 open pit mining operations 1 new opening and 2 underground. More projects are coming online in the next few months and years. A new generation of mining engineers need to apply drilling and blasting techniques that compete with modern and efficient open pit and underground mines.

Feb 6, 2023

By Lloyd Williams

1. This investigation shows that the Sewanee bed is the only coal bed being mined in Sequatchie County. Other coal beds are present, but as they do not contain known recoverable reserves, estimates of reserves were made only for the Sewanee bed. 2. Known measured and indicated reserves in the Sewanee bed, based on a minimum thickness of 14 inches and on 1,800 short tons per acre-foot of coal in place, are estimated to be 76 million short tons as of January 1, 1953. Of this total 62 million short tons represent coal 28 inches and more thick. Areas in the bed were omitted from the estimate because available data relative to the bed characteristics were insufficient to permit making an estimate conforming with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total estimated reserves determined by this investigation.

Jan 1, 1955

By David J. Hoadley

This report describes the development and underground operation of a semi-automatic, raise climber, Man and Supply Hoist System designed for stope access in underground metal and nonmetal mines. Demonstrated capabilities of the system include a 4000-lb payload capacity, control from the traveling cage and from up to five remote stations, operating in vertical or inclined raises 5 ft in diameter and up to 300 ft in length and a travel speed of 50 ft/min. The 'system has the capability of operating in crooked raises because the conveyance climbs two stationary wire ropes suspended down the raise. The drive unit is electrically powered with power and control signals supplied to the drive unit through an armored cable also suspended down the raise. The system has been designed for portability, ease of installation and minimum raise development. The system can be installed by two men in five shifts. The hoist has been demonstrated successfully in two underground applications. The first demonstration was in a 5-ft diam, 60 deg inclined raise over a 2-month period. The second demonstration utilized a vertical 5-ft diam borehole to access a blast-hole stoping area. The system successfully provided two shift-a-day service over a 7-month duration demonstration. This report provides a detailed description of the hoist design and its demonstrated performance in two mine applications.

Jan 1, 1981

By Nick Hasenack

In the pelletizing plant of Hoogovens, Estel BV, a varying mixture of hematites and magnetites is used for the production of acid and (occasionally) fluxed pellets. Optimum results regarding productivity, quality and process control are obtained with mixtures containing 30-40 % magnetites. A decrease of the magnetite ratio or an increase of the basicity has a great influence on both productivity and heat and power consumption. Tests have been carried out to find the extent to which magnetite can be replaced by b.f. dust, mill-scale and coke breeze. Pilot plant tests show that about 80-100 % of the production loss due to a decrease in magnetite content or to the increase in basicity can be regained without damage to the quality by adding coke breeze. The amount of coke breeze should be limited tot 1,5 %; if this percen¬tage is chosen higher, the quality of the pellets deteriorates rapidly. The amount of coke breeze to be added should be about 30 % above the theoretical value, based on heat balance considerations. The results achieved by incorporating b.f. dust and mill-scale into the pelletmix were also encouraging, but as some types of mill-scale are very difficult to grind and the supply of b.f. dust is limited, the research has not been carried out extensively in this field. The pilot plant tests on replacement of magnetite by coke breeze have been followed by industrial tests, during which the breeze was added to the ore feed before the dry-grinding system.

Jan 1, 1977

By Noel N. Moebs

Bureau of Mines studies of mine roof fall problem in the Pocahontas No. 3 Coalbed of southern West Virgania and southwestern Virginia have established that type and sequence of rock are significant factors in roof competence. The poorest conditions occur where the immediate roof consists of slump structures and slickensided rock. The best conditions occur where the roof consists of a sequence that coarsens upward from shale to massive sandy shale. A small manual of color photographs of rock types was devised to aid in identifying drill cores. Proper identifications should enhance the prediction of areas of potential roof problems in advance of mining.

Jan 1, 1981

By F. P. Morawski, J. E. Schelske, J. R. Geddes, B. R. Eberts, D. M. Wilson, J. D. Jeffries

"The Griffith Mine is located 200 miles northeast of Winnipeg and is 30 miles south of Red Lake, Ontario. Owned by The Steel Company of Canada Limited and managed by Pickands Mather & Co., it has an annual rated capacity of 1.5 million tons of high-grade iron ore pellets with an analysis of 66.3 per cent iron and 4.5 per cent silica.Development of the mine and construction of the plant got underway in January of 1966 and operations began in February of 1968. The orebodies outcrop on the shore of Bruce lake and run under the lake. The ore in its crude form is a metasedimentary low-grade magnetite and occurs in a highly folded banded formation. The average iron analysis of the crude is 29 per cent and the over-all weight recovery is 32 per cent.In order to mine the portion of the orebody under the lake, the soft varved clay on the lake bottom was hydraulically dredged and a dyke constructed of rock, with till used to provide an impervious seal on the lake side of the dyke, prior to dewatering.Mining is carried out by conventional open-pit tech-niques. Ore dressing is achieved by combining one crushing stage and a two-stage grinding system, with beneficiation by magnetic separation, hydroseparation and flotation. Agglomerating is done with conventional balling drums and pelletizing is carried out in shaft furnaces.Of interest and discussed in detail are the 32-foot autogenous cascade mills ."

Jan 1, 1970

By H P. Tardif

This paper briefly describes some of the phenomena encountered when materials are submitted to extremely high pressures, such as those produced by the detonation of an explosive charge placed in contact with the material. It was found that extensive changes take place in the? microstructure of iron and steel. Diffusion-controlled processes, such as the transformation of lamellar pearlite, the recrystallization and grain growth of ferrite, and the homogenization of the pearlite-ferrite structure, can take place within micro-or milliseconds. Mechanical twins can propagate without deviation from ferrite to pearlite, thus indicating a proeutectoid ferrite-pearlite-ferrite orientation relationship. The propagation and interaction of intense stress waves in materials was demonstrated with the use of Armco iron. Finally, a comparison is made of the damage produced in metals by the formation of craters made by explosive shock and by hypervelocity impact. D DRING the last few years, exceptional development has taken place in the field of explosive metallurgy, i.e., the

Jan 1, 1964

By C. M. Harrer

The location, features, qualities, and extent of iron occurrences and the associated resources--limestone and dolomite, bentonite, coal-lignite, petroleum and natural gas, power, and water--are evaluated. The results of pioneer beneficiation tests on South Dakota taconite are discussed. In addition, pertinent features of taconite development, cost factors, the Western and Central United States trade area and markets are reported. The State's production of iron ores until 1963 has been small and for purposes other than the manufacture of iron. This investigation disclosed the probability of large resources of taconite in Pennington and Lawrence Counties. The average iron content is 29 percent, and a 65-percent or better iron concentrate might be produced. Ample resources are available for mining and processing taconite. An investment of at least $26 million would be required for a plant capable of turning out 1 million tons of agglomerated iron concentrate per year. The feasibility of such an enterprise is indicated, but intensive investigation and research must be completed to justify such an investment.

Jan 1, 1966

By J. M. Kuchta

Concentrated hydrogen peroxide (H202) is a highly reactive oxidizing agent that liberates heat when it decomposes. The heat liberated may be sufficient to ignite combustibles with which the peroxide comes in contact. For this reason, concentrated hydrogen peroxide should be handled only by personnel familiar with its many unique properties.6 Hydrogen peroxide is used as a bleaching agent in the manufacture of textiles; this is its major single use in the United States. It is also employed as a reagent in chemical synthesis, as a source of free radicals to start polymerization, as a foaming agent in the manufacture of porous substances, and for its effect on biological processes. Moreover, highly concentrated hydrogen peroxide is a compact source of energy that can be utilized both as a monopropellant and as the oxidizer in a bipropellant system, During World War II, large quantities of highly concentrated hydro- gen peroxide were used as propellants, particularly in Germany. Since then, production of the peroxide has increased rapidly; in the United States alone it has more than doubled since 1950.7 Because of its widespread use, increasing interest has been shown in the hazards of handling the high- strength peroxide.

Jan 1, 1961

By Reza Kamali, Mohsen Bashiri, Hadi Fanisalek

"Half of the input energy to aluminum reduction cell will be lost as waste heat which could be studied for possible recovery. Since price of energy is increasing and the main production cost in primary aluminum industry is energy, so waste heat recovery consideration will be interesting. One of the possible choices for recovering is from aluminum exhaust gases that needs minimum modifications for reduction cell and has no influence on cell heat balance which is vital for the operation. By using heat exchangers with in-line and staggered tube arrangements which placed before fume treatment plant (FTP) we will be able to recover enough amount of heat. The main challenging problem which is necessary to overcome will be the heat exchanger material and its design because of corrosive and dusty exhaust gases from potroom. In this paper, a desalination system with six effects of evaporator is proposed for producing distilled water by using recovered heat from hot exhaust gases. The calculated amount of produced distilled water is around 27,000 / in this specific suggested desalination plant. The suggested desalination plant is based on Hormozgan Aluminum Company data (Hormozal) in Bandar Abbas, Iran which is constructed by the Persian Gulf.IntroductionWaste heat losses arise both from equipment inefficiencies and from thermodynamic limitations on processes. The exact quantity of industrial waste heat is poorly quantified, but various studies have estimated that as much as 20 to 50% of industrial energy consumption is ultimately discharged as waste heat [1]. In order to achieve a final decision for establishing the waste heat recovery plant in any type of industry, a strong feasibility study is mandatory. Also, we need to remember that the possible amounts of energy and suggested process plant for recovery have to be investigated before starting any feasibility study. This kind of study which is important to be finished before moving to feasibility step is mainly a theoretical study, and was done for the Hormozgan Aluminum Company (Hormozal). In addition to the exhaust gases from the potroom, the exhaust gases from anode baking plant appear to have a better potential for waste heat recovery compared to potroom exhaust gases. The average temperature of exhaust gases from anode baking kiln is 120°C higher than the exhaust gases temperature in the potroom. This needs further investigation in a different study, because this study is just focusing on potroom exhaust gases."

Jan 1, 2011

By Vladimiros G. Papangelakis

During the past five years, chemical modelling work at the University of Toronto has elucidated the role of soluble magnesium on the autoclave acidity and has demonstrated why feeds rich in magnesium, and other divalent metals, require more than the stoichiometric requirements in acid to produce a leaching performance comparable to that of low magnesium feeds. This understanding has allowed the calculation of acid additions to the pressure acid leach (PAL) on a less empirical basis. Optimizing acid additions to the PAL confers savings in neutralization costs, ensures high productivity and minimises corrosion problems. Hence, our picture of the solution chemistry inside the autoclave during the PAL process has been substantially improved and is reviewed here. Experimental techniques based on solubility and direct acidity measurements that support the theoretical predictions are presented. Concepts of chemical modelling of electrolyte systems at high temperature and software issues are also discussed. Finally, a better understanding of the solution chemistry at temperature has led to better kinetics models because all metal dissolution and precipitation reactions are acid driven and controlled. . Therefore, reactor modelling efforts by our group are also presented and a reactor model with very good performance, as compared to pilot-plant data, is also made here. Finally, in spite of the above success in PAL solution chemistry and reactor modelling, significant challenges lie ahead in theoretical data gaps and instrumentation; these are also discussed in this paper. Keywords: Laterites, process modelling, pressure acid leach, solution chemistry, chemical modelling, reactor simulation

Jan 1, 2004

Nowadays, technology has improved to extract dimensional stone blocks at quarry sites and also to process these at processing plants for making slabs and tiles. In the process of quarrying and processing, performance evaluation of machinery is very important to achieve optimum output at minimum cost with improved technology. Cost analysis of improved technology includes parameters such as manpower, energy consumption, tool consumption, depreciation, maintenance and also others. The chainsaw machine with long boom and rail in marble quarries and multi-diamond wire saw machine for slab making from granite blocks at processing plants have recently been introduced in India. Thus, a study was carried out under a research project on these machines to assess their suitability. In this paper, performance evaluation and cost analysis of chainsaw and multi-diamond wire saw have been carried out with existing machines on the basis of research findings.

Dec 6, 2010