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THE furnace described in this paper was installed and has been used by the writer for the melting of rich gold-bearing material, and has given complete satisfaction. It may, therefore, prove of interest to other metallurgists who are faced with a similarproblem. A furnace of this type should be most suitable for the reduction of "cyanide preeipitate," "charcoal ash," "anode sludge," &c. formerly the melting was done in fire-clay crucibles, using coke or crude oil as fuel, but this method is costly, slow, and unsatisfactory. A small water-jacketed blastfurnace was also tried on this material after briquetting it, but was discarded in favour of the electric furnace. The furnace may be described as a simple form of the Heroult resistance furnace, with an adjustable upper electrode and a fixed bottom electrode. This is in accordanee with Stansfield's classification of electric furnaces. The heating is mostly due to the resistance offered the current by the molten slag. The melting chamber consists of a steel drum 14 in. in diameter and 21 in. high, and is lined with silica bricks specially made to fit the shell. The internal diameter is G in. The bricks contain 92 % silica, are made from calcined quartzite bonded with fireclay, and are similar in composition to those used for lining steel converters. They are set in a mixture of finely-ground quartzite and clay, and well dried out. The shell is bolted to a steel plate, which forms the decking of a truck running on rails, so that the furnace can be moved under ahood for carrying off the fumes. A cast-iron slag spout is bolted to the shell below the tapping hole, which is 4 in. from the bottom of the shell. Opposite this another hole 1 in. in diameter is drilled through the shell and lining for the passage of the lower...

Jan 1, 1918

By W. D. Striffler

Land disturbed by surface mining in Colorado and other western states has increased substantially over the past several years and is likely to increase even more in the future. This study was initiated to provide basic information on hydrologic and erosional characteristics of regraded coal spoils in Colorado as an aid for planning future reclamation activities. Eleven of twenty-one surface mines licensed in Colorado were sampled during the summer of 1980 and 1981. Mines not sampled included mines which had not progressed to the point that reclamation had begun, and mines where operators denied permission to sample. All coal regions were sampled with the exception of the San Juan Coal Field. Physical and hydrologic characteristics of regraded coal spoils in Colorado were determined using standard field and laboratory procedures. Field sampling included characterization of sites (slope, vegetation density, proportion of surface rock, bare soil, etc.) and infiltration measurements using a l-meter square drop former raining on a 1/2 square meter rectangular plot frame. Core samples collected in the field were analyzed for saturated hydraulic conductivity, bulk density, organic matter, moisture retention and texture. The erosion potential of each site was determined using the Universal Soil Loss Equation (USLE). Results of the sampling indicate that infiltration rates vary widely both within and between sites. However, definite trends with respect to coal fields are apparent. For example, the Green River (Yampa) coal region had a wide range of sampled infiltration rates (1.2 to 5.1 cm/hr). However, most of the sites clustered towards the low end of the range. The North Park (Marr Strip) also was rated at the low end of the infiltration range (2.0 to 3.0 cm/hr). Average infiltration rates for the Canon City and Uinta Coal Regions were at the high end of the range (4.9 to 5.5 cm/hr). Multiple correlation analysis of infiltration rates vs. site characteristics showed that infiltration rates were most closely correlated with the depth of wetting, the amount of mulch cover, and site slope. The depth of wetting was highly correlated with the depth of the topsoil and the bulk density of the spoil. In general, the topsoil at all sites appeared to be highly permeable to water intake but once saturated, subsequent infiltration depended upon characteristics of the underlying spoil. Vegetation cover affected infiltration on individual mine sites but was not as pronounced as topsoil characteristics or mulch. Erodibility of topsoil and spoils, as determined by Wischmeier's "K" factor, ranged from 1.34 to 0.56 tonnes/ha. (topsoil) and 1.25 to 0.66 tonnes/ha. (spoils). Definite trends in erodibility are evident. The Green River (Yampa) Coal Region displayed consistently higher erodibilities (1.34 to 0.75 tonnes/ha.) than other coal fields (0.72 to 0.56 tonnes/ha). Lowest erodibilities were observed in the Uinta, North Park, and Raton Mesa Coal Regions (0.56 to 0.62 tonnes/ha). Erodibilities of underlying spoils showed similar trends as the topsoils. Erosion potential (the product of soil erodibility and rainfall erosivity) was detennined using calculated ?K? factors and rainfall erosivities (R) taken from Clyde (1976). Results show that the Delagua coal field, Raton Mesa Coal Region had the greatest erosion potential due to the high rainfall energies in the region, while the North Park and Uinta Coal Regions had the lowest potential erosion.

Jan 1, 1981

By B. Tanda

A process has been developed at Curtin University whereby glycine is used in an alkaline environment to leach gold, silver and copper from their ores, concentrates, process intermediates and wastes. Copper mineralisation investigated includes various oxides, sulfides and native copper. The leach process utilises an oxidising environment such as oxygen. Glycine is a non-toxic, non-volatile, edible, low cost reagent which is produced in large industrial quantities for use in several industries. Glycine and its copper and precious metals complexes are stable over wide pH, Eh and temperature ranges. Other than losses in leach residues, the glycine is recovered and recycled for leaching. Iron dissolution is insignificant in the pregnant leach solution. Iron in pyrite remains unaffected, whereas iron associated with base metal sulfides (e.g. chalcopyrite and bornite) is converted to a readily filterable iron hydroxide. Efficient separation of copper by solvent extraction and conventional electrowinning has been shown to be feasible for a number of organic extractants, whereas gold and silver glycinates adsorb very well onto carbon allowing CIP/CIL/CIC (carbon-in-column) based processes. The process is ideal for ores containing acid-consuming gangue, concentrates with high arsenic or halide contents and for copper-gold ores with significant sulfide mineralisation. The process eliminates many of the problems associated with the processing of copper-gold-silver ores, such as elemental sulfur formation, silica gels, unwanted metal co-dissolution, and jarosite precipitation. The reagents used and process residues are much safer and environmentally benign than conventional process options. The processing technology can be applied to in-situ, heap and vat, or agitated tank leaching at temperatures ranging from ambient to below 100?C at atmospheric pressure and is currently being commercialised. This paper will focus on copper leaching and recovery and iron rejection from a chalcopyrite flotation concentrate.

Jan 1, 2016

CrusherMapperTM - A New Tool for Crusher Condition Monitoring The efficiency of mineral processing plants is entirely dependent on the availability of the plant equipment critical path. This typically concerns comminution circuits consisting of primary crushers and primary grinding mills. Crusher and mill availability are determined by the frequency and duration of maintenance shutdowns, which are primarily driven by the need for replacement of sacrificial liners. The change of crusher and mill liner shape over respective life cycles also strongly affects plant efficiency. It is therefore highly desirable to accurately monitor the condition of mills and crushers in order to optimise plant efficiency through maximised availability and targeted liner shape. Traditional comminution liner and other production parameter condition monitoring has been attempted through ineffective methods which prevent satisfactory management of crusher and mill maintenance and reduce operational control. This situation has recently dramatically improved for grinding mills through the development and commercial deployment of MillMapperÖ, a technology based on three-dimensional laser scanning data and dedicated software (Franke, Lichti and Stewart, 2006; Franke and Lichti, 2007; 2008; Franke, 2008; Franke, Redman, Johnson and Michalek, 2009). At the time of writing in late 2009, MillMapperÖ is in successful use at a rate of approximately 170 surveys and associated reports per annum at processing plants in Australasia, South America, North America and Africa. This paper presents the introduction of CrusherMapperÖ, the MillMapperÖ equivalent for crushers. CrusherMapperÖ also utilises high density, high accuracy laser scanning data, and features dedicated algorithms for three-dimensional monitoring of wear on crusher concaves and mantles. This facilitates the detection of wear hot spots or zones or localised liner failures, and accurate forecasting of reline tonnages and dates. It also for the first time provides the means to establish optimised concave and mantle shapes in order to achieve production targets. In contrast to any other currently utilised condition monitoring method, CrusherMapperÖ data collection can occur remotely and does not require any shutdown or crusher isolation. This method therefore does not interrupt crusher production while at the same time eliminating any confined space risk normally associated with taking measurements inside the crusher cavity.

Sep 13, 2010

By G. Budge

In the extractive industry the term ‘continuous improvement’ (CI) usually means procurement of the latest state of the art equipment. This is generally perceived as the only way to add further value to the supply chain, with the driving philosophy of increased tonnage to dilute operational costs. However, not all market places can facilitate this approach. RJB lives in a fiercely competitive market and has targeted the standard efficiency drivers of rationalisation and stock management with a vengeance; and also operate CMMS (Computer Maintenance Management System), RCM (Routine Condition Monitoring)and CBM (Condition Based Maintenance) methodologies. Ultimately though, these systems are only as good as the people who operate and manage them and to add further value without procurement, people must be re-introduced back into the operation. Through TPM (Total Productive Mining), that is what RJB have set out to do.

Jan 1, 2001

By William A. Hustrulid

An overall summary and the individual reports of eight workshops to determine research and development needs in western mining ore presented. Problem areas are identified, and recommendations regarding priorities, funding sources, and prime movers are made. The objective of this contract was to identify research and development needs for advancing mining technology as well as health and safety measures for western U.S. Surface and underground mining. This was accomplished by convening a series of workshops where problems could be thrashed out by producers of trona, uranium, open pit copper, underground salt (from the Midwest and New York), underground metal and nonmetal, etc. In addition to problems, future priorities, funding, and the desicion as to who should be the prime mover on R & D were discussed.

Jan 1, 1976

By Jesús Ylazaca

El presente trabajo describe el método de control de calidad del mineral o el denominado "Ore control", realizado en la unidad minera Yauli, cuya finalidad es maximizar el valor del mineral minado para lograr una mayor rentabilidad. En este sentido, el "ore control" es la gestión que optimiza las diferentes etapas de la exploración, explotación y concentración del mineral para lograr una buena calidad de producto (concentrados), a fin de satisfacer las necesidades del cliente. Los controles involucran a la Gerencia y el total de supervisores y trabajadores de operaciones, quienes deben ser proactivos ejecutando acciones preventivas más que correctivas.

Sep 12, 2005

By R. S. Dean

"It has long been recognized that the properties of polycrystalline substances are not the same as those of single crystals. These differences are especially marked in metels and metallic minerals, and are of greatest practical importance in metal working and ore treatment. The property changes encountered in passing from a metal single crystal to a poly-crystalline aggregate are the same as are produced by cold-working a metal or by the precipitation of a disperse phase. Hence, we may logically assume that the property changes are all due directly or indirectly to the formation of interfacial area or internal surface. Our problem, then, is to ascertain the physicochemical state of the metal atoms at such internal surface and show how this physicochemical condition accounts for the pronounced changes of mechanical, magnetic, and electrical properties that accompany increased internal surface.GENERAL CONCEPT OF INTERNAL SURFACEIn 1678, Huyghens attempted to explain the double refraction of calcite by postulating that crystals were built from a regular arrangement of ellipsoidal particles. Over 100 years later, Abbé Hauy concluded from his studies of cleavage that crystals might be built from small units, but the units were of the same shape as the entire crystal. This idea, which was prevalent in mineralogical thought before the advent of X-ray spectrometry, was discarded when the great success of Bragg made it appear that the chemical atoms were in reality the elements of structure. In the further development of X-ray technique, however, C. G. Darwin, in England, and P. P. Ewald, in Germany, found it necessary to postulate crystal units con¬taining many atoms. The latter gave the name of mosaic crystals to those so constituted. The individual units are supposed to Possess the ideal atomic arrangements revealed by the X-ray but are not oriented with respect to one another."

May 1, 1938

By W. A. Krivsky, R. Schuhmann

Jan 1, 1962

By X. S. Tan

This paper deals with the analysis of stress condition on the interface between two types of floor rock materials when the vertical stress is larger, or when the horizontal stress is larger in a rectangular opening. It indicates that the floor Failure and the failure stress of floor rocks are closely related. It also demonstrates that a larger horizontal stress is one of the most important factors in increasing the potential for floor rock failure and floor heave.

Jan 1, 1990

By M. S. Raseroka

An experimental rig has been constructed to produce chloride stress corrosion cracks in Type 304L stainless steel tube samples. The samples are to be used to test possible in situ repair methods in future work. The factor which influences the time to failure most strongly is the sample temperature; the distribution of cracks within the sample is affected by local temperature variations and by the position of the water line. Low-frequency oscillations in stress, caused by the on-off temperature controller, did not appear to influence cracking in these tests.

Jan 1, 2009

Hatches Creek has been inactive since 1961, but with better metal prices, interest in the field is reviving.The mixed gravity concentrates which were unsalable in 1951 have been experimentally separated into salable wolfram, scheelite, and bismuth-gold concentrates, and a flow sheet incorporating magneticseparation and flotation has been developed.

Jan 1, 1965

The Effect of Mineral Liberation on the Floatabilities of Pyrite, Arsenopyrite and Arsenian Pyrite for Carlin Trend Ores

Sep 13, 2010

By Masami Hayashi

The Bureau of Mines conducted laboratory studies to investigate methods for desilicating sodium aluminate solution derived from leaching a limestone-anorthosite sinter with 10-pct Na2C03 solution. Desilication tests were made at atmospheric pressure to determine the effects of time and additions of lime and desilication residues. A two-stage, countercurrent desilication procedure was developed to reduce the Si02 content sufficiently to meet specifications for cell-grade A1203. Both stages were conducted at boiling temperatures at atmospheric pressure. Reagent lime was charged as desilication seed to the partially desilicated solution in the second stage, and a product (desilication residue) precipitated by the lime addition was charged to the freshly leached solution in the first stage. Average A1203 loss in the desilication circuit was 5.8 pct, and the product solution contained less than 0.04 g/l Si02. Complete precipitation of A1203 by carbonation resulted in a hydrate containing less than 0.01 pct Si02. Calcination of this hydrate would produce A1203 meeting the 0.015 pct Si02 specification for cell-grade material.

Jan 1, 1982

By Mark C. L. Patterson

Hydrothermal brines are extracted from significant depths below the surface of the earth and arrive at the surface at elevated pressure and temperature. The exact chemistry and conditions of these brines depends upon the rock formations through which the water travels, but many of the brines are rich in dissolved minerals especially silica which is often saturated in the brine. At pressure and temperature the minerals remain in solution but in order to extract heat from the brines, they need to be cooled and during which many of the minerals precipitate causing problems. Where precipitation is a problem in the downstream processing, the brines are maintained at a high enough temperature and pressure so as to avoid precipitation and injected back into the geothermal formation. This results in a significant loss in potential energy that could be recovered from the geothermal brines. If left to precipitate in an uncontrolled manner, many of the minerals will precipitate as gels, in a high surface area form which is difficult to extract from the liquor and which can causes problems. Precipitation in this manner often builds up on the inside of pipes, reducing the pipe cross-section available for fluid flow and reducing the overall efficiency of the plant. If the brines are seeded at the appropriate time or the precipitation conditions are changed, mineral particles can be grown and separated more easily from the brine. During this precipitation and growth phase the chemistry of the local environment can also be altered to grow more valuable particulates. Some of the specific chemistries will be discussed with reference to known geothermal brines and what needs to be done to precipitate value added products. A theoretical approach to the complete extraction of minerals from geothermal brines is also discussed with the goal of extracting more heat from the brine prior to reinjection into the well.

Jan 1, 2006

Total mechanisation in the Western district of New South Wales is quite a recent addition to productive methods in that State, for it was only in 1940 that the first colliery was equipped for this method of winning coal. Now almost all mines either are totally mechanised or are planning to get their coal by these means.This marked change in recent years is explained by the salient features of the industry's history. Collieries in New South Wales had generally been subjected to low selling prices forced on them by over-production and severe competition. Little money was available out of profits to purchase machinery, and returns on capital were so poor that inducement to invest money in the industry was nonexistent.The second world war brought price fixing at the already low prices. It was not until the post-war period that there has been any inducement to mechanise.Much credit for mechanisation can be given to the Joint Coal Board, a government body formed in 1948. Pursuing a broad plan for the rejuvenation of the industry, this Board, purchased large quantities of machinery for use in, mines under hire-purchase agreement. These agreements encouraged machine mining, and this fact, together with the ensuing production economies, has improved the financial position of the industry.The Board has also been instrumental in the granting of increases in the fixed price of coal, so that the industry has been given an even greater boost in the direction of mechanisation.

Jan 1, 1954

By R. R. Sayers

A series of coal- mine catastrophes in the latter part of the first decade of this century focused public attention on the need for safety in mines and resulted in the establishment of the Federal Bureau of Mines , whose primary function was to promote safety and improve hygienic conditions of workers in the mineral and related industries . These activities are carried out by the Safety Division of the Bureau's Health and Safety Service . In general , the work performed by the Safety Division personnel may be classified as educational and investigative . Instruction is given in accident prevention for mine officials and miners ; first aid to the injured ; the use and care of oxygen breathing apparatus ; and advanced mine rescue and recovery operations . A specialized safety course is offered to the petroleum and gas industries . Division personnel also aids in or directs rescue and recovery work after mine fires and explosions ; assists at first - aid and mine rescue contests ; conducts safety exhibits and demonstrations ; and presents safety talks , often accompanied by sound safety motion pictures or latern slides , before employee and official groups , at meetings of Holmes safety chapters , at mining institutes , and at other safety or technical gatherings . Coal - mine fires and explosions are investigated , as well as quarry or metalmine explosions and fires , miscellaneous accidents , health and safety hazards , and safety conditions at mines and plants ; safety devices are investigated and developed . Field studies cover ventilation , methods of allaying suspended coal - dust particles , prevention of dust accumulations , the proper use of rock dust to prevent or limit explosions , explosives practices , and the care and use of underground equipment . The results of these studies and investigations are widely applied in the various training courses and are prepared as reports and recommendations , which are submitted to interested persons or are combined and distributed to the public as bulletins , technical papers , miners ' circulars , information circulars , and reports of investigations . These studies also afford a basis for the development of new or modification of old Safety Decisions of the Mine Safety Board of the Bureau of Mines . The following pages review the accomplishments of the division as regards safety during 1942,2/ with like information for a series of recent years and summaries to date . A striking feature of the division's work has been the safety education of more than 1-1/2 million persons who have taken first -aid and mine rescue training courses . That these efforts over a period of 3 decades have been successful is revealed by the decline in coal - mine fatality rates and a somewhat smaller decrease in metal - mining and quarrying fatality rates .

Apr 1, 1943

By J. Bruce Clemmer

In the experimental concentration of Vermont talc-magnesite ores, talc concentrates and tailings rich in magnesite were obtained. On account of the possible market value of the magnesite, the tailings are given consideration' in this report along with the talc. After some comments about the talc industry, the magnesite that accrued as tailings will be considered. Then the flotation results will follow.

Jan 1, 1936

By T. A. Rickard

The key-note of good writing, as of good manners, is B natural. Sincerity is the first requisite for effective writing. When a man says what he knows or believes, he is likely to be interesting, because each human being possesses an individuality, a point of view, or a range of sympathy that makes him different from his fellows. To say or to write what you do no6 think, for the mere sake of talking or writing, is a verbal exercise that must be performed with extraordinary skill if it is to be attractive. Affectations are rarely attractive, rarely effective. To be natural is to be yourself, not a poseur; to give the reader the best of yourself, instead of re-warming the baked meats of yesterday. Quotations-which are second-hand thoughts-will serve occasionally when the thing you want to say has been said so well by another that it would be waste of energy to try to say it better; but, as a rule, the utterance of the writer himself is more interesting than the quotation, because the writer brings something of himself to bear on the subject, and for the moment is more in touch with the reader than any dear departed author. Therefore, say things as best you can in your own way, neither in borrowed words nor in the phraseology that mimics another. Write as if you were speaking to a person whom you desire to persuade or convince. You will then write better than you speak, because, in the first place, you can be more deliberate, and, secondly, you can revise what you have written. Speaking and writing are similar mental acts, with a difference: the difference between eating food raw and eating it cooked. Some kinds of food gain nothing by being cooked; likewise some kinds of utterance are not bettered by being written down first; but most expressions of thought, especially

Jan 1, 1931

By E N. Isaev, L E. Levin

New data on the geology of the Late Jurassic to Holocene sediments cover of the World and associated mineral resources (oil, gas, ferromanganese nodules, ores of massive sulphides and other metals) have been compilled in the Atlas at scale 1:25,000,000 and 1:10,000,000. The work was performed by scientists from four Institutes of Russia (VNIIzarubezhgeologia, VNIIoceangeologia, Vernadsky Institute of Geochemistry and Analytical Chemistry of theRussian Academy of Sciences and Geological Institute of the Russian Academy of Sciences). The Atlas shows variation of thickness and formational composition of the large complexes (Upper Jurassic-Early Cretaceous, Upper Cretaceous Eocene, Oligocene-Neogene, Pliocene-Pleistocene), distribution of oil/gas and ore deposits in each complex, data of deepsea drilling (leg 1-130),  thermo-pressure condition in the sedimentary basins within Circum-Pacific Rim.

Jan 1, 1995