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By Elburt F. Osborn

The phrase "Clean Synthetic Fluid Fuels From Coal," implies that it is possible to obtain adequate and dependable supplies of fuel without sacrificing the quality of our air, water, and land. Because of the long lead times needed to develop technical feasibility, into commercial reality, however, vigorous efforts must be made now in order to do it. The available options for clean fuels include many exotic sources, like solar and geothermal power, fuel cells, and thermionic and thermoelectric systems. To solve the energy crisis, however, we have three basic energy criteria-abundance, reliability, and commercial availability by 1985. Only processes based on converting coal and oil shale to clean, synthetic fluid fuels can meet all three.

Jan 9, 1974

By Fathi Habashi

New technology first introduced by Nippon Steel Corporation at Kitakyushu in Japan in 1976 now used at a number of plants in other countries, known as dry quenching of coke, uses nitrogen in a closed circuit to avoid environmental emissions. In addition, heat is recovered in the form of steam, from the red-hot coke. In steel plants oxygen is used extensively and therefore by-product nitrogen from air liquefaction can be effectively utilized in this way.

Jan 1, 2014

By C. V. Baltzer, E. L. J. Bingham

Compliance with the EPA's emerging Clean Water Act regulations can be challenging. Open pit copper mines in Arizona have found themselves in a tangled web of changing rules, regulations, and guidance documents regarding storm water and process water discharges. Large mining properties must come up to speed on a myriad of issues including the definition of zero discharge, what constitutes a process related spring or seep, and tailings and waste rock Best Management Practices. The example of the Pinto Valley Mine in Arizona is used to illustrate National Pollution Discharge Elimination System regulatory issues.

Jan 1, 2001

By Florence Munter

This paper provides a discussion of the various federal and state laws governing water quality as related to mining operations. The specific laws addressed are the Clean Water Act, and the Arizona Mined Land Reclamation Act. Topics that will be addressed are mine water and process water discharges, storm water discharges, pollution prevention, dredge and fill, spill prevention control and countermeasure plan, and surface water protection. Proposed changes to the laws and regulations will be discussed. Compliance strategies will be suggested to prevent potential noncompliance and enforcement.

Jan 1, 1996

By G. M. L. Robinson

The Clean Water Act, as administered by the Environmental Protection Agency, has mandated industry, government and the public to comply with potentially conflicting and vague water quality statutes, regulations and guidelines. Universal regulatory strategies have been developed which have introduced and have created regulatory, compliance and institutional conflicts. Conflicts have been created because National water quality performance goals and design standards are vague, and, in many cases, cannot be scientifically justified. Because of regulatory technical requirements to define background and environmentally impacted water quality characteristics, the ability to achieve regulatory compliance is difficult. Difficult issues requiring resolutions includes but are not limited to site specific surface and ground water quality classification systems, water quality standards and guidelines, point and non point pollution sources etc. Because of these statutory and regulatory complexities, a confrontational regulatory system has been created as it relates to: - defining performance criteria in relation to design criteria; - resolving water quality statistical compliance conflicts; - defining laboratory precision requirements; - determining background groundwater characteristics; and - locating a representative point of compliance. Because of these complex regulatory issues, the ability to balance goals, needs and economics has not been achieved or in many cases has not been attempted, without legal intervention. A few examples illustrating where water and waste management compliance conflicts have been experienced.

Jan 1, 1992

By E. F. Jr. Young, H. E. Steinman, G. C. Smith

Through a progressive laboratory and pilot-plant program Jones & Laughlin Steel Corp has analyzed and corrected mine drainage pollution problems at all of its coal mines. In conducting this program, the company found no "typical" drainage discharge. Each discharge point at each mine was unique, so that varied approaches were needed to eliminate stream pollution. To illustrate the variety of these approaches, the treatment of drainage from foul, discharge points at three mines in Pennsylvania will be considered here. The flows and critical analyses of the drainage sources and treated effluents arc shown in Table I. Hydrated Lime Works at Thompson Borehole The discharge stream from the Thompson bore- hole at the Vesta No. 5 mine flowed into a small branch creek where it created a "yellowboy" deposit and affected aquatic life. Investigation indicated that hydrated lime would neutralize the acid and precipitate ferric iron without aeration. Treatment of the 150.000-gpd flow, however, created about 4000 gpd of wet sludge for which there was no nearby accumulation site. With State approval, this sludge was deposited through an unused borehole into an abandoned section of the Vesta No. 6 mine several miles away.

Jan 1, 1970

By J Seppelt, B Akerstrom, J Bubnich, D Seaman, T Waters

The Cadia Hill concentrator at Newcrest’s Cadia Operations has undergone several modifications and upgrades to treat an increased throughput rate of harder ore from the Cadia East block cave mine.Subsequent to the commissioning of the expanded circuit, the flotation cleaner block has undergone a systematic optimisation programme tackling all facets of circuit operation. This included debottlenecking circuit constraints and installation of Jameson cell technology to enhance copper and gold recovery while rejecting fluorine and gangue from the concentrate.This paper outlines the improvements over the course of the project and results obtained from the implemented actions.CITATION:Akerstrom, B, Seppelt, J, Waters, T, Bubnich, J and Seaman, D, 2018. Cleaner circuit optimisation at Cadia Operations, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 457–476 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By B. P. Baruah

A good deposit of high sulphur coals of tertiary origin is existent in North eastern region of India. These coals are known to have indifferent characteristics in comparison to other Indian coals. The general Physico-chemical characteristics are low ash and high volatile matter, calorific value and sulphur content. Sulphur in these coals (70-95% of organic) is mostly affixed to the structure of the coal. Owing to the stringent environmental regulations, the utilization of these coals has severe limitations due to high sulphur content. In the present investigation, sulphur incorporation in to these coals has been discussed along with possible organic sulphur functionalities. The various desulphurization techniques carried out for removing sulphur from these coals have been discussed. Two step oxidative desulphurization processes has been found to be most efficient for organic sulphur removal along with mineral matter and potential toxic elements. Keywords: oxidative desulfurization, potential toxic elements, sulfur incorporation

Sep 1, 2012

By Renee Y. Allee

The Chino open pit mine, concentrator, and smelter are located in Grant county in Southwestern New Mexico. Chino Mines Company is a partnership, two- thirds owned and operated by Kennecott Santa Fe Corp., and one third owned by MC Minerals Corp. (Mitsubishi) of Japan. The concentrator, with a design capacity of 37,000 tons of copper-molybdenite ore per day, was commissioned in July, 1982. Further design modifications have resulted in an increase in throughput capacity to 42,000 tpd

Jan 1, 1986

By Euclid P. Worden

In 1977, an article in World Mining1 reported a total of 2726 rotary blasthole drills in service. This figure included only those machines produced by three of the manufacturers building drills of this type. The total, therefore, is much higher. Rotary drilling in the mining industry is big business to the manufacturers and suppliers involved, and a significant cost item to mine operators. The time has come to take a hard look at rotary drilling technology with an eye to reducing costs by increasing drilling efficiency. The efficiency of any rotary drilling operation is best measured in terms of the rate of penetration achieved by the bit. In blast hole drilling, there are five factors which affect the rate of penetration. They are: (1) bit selection, (2) weight on the bit, (3) rotary speed, (4) hole cleaning, and (5) formation properties. Of these factors, all but one may be controlled by the operator. Looking at any one in detail may reveal possible improvements in the system. One of these factors -- proper hole cleaning - will be discussed in this paper. In order for a bit to perform at its maximum capability, each tooth or insert should strike fresh clean rock as it falls into its drilling position. If the tooth or insert lands on previously drilled cuttings, a major portion of the energy delivered to the bit is absorbed in redrilling this broken material. A major portion of the interest, therefore, should be directed to the proper cleaning of the bottom of the hole. In an in-depth study of the cleaning of large diameter holes, Allen2 reports that horizontal air velocities of 38.10 m/s are necessary to prevent the saltation of drilled cuttings on the bottom of the hole. The exact flow pattern on the bottom of the hole, however, is not generally known. The air leaves the bit through the jet nozzles and the mouths of the cones, but where it goes from there is uncertain. This problem should be investigated by the bit manufacturers because they can best utilize the results of such an investigation to provide a more effective product. Some work has been initiated in this area and competition will probably increase its intensity. Bailing velocity is the best criteria to measure the cleaning of the hole, including the bottom, and is the factor on which efforts toward improvement must be concentrated. The first consideration is "What should the bailing velocity really be?" In drilling deep holes for oil and gas, 15.24 m/s is the generally accepted figure. In blasthole drilling, the figures of 25.40 m/s for average rock to 35.56 m/s for iron ore were first mentioned by Capp3 in 1962. The recommendations are the same to this day. A number of questions could be asked in regard to the apparent disparity between these two sets of figures. Various investigators have derived formulas which support one or another of these criteria. A thesis on the subject was written by Alexander4 who derived a formula based on research which resulted in velocities in the lower end of the ranges quoted previously. He set out to compare this figure to laboratory tests and his tests indicated that the velocities given by the derived formula appeared to be high.1 Perhaps the best reason that the 25.40 to 35.56 m/s range has been used, is that these velocities seem to work. Below the accepted figures, low bit life and slow penetration rates occur. Above these figures, increasing amounts of abrasive wear on the drill pipe and stabilizers seem to appear. There is a fallacy to this entire approach, however. The entire velocity calculation is made using nominal bit and pipe sizes and compressor deliveries with no compensation made for losses in the system. Perhaps an examination of some of the things that are not presently considered could lead to some practical improvements in the operation.

Jan 1, 1980

By Euclid P. Worden

In 1977, an article in World Mining (1) reported a total of 2726 rotary blast hole drills in service. This figure included only those machines produced by three of the manufacturers building drills of this type. The total, therefore, is much higher: Rotary drilling in the mining industry is big business to the manufacturers and suppliers involved, and a significant cost item, to mine operators. The time has come to take a hard look at rotary drilling technology with an eye to re¬ducing costs by increasing drilling efficiency. The efficiency of any rotary drilling operation is measured in terms of the rate of penetration achieved by the bit. In blast hole drilling, five factors affect the rate of penetration. They are: 1. Bit selection 2. Weight on the bit 3. Rotary speed 4. Hole cleaning 5. Formation properties Of these factors, all but one may be control¬led by the operator. Looking at any one in detail may reveal possible improvements in the system. Cleaning the hole is a good place to start. In order for a bit to perform at its maximum capability, each tooth or insert should strike fresh, clean rock as it falls into its drilling position. If the tooth or insert lands on previously drilled cuttings, a major portion of the energy delivered to the bit is absorbed in re drilling this broken material. A major portion of the interest, therefore, should be directed to the proper cleaning of the bottom of the hole.

Jan 1, 1979

By S Sandover, D Glenister

Alcoa World Alumina Australia is committed to sustainability principles as a basis of business success into the future. In March 2001, Alcoa Inc chairman Alain Belda announced a set of far-reaching environmental goals for the corporation, with the challenge that they should be achieved in ways that enhance economic and social performance, while substantially reducing environmental impact. Application of Cleaner Production methods is seen as the key to achieving these joint objectives. In Australia Alcoa has launched a co-ordinated effort to accelerate our application of Cleaner Production principles to delivering cost-effective in-process solutions to environmental issues. Our Western Australian Operations are a signatory to the WA Cleaner Production Statement, through which we provide a Cleaner Production Plan to the State Government on a voluntary basis. This paper describes in general terms AlcoaÆs goals, achievements and directions in applying Cleaner Production to enhance business performance in the economic, environmental and social dimensions. Quantification of the benefits and tracking of progress in quantitative terms is a key challenge for the future

Jan 1, 2002

By A. K. Fallaw, G. Wang, L. R. Moore, S. Dobson, Y. Xiong, J. Gu

"As ores degrade, mining techniques and chemistries change to meet market demand and maintain product quality. The balance of recovery and grade is a significant challenge in the Crago Process where an anionic collector is used to float phosphate, followed by acid scrubbing, then an amine float to improve product grade. As the grade is a requirement for DAP and MAP production, recovery is the criteria to suffer. Phosphate losses in the amine float can bring overall recovery down by as much as 18%, creating a growing need to think outside the box to improve recovery. This paper will focus on the theory of amine tail recycling and the best methods to optimize the overall phosphate recovery by recycling the tails from the cleaner flotation step. INTRODUCTION In 2014 the total US phosphate production was down 13% over the prior year, from 31.9 to 27.1 Mt, which accounts for 12.32% of the world’s phosphate rock production. Florida and North Carolina phosphate production accounted for 80% of total US phosphate production, which was down from 85% the previous year. This decline is due in part to the closing of the last phosphate mine in Polk County, FL - which had an operating phosphate mine for over 100 years (Gurr, 2015). Another factor contributing to the reduction in contribution from FL & NC is the increasing challenges in beneficiating the remaining ore deposits. The Central Florida mining district has historically been in the Bone Valley deposit, where raw apatite was abundant with P2O5 values as high as 15%. The Bone Valley ore also had characteristics favorable to beneficiation to 27.5-29.7 %P2O5 while achieving recoveries above 86%. The move southward into the Hawthorne Formation has seen the ore feed grade hit some historic lows, and the matrix characteristics pose more challenges to phosphate producers. The Hawthorne Formation experienced lateritic weathering after the Bone Valley formation which altered the apatite to aluminum phosphate minerals, and alteration of montmorillonite to kaolinite, releasing MgO that caused the dolomitization of the top of the Hawthorne limestone (Cathcart, 1966). Elevated levels of dolomite can yield an increase in slurry viscosities, reduce production rates, and increase energy costs in the wet-acid fertilizer process. The MgO will also act to dilute grade, making it more difficult to achieve a standard 18-46-0 product (McHardy, 1981)."

Jan 1, 2016

By D. R. Mitchell

This paper discusses some of the fundamental physical and chemical characteristics of coal in Illinois that affect its preparation for the market. At the present time preparation consists almost entirely of sizing and hand-picking. The washing of coal has almost entirely disappeared from the state. This is a rather startling fact when one considers that in the year 1908 Illinois outranked all other states in the quantity of coal washed and a few years later, in 1912, 85 washing plants were reported. Two reasons are apparent for this change. One, which is probably the most important, is that immense areas of comparatively clean coal were opened; the other is that many of the early washing plants were inefficient, so that washed coal was looked upon with disfavor in many trade centers. Objectives of Operators Some of the outstanding preparation aims being given due consideration by operating men are: 1. The greatest possible production of lump and domestic sizes which bring in the market at least $1 per ton more than the fine sizes or screenings. 2. Efficient screen sizing with as little breakage as is consistent with economical operation. 3. The removal of extraneous ash and sulfur. 4. Utilization of low-priced screenings. 5. Suppression of dust in domestic coal shipments. Preparation Underground To get the greatest possible production of the larger sizes, preparation must start at the face. Improvements in blasting and loading have increased the sizes larger than 2 in. by as much as 20 per cent. at some mines. Tiffany and McKitterickl report the results of an investigation they made at a mine in southern Illinois in which, by a carefully controlled

Jan 1, 1931

By Ray W. Arms

The combination wet and dry coal-cleaning process is not an attempt at a compromise between the wets and the drys nor is its merit confined entirely to the limitation of moisture in the smaller sizes. It is more correctly, and more broadly, an application of the sized-coal cleaning principle adapting itself in an ideal fashion to present day multiple-size preparation practice. The purpose of this paper, therefore, is to call attention to the broader significance of the term "combination wet and dry process" and to mention some of the factors that govern its application. In the narrow sense, when considered apart from the sized-coal cleaning principle, the combination process finds its justification chiefly in the ability to limit the moisture in cleaned coal. Larger sizes of coal offer less superficial area compared with their bulk for the attraction of moisture films. They drain more readily in bins or railroad cars, having more interstitial space for the free flow of water. Therefore, they neither attract nor hold objectionable moisture percentages. In fact, there is so keen a demand for certain washed sizes containing some moisture that hygroscopic salts such as calcium chloride are applied to attract and retain it. When coal deliveries are made on a guaranteed moisture percentage the coarser sizes may be washed and mixed back with the fines without adding greatly to the original moisture but the fines must be dry cleaned or dried to control moisture. Thus in all respects moisture in the coarser sizes is less objectionable than in the fines. The implication of this statement, that moisture is always more or less objectionable, is true. It is safe to say that if dry-cleaning apparatus could be perfected to a point at which its technical results, cost and other aspects would be equal to wet washing, water would no longer be used. As it is, we find that good technical results are more difficult to obtain by dry cleaning than by water. Obviously the use of air tables for coarse coal is not ideal, for it involves the attempt to stratify material in a thin bed on a table surface when the load is only one particle deep. Furthermore, the various air cleaning tables on large sizes require a large volume of air for separation, more power to operate, more dust-collecting apparatus and involve more coal breakage.

Jan 1, 1931

By Thomas Fraser, Robert MacLachlan

The dry cleaning of coal is a relatively new art and, as might have been expected, a number of unforeseen problems have been brought to light in the few years that dry methods of treatment have been in commercial use. The pneumatic concentrators that were first adapted to the cleaning of coal had already been developed to a fair degree of efficiency, although at low ratings, in the field of ore dressing. The concentrating machines, therefore, were in a relatively more perfected state than the general technology of dry cleaning and, for this reason, the major difficulties encountered in the early plants were in the accessory operations involved in the servicing of the cleaners rather than in the functioning of the cleaners themselves. The crudities of a new technology were further aggravated, in some cases, by meagerness of appropriations which precluded even the provision of adequate storage bins and such other facilities as had been long recognized as indispensable to the proper functioning of older types of cleaning plants. The practice of dry cleaning is now sufficiently established so that we may examine critically auxiliary equipment and operations. The cleaning processes have been so simplified, with respect to presizing of the raw coal required and the quantity of air circulated, that stinting of expenditures for auxiliary equipment is not necessary to keep the per ton cost of installation in line with complete and well designed plants of other types. Furthermore, sufficient operating experience has been accumulated to ascertain the conditions most conducive to effective operation of dry-cleaning machines; at least the essentials of a definite technology of dry cleaning has been established. Early Operating Problems The problems that have occupied the builders and operators of dry-cleaning plants from the beginning have been relatively few, but difficult of solution. The principal difficulties have been: 1. The proper sizing of the raw coal to suit the cleaning process. 2. The handling of raw coal when it is delivered wet from the mine. 3. Dust collecting. 4. The maintenance of uniformity in cleaning performance.

Jan 1, 1931

By J. F. McLaughlin

The installation of the Chance flotation system for the preparation of anthracite demonstrated the need for some means by which the specific gravity of the fluid mass in the separating cone could be determined with a fair degree of accuracy. The means used (with the original cones) was a set of wooden balls attached to ropes or chains, each with a different specific gravity. In the Northern Anthracite field, where the cones are generally operated with the specific gravity at 1.65, these gravity balls are provided with a range of 1.6, 1.65, 1.7 and 1.75. The operator of the cone from time to time would place one or more of these balls in the cone and estimate its specific gravity by the action of the balls. The margin of error with this system was very great, because there was the possibility that the test ball might be held in suspension and carried around by material floating beneath the surface of the cone in what is known as "island " formation—a formation resulting from a low sand line in the separating cone. The inaccuracy of this system of determination of specific gravity was indicated also by periodic tests of the final refuse bank, which showed excessive losses of coal to the refuse. Further evidence of the unsatisfactory operation of the cone was the uneven appearance of the market product, which caused spasmodic condemnation. Maintenance of Even Preparation With the critical market condition of today, it is essential that the preparation units operate consistently to maintain an even preparation. If a plant wishes to maintain a 1.65 specific gravity preparation, which means that all material of a specific gravity greater than 1.65 is classed as "reject," if the specific gravity of the fluid mass runs to 1.70, the market product will not be satisfactory; or if the specific gravity of the fluid mass is 1.60, the market product will be entirely satisfactory but the losses at the slate ends will be excessive. The desired specific gravity of the fluid mass in the Chance cone is maintained by agitating the sand within the separating cone by means

Jan 1, 1931

By R. G. Baughman

With the constantly increasing sales competition, coal to be sold today must meet the test of quality in every respect. The producers must be able to make all marketable sizes that will meet such general requirements as follows: 1. Ash content must be consistently low, depending upon the use to be made of the coal. 2. Sulfur content must be controlled accurately according to requirements. 3. All sizes must be positively free from visible impurities. 4. Free moisture of washed sizes must be reduced to a minimum. 5. The freezing of wet coal in cars must be prevented. 6. The percentage of fines in small mixed sizes must be controlled to give the uniform and proper combustion when used on various types of automatic stokers. 7. The undersize particles or degradation caused by handling must be kept to an absolute minimum in all sizes loaded. Many difficulties may be met in bringing any particular coal to meet these quality requirements, because the extent to which the quality of a coal may be controlled is determined largely by its physical characteristics. Preparation of an Impure Coal Bed The application of modern and scientific methods in the controlled preparation of bituminous coal from a bed in the mid-western field will illustrate the results that can be accomplished by adequate preparation: The bed referred to contains coal inherently excellent as to low ash and other desirable characteristics; in fact, the coal itself is one of the best in the field. It is, however, divided into four layers by dirt bands of soft shale 1 to 2 in. thick. It also contains much sulfur in the form of sulfur lenses and laminated sheets. Horsebacks or rolls varying from 6 in. to 12 ft. in width are encountered in the mining of the bed and heretofore have rendered it practically unworkable. The mines operating in this

Jan 1, 1931

By H. F. Yancy

PooR results in coal washing and in ore concentration are sometimes attributed to the shape of the particles in the feed. It is well known that the shape of a particle influences its rate of fall in water. This is evidenced by the value of the constant C in the Rittinger equation for the velocity V of settling in water, V = C-D(d- z ), where C has the following values: 2.73 for roundish grains, 2.37 for long grains and 1.92 for flat grains. This report, which is based upon data obtained during the course of coal-washing investigations conducted by the U. S. Bureau of Mines in cooperation with the College of Mines of the University of Washington, gives the results of a method or procedure of screening in which the particles are separated into three shapes and shows the deportment of these shapes when coal is treated on a coal-washing table. The method consisted in first screening the coal with Tyler standard square-hole sieves, followed by screening tests of each of these products with screens of rectangular opening. For this purpose Tyler "Ton-Cap" screens were used; each square-hole product was subsequently sized with two Ton-Cap sieves so selected that their shortest dimensions were approximately 75 and 50 per cent., respectively, of the opening of the square-mesh sieves. For example: A product which is through 8 mesh (0.093 in.) and on 10 mesh (0.065 in.) is screened on slotted sieves which have openings 75 and 50 per cent. of the 0.065-in. opening in one direction and an opening of not less than 0.065 in. in the other direction. For convenience in discussion, the particles retained on the first slotted screen are termed "cubical"; those retained on the second slotted screen are termed "prismatic" and those passing the second screen are called "flat." (See Fig. 1.) The square-mesh screens separate particles according to two dimensions, length and breadth; the slotted screens divide them further according to the third dimension, or thickness. Prismatic particles have a mass of about two-thirds, and flat particles of about one-half, that of cubical particles of the same square-mesh size. The screen-

Jan 1, 1931

By Kenelm C. Appleyard

In introducing to an American audience a description of the work done in dry coal separation in England and in Europe generally, it is perhaps desirable to give a short history of the development outside the United States of the particular processes with which the author is connected, and perhaps to stress a little the differences in the nature of the conditions to be faced. England actually presents one set of problems and the Continent of Europe another, since the character of the coals to be treated is entirely dissimilar, and the attitude of the coal industries towards coal preparation is also dissimilar. England for generations has been working by hand good seams of clean coal of the highest possible quality and has not felt any pressing need to clean its coal. Most Continental countries, however, especially in Central and Western Europe, have been working friable and often very dirty coals for so long that a washery is accepted as a part of the normal equipment of a colliery, with the result that the art of wet washing has reached a high state of perfection, particularly in Belgium and Germany. The advent of machine mining has intensified the problems to be faced in all countries, and in England has been coupled with the working out of the best seams in the older coal fields, thus bringing about the necessity of working thinner and dirtier seams with resultant difficulties as regards marketing the products, while Poland, with clean and well prepared coal, has in recent years been attacking established British markets in Scandinavia. In recent years, therefore, interest in coal preparation has been steadily gaining ground in England, although it has not yet reached Continental dimensions. Broadly speaking, the differences in preparation problems between England and the Continent boil themselves down to one of size. In England, for example, with the exception of the Kent coal field, the proportion of coal of a size less than ? in. to the coal less than 2 in. is very much less than on the Continent, and since the principal difficulties in dry cleaning lie in the fines it is easier to produce good figures on

Jan 1, 1931