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By Bodnaras G. E, Sceresini P. A

The Filblast Cyanidation Process incorporates the advantages of intense high shear mixing, high dissolved oxygen concentration and high pressure to achieve extremely rapid gold dissolution rates. This is made possible by the unique design of the Filblast gas shear reactor. The reactor is a rugged and compact in-line device. The outer casing is protected by a polyurethane coating and the internal parts are of wear resistant polymer. The largest unit built to-date has overall dimensions of 1200 mm length by 300 mm diameter and has a capacity of 150 dry tonnes per hour at 40 - 45 per cent solids. Service life at this throughput is at least three months. The process may further be applied to high temperature leaching of refractory gold ores or other metals. Wear resistant metal or ceramic materials would be employed for this duty. Four mines are currently employing the Filblast Process for treating a variety of ore types ranging from highly reactive, almost impossible to treat, pyrrhotite/arsenopyrite to deeply weathered clay ore which forms a highly viscous pulp. The effect of shear thinning has resulted in improved adsorption kinetics resulting in higher carbon loading and reduced soluble gold loss. Total tonnage treated is approximately four million. Operating costs which include leasing and maintenance charges for the Filblast and pump power costs are about 16 cents per tonne. This is equivalent to about ten per cent of savings. Laboratory scale units having capacities up to 30 litres/min are available for test work but laboratory testing techniques so far developed do not accurately reflect the oxygen and cyanide savings which have been achieved in the plant.

Jan 1, 1994

By Clinton H. Crane

IN October, 1925, J. R. Finlay delivered an address entitled, "The Future Price of Lead." Lead was then selling at 8.85c. and Mr. Finlay and most of the rest of us were concerned about the shortage. Now, a little more than six years after, lead is selling for 3.55c., and nobody is worrying about the difficulty of getting plenty of it. For 1931 the U. S. G. S. reports United States produc¬tion as 390,000 tons of recoverable lead in ore. Our estimate is slightly higher than this; nearer 400,000 tons. This is the smallest production since 1911 and 1912, but in spite of this, stocks for the year-have increased nearly 50,000 tons. Our estimate for the production outside the United States is 1,120,000 tons, or more than double the production of either 1920 or 1921, and 30 per cent more than in 1913. Stocks abroad probably have not increased more than stocks in the United States. In other words, foreign consumption is double what it was in 1.920-21, whereas domestic consumption is substantially less. It looks as if Mr. Krueger, president of the Swedish match trust, was right when he said that "This country had better stop worrying about Europe and think a little bit more about its own affairs."

Jan 1, 1932

By Henry Louis

IT can scarcely be considered a matter of doubt, in the present state of our knowledge, that the existence of, at any rate, two well-marked allotropic modifications of gold can be recognized, namely (a), the ordinary, yellow variety, and (b) the red, brown or purple, non-lustrous, amorphous variety. There are, indeed, not wanting indications that still other allotropic forms may be capable of existing. It is, for instance, possible that the green colors of gold obtained under certain conditions, or the black powder produced when the alloy of gold with potassium is decomposed by water, may represent further allotropic modifications, although this proposition is open to doubt. It call scarcely be pretended that the two first-named varieties have been absolutely isolated, yet it is, perhaps, quite permissible to speak of the ordinary and the amorphous modifications as having a proved existence. Ordinary gold is sometimes found crystallized in nature, although never in a state of purity. When gold is melted and, cooled slowly, its surface shows crystalline markings, and the fact that it is capable of crystallizing in the cubic system may be looked upon as established. When gold is produced by precipitation, the form which it assumes is dependent on the conditions of precipitation. G. Rose 1 says that gold precipitated by ferrous sulphate from very dilute solutions is so finely divided that no regular form can be recognized, but in more concentrated solutions the precipitate consists of minute cubes. When oxalic acid is used as a precipitant, the gold is coarser and forms octahedral crystals. J. Thomsen 2 has obtained similar results. Working with dilute and with highly-dilute

Jan 1, 1913

By J. McD. Porter

IN many of the old placer-mining districts are still to be found large tracts of gold-bearing gravel not suitable to be worked with a dredge, because the bed is too shallow- or the gulch too narrow. Frequently there is not enough grade to handle the gravel successfully by ground-sluicing or a bedrock flume, or it contains too many boulders to be worked successfully with the ordinary pipe or tube hydraulic elevator. In southwestern Oregon, two practical placer-miners named Ruble, after working for years trying to make money out of placer-ground containing many large boulders, invented and patented a hydraulic elevator of an entirely new type, and one . that has been found to work very successfully in flat' ground and in gravel containing many large boulders. It is a very simple contrivance. A few years ago I acquired the property near Pierce City, Idaho, known as the American placer-mine. Various attempts .bad been made to work this ground. A bed-rock flume had been installed by one company, an Evans elevator by another, and still other methods were tried on a smaller scale. All were unsuccessful. I installed a Ruble elevator, and it has proved very satisfactory. Working under 100-ft. (pipe) head, the 'ground has been handled at a cost of a little less than 8 cents per cubic yard. The conditions at the American mine are exceptionally hard, the boulders being large, heavy, and numerous. Basalt-boulders, up to a size of 16 by 18 by 32 in., have been elevated to a height of 16 or 17 ft., with a 4-in. nozzle-stream, under 100-ft. head. Boulders larger than this size are blasted. At the American mine, a foreman, two pipemen, and two laborers are-required per day of 24 hr. to operate the elevator. Several sizes of this elevator are in use, the one at the American mine being the 25-ft. size, having 25 ft. of grizzly

Oct 1, 1909

By Edgar Bain

IN STUDYING the structural characteristics of martensite it is desirable that a clear conception of the material from which martensite is produced should first be obtained. Any theory of its formation and structure incompatible with the facts of its parent substance, austenite, can be eliminated with little consideration. Austenite is the name applied to solid solutions of carbon and other elements in gamma iron. At temperatures above about 900° C. (1650°, F.), pure iron exists in a system of crystallinity1 entirely different from the crystal structure below that temperature. This high-temperature allotrope of iron is of an atomic structure associated with great ductility, having very manifold symmetry and an abundance of easy slip planes. The exceptionally ductile and malleable metals (gold, silver, platinum, copper, aluminum, and nickel) have this same atomic arrangement-the face-centered cubic. The low-temperature allotrope of iron, alpha iron, the solid solutions of which are known as ferrite, has a body-centered cubic arrangement of atoms. Like it, in crystal structure, are the less ductile and malleable metals, molybdenum, tungsten, titanium and chromium. Fig. 1. shows the two atomic arrangements known in iron; the diagrams are drawn to scale. Either of these modifications of iron may dissolve other elements in the solid state; by so doing, the temperature of the transformation is changed. In general2-7, it appears that a solid solvent metal dissolves a metal solute by substituting foreign atoms in its own space lattice. Thus, iron may dissolve nickel in either of its crystalline forms by permitting an atom of nickel here and there to occupy the normal position

Jan 2, 1924

By K. Mayhew, K. Murray

The CESL Copper Process was developed as a hydrometallurgical alternative to smelting and refining for copper sulphide concentrates. As the majority of such concentrates contain appreciable gold and silver values, effective recovery of these metals is essential to the economics of this technology. Unfortunately, conventional cyanide processing cannot be used on the residue from the copper process, clue to its unusual characteristics when compared with naturally occurring gold and silver ores. An abundance of elemental sulphur, as well as the presence of cyanide soluble copper, leads to the formation of both thiocyanate and copper cyanide which is detrimental to process economics clue to excessive cyanide consumption. This, however, can be reduced to acceptable levels by process innovations such as pressure cyanidation and cyanide recovery. This paper outlines the successful application of the CESL Gold Process to various gold-bearing copper concentrates from bench to demonstration scale.

Jan 1, 2011

By J. E. Rowland

NIOCALITE is a new mineral species which has been identified in rock from the Oka district, Quebec. It occurs as prismatic crystals up to l 0 mm. in length and I mm. in width, in coarse, white, crystalline calcite with associated apatite, diopside, biotite, pyrochlore, and niobian perovskite. The crystals of niocalite are light yellow in col-our and have a vitreous lustre. The optical properties of niocalite (I) are as follows: Biaxial negative -2V = 56° a = 1.700, [ ] = 1.730 Birefringence y -a = 0.030 Optic orientation: X = b, Z/\c 12°, Y , /\a = 32° The specific gravity is 3.32 and the hardness is approximately 6 (Mohs scale). A detailed analysis performed on 2.4 gm. of hand-picked material reveals that niocalite is essentially a calcium niobium silicate. Table I gives the result of the analysis. Crystals of niocalite, apparently suitable for X-ray diffraction work, were selected, and single crystal photographs were obtained using both Weissenberg and Precession cameras. Initial difficulties were encountered in interpreting these films, and in correlating the crystal data with the optical data. The in-consistencies were explained by the fact that every grain examined was twinned to some extent.

Jan 1, 1957

By W. A. Mudge

This discussion will be limited to malleable, commercially pure nickel and some high-nickel alloys, containing more than 50 per cent of nickel, which are produced by The International Nickel Company, Inc. at its Huntington works, West Virginia, from electrolytic nickel or from a nickel-copper sulphide matte. The principal sources of nickel are sulphides of nickel, copper and iron, which are found in the large deposit of pyrrhotite-pentlandite-chalcopyrite ores in the Sudbury area of Ontario, Canada. Pentlandite, a complex nickel-iron sulphide, is the nickel carrier. These ores are concentrated, roasted, and smelted to remove considerable iron and sulphur and to produce a nickel-copper sulphide matte. Separation of the component sulphides of this matte, followed by electrolytic refining, results in the production of electrolytic nickel and electrolytic copper; direct refining of a selected portion of the matte gives the nickel-copper alloy, Monel. FUNDAMENTAL OPERATIONS Melting of the metallic materials is done in natural gas-fired, acid furnaces of the open-hearth, or reverberatory, type, having capacities of 6 to 20 tons; in three-phase, basic, electric-arc furnaces, having capacities of 7 to 20 tons; and in basic, high-frequency induction furnaces having capacities of ½ to 3 tons. Malleable, commercially pure nickel is melted in the acid open-hearth furnace. The charge is sulphur-free, electrolytic nickel, containing 99.9 per cent nickel* and clean mill scrap. Monel, containing approximately two thirds nickel and one third copper, is produced by roasting the nickel-copper sulphide matte to an oxide, smelting the oxide with charcoal in a 20-ton, acid open-hearth furnace, adding clean mill scrap, duplexing to a 20-ton, basic, electric-arc furnace, and refining in this furnace with a lime-fluorspar, carbide slag. Inconel, containing nickel, 80 per cent; chromium, 14 and iron, 6, is melted in the 7-ton electric-arc furnace or the 3-ton induction furnace. The charge is electrolytic nickel, ferrochromium and clean mill scrap. These are the fundamental operations. High-nickel alloys are produced from one of these three materials by additions of suitable amounts of manganese, aluminum, silicon or copper. For example, the age-hardenable alloy, K Monel, is produced from Monel by the addition of approximately 3 per cent of aluminum, and D nickel is produced from nickel by the addition of approximately 4.5 per cent of metallic manganese. For conversion to rods, bars, sheet, strip, tubing and wire forms, by hot-working and cold-working operations, the molten materials are teemed into ingots ranging in size from 14 by 14 by 60 in., 3300 lb., to 36 by 36 by 48 in., 18,000 lb. All ingots are overhauled mechanically before hot working.

Jan 1, 1946

FROM north to south activity is picking up through- out the Labrador Trough-already shown to be one of the world's great iron ore provinces. Center of current activity and interest lies in the mid-southern part of the trough as drills, equipment, and . . . money start to pour into the area near Mt. Wright and Wabush Lake. First major announcement in the area came early this spring when J&L and CCI outlined an estimated billion-ton deposit for "future" operations. Later impetus came from rumored railway for US Steel's Quebec Cartier projects in the Mt. Reed area slightly to the south. As this issue went to press US Steel's request for bids on railway and hydroelectric construction, plus IOCC's decision to step up the time- table on its program in the Wabush Lake area east of Mt. Wright, triggered a flurry of other announcements involving many of the top U. S. and Canadian iron ore firms. Do not look for most of these place names in the average atlas . . . they aren't there yet, but they soon will be.

Jan 6, 1958

By Wittenau, E.

OPERATION of a pilot mill of 100 tons' daily capacity during 1930 and 1931 proved that the copper minerals of the Colorado and Clay sections of the Morenci ore body could be successfully concentrated by the flotation process. Economic conditions caused postponement of further testing work until late in 1938 when the former No. 6 Concentrator at Morenci was converted into an experimental mill of 1500 tons' daily capacity which was known as the Test Concentrator. The Test Concentrator began continuous operation on April 3. 1939, using such crushing and grinding equipment of the No. 6 Concentrator as was appropriate. Modern classifiers and certain flotation machines were installed and later other types of flotation machines, a large grate-type grinding mill. mechanical screens, a short-head cone crusher, and a disk filter were added to the test equipment. Operation was uninterrupted until Dec. 31, 1941.

Jan 1, 1942

By R W. Shaw

The MTM Process targets treating lower grade and/or problem concentrates that are not attractive to smelters. The process has been developed at laboratory scale for copper and is based on a related development for zinc that has been extensively developed both in the laboratory and through pilot testing. The basis of the process is novel ammonia-ammonium chloride leach chemistry adapted to give high copper extraction whilst being selective over iron, arsenic and many other elements. The preferred flow sheet depends on location, especially infrastructure and utilities. These impact upon the leach and crystallisation stages more than copper reduction.

Aug 24, 2022

By Roy A. Grancher

Construction materials indeed face a dilemma...as does the building industry as a whole. A stop & go economy; a severe drop; in housing starts; lingering indecision over just what corrective steps are to be taken or to their degree of commitment; no less basic disagreement in regard to which of the, Nation's problems is really the most pressing -- inflation or recession? Optimism has become a rare quality these days. At moat the cautious view is that this new year will see a long, hard struggle back, with hopes that 1976 at least can truly mark a dual anniversary celebration for the United States and its economic health. Yet the paradox is that once recovery does return, those very construction minerals and materials --which in recent years have experienced the ups and downs of overcapacity, shortage, and now declining demand again-- will once more face the spectre of mass inability to service revived and growing needs for its product. Mounting costs, present marginal expansion investment, and substantial lead times required for new facilities to come into production, could well form a bottleneck to economic upswing. The result again can be another cycle of shortage-induced inflation, and with it continued gyrations within the demand supply relationships of the country's building industries.

Jan 1, 1975

By X Ma

Kaolinite is of very fine particle size in nature and thus its dispersion plays a key role in the successful removal of kaolinite in iron ore flotation and selective flocculation processes. As the most widely used dispersant in the world, sodium silicate has been used as a standard dispersant for kaolinite in the iron ore industry. However, the actual effect of sodium silicate on the colloid stability of kaolinite particles and its dispersion mechanism remain unknown in the literature. In this work, the dispersion effect and dispersion mechanisms of some common inorganic and organic dispersants, including sodium silicate, polyphosphate and a low molecular weight polyacrylic acid, on kaolinite particles were systematically investigated through electrophoretic mobility and colloidal stability studies over a wide pH range. It was found that sodium silicate-kaolinite interactions only take place in the neutral and acidic pH range, while polyacrylic acid and polyphosphate interact with kaolinite from pH 3 to 10.5. Consequently, sodium silicate only disperses kaolinite at neutral and acidic pH. In contrast, polyacrylic acid and polyphosphate disperse kaolinite from pH 3 to 10.5, with strong dispersion effect observed at neutral and acidic pH. In the iron ore industry, selective fl occulation and reverse cationic fl otation, the most widely used flotation route, are both conducted at pH 10 to 10.5. The results of the present study show that, at such high pH, polyacrylic acid and polyphosphate are more effective dispersants of kaolinite, in comparison with sodium silicate.

Jul 11, 2011

By Andrew Ritter, Victor I. Montenyohl, Stephen R. Winzer

Thirty-seven open pit production blasting operations have been monitored using high-speed cameras running between 500 and 7000 frames per second. Analysis of the resulting films reveals irregularities in timing including sequencing errors and crowding (holes firing less than 8 ms apart), confirming results of laboratory testing of ms delay blasting caps (Winzer, 1978). Where blasting parameters are otherwise constant and within recommended guidelines (stemming, spacing, burden, etc.), timing problems dominate the overall performance of the blasting operation. Model tests in layered Homalite 100, designed to simulate joint or bedding planes in rock, indicate the importance of the stress waves generated by the explosive in developing the crack network which is ultimately responsible for the fragmentation seen in the resulting muckpile. These mechanisms are strongly supported by high-speed film studies at Pinesburg, Maryland. Experiments in controlling relief in deep shots (where depth approaches the lateral extent of the bench blasted) using borehole geometry and hybrid initiation systems (electronic timer and pyrotechnic delays) were carried out. The results suggest that the 1 me/ft. of burden guideline developed by Bergmann et aI., 1974 is too short, and that much longer times are necessary to optimize fragmentation and muck digability. Longer times are found to reduce noise, vibration, and flyrock.

Jan 1, 1979

By W. M. Corse

W. M. CORSE,?Mansfield, Ohio.-The conservation of tin, in view of the shipping situation; is one of great importance. Several methods of conservation can be employed: 1. Reduction of the amount of tin in an alloy or compound. 2. Substitution of an entirely different metal or compound for tin. 3. A combination of the first and second methods. The second method is the one that I wish to discuss. Metallic aluminum has been known for a long time, and its use in copper alloys was discovered about 1855 by Lord Percy. The high cost of production of metallic aluminum retarded its commercial development, and it was not until the discovery of the electrochemical processes for its production that it came to be known as a common metal. I have been particularly interested, for the past few years, in working with the alloy known as aluminum bronze, which is usually composed of approximately 90 parts of copper and 10 parts of aluminum, by weight.

Jan 12, 1918

By S. H. Chauvenet

HARRISBURG is situated on the Pennsylvania Railroad, one hundred and five miles from Philadelphia, two hundred and forty-eight miles from Pittsburgh, and ninety miles from Baltimore, and has running through it the Pennsylvania, Northern Central, Philadelphia and Reading, and Cumberland Valley Railroads, and the Pennsylvania Canal. Surrounded by a thickly settled farming country, from which to draw native labor, within easy distance of anthracite and bituminous coal, with ores and limestone near at hand, and with the Susquehanna River as a never-failing water supply, Harrisburg has advantages for manufacturing which warrant the investment of the capital that has already been made, and has a future as a manufacturing city second only to Pittsburgh and Philadelphia. THE PENNSYLVANIA STEEL COMPANY, L. S. BENT, SUPERINTENDENT. The works of this company, the largest in Harrisburg, lie between the Pennsylvania and the Philadelphia and Reading Railroads, on. the Pennsylvania Canal, and are essentially devoted to the manufacture of Bessemer steel rails. Capital stock, $2,000,000; invested in business, $5,000,000; wages per month, $80,000; employs 2000 men; capacity, 100,000 tons of rails per year, which is being increased to 130,000 tons. The plant, as it now stands, comprises five Bessemer converters, two 7-ton and three 8-ton converters, two 15-ton open-hearth furnaces in operation, and two 30-ton open-hearth furnaces in course of construction, one blooming mill, one rail mill, seven steam hammers, two blast furnaces in operation, two blast furnaces in course of construction, foundry, pattern $hop, machine shop, blacksmith shop, and frog shop, and merchant mill in course of construction. Bessemer No. 1 was built in 1865, with two 7-ton converters, 2 spiegel cupolas, 3 feet diameter, and 3 iron cupolas 6' 6" diameter,

Jan 1, 1882

By J. M. Paxton, R. L. Roscoe, G. A. McCreary, W. W. Muir, T. J. Drown, D. A. Barr, T. W. Law

"This paper reviews the complete cycle of a small mining operation in a remote section of northern British Columbia, including discovery, exploration, development and production. The discovery of high-grade epithermal gold-silver mineralization occurred in 1969 following a regional geochemical reconnaissance program designed to search for porphyry copper mineralization in the Cassiar-Omineca Mountains. Exploration and development from 1971 to 1979 included geological, geochemical and geophysical surveys; trenching, almost 30 000 feet of surface and underground drilling in about 100 holes and cross-cutting, drifting and raising on the principal goldsilver- bearing vein. This led to the delineation of 100000 tons at an estimated grade of0.9 oz gold per ton and 18 oz silver per [on to an average depth of 120 feet below surface. of a 100-ton per day mining operation employing about 50 personnel with all supporting infrastructure transported to the site by a Hercules aircraft. The operation was subsequently supported by its own Twin Otter aircraft with periodic Hercules campaigns supplying major items including fuel.The mining operation included both open-pit and cut-and-fill methods. The milling operation employed conventional cyanide leach process with cyanide destruction initially by alkali chlorination and subsequently by the Inco SOl /Air process.The fly-in operation, initially structured on a 21-day-in and 7-day-out basis was modified to al-t-day-in and Z-day-out basis with no loss in efficiency and with a significant increase in employee satisfaction. The operation, which earned the B.C. Small Mines Safety A ward in two consecutive years in its Ll-month operating history, emphasized safety and process hazard awareness. Wildlife studies in the environmentally sensitive mine area also showed that industry and wildlife can coexist in harmony.Most importantly, the paper compares the feasibility assumptions with actual operating experience."

Jan 1, 1986

By Raymond E. Zimmerman

Abstract-The Swirl Cyclone developed in Japan, although based upon the same principles as the standard cyclones for heavy-media or water-only cyclones for cleaning coal, is novel in that it is invested with the apex on top, discharging rejects at the top, and clean coal at the bottom. It also uses a variable air vent tube for controlling the vortex. Tests conducted indicate that its efficiency is not only as sharp as standard cyclones but it also performs using a much coarser grain magnetite, promising higher magnetite recovery. The author describes the results of tests conducted in Japan on a very difficult coal.

Jan 2, 1978

By Douglas Ragland

Two subjects certain to incite interest among a few practicing engineers and almost all engineering educators are professional recognition and decline in engineering enrollments. It is not surprising that this interest on the part of the educators is universal; it is only regrettable that such an interest on the part of the practitioners is not more widespread. In fact, it is probably the hope of the profession that some of the more penetrating searches now being made into the nature of engineering will generate sufficient cause for perplexity that members of the profession will assume a significant degree of personal concern toward purely professional matters.

Jan 1, 1963

The Sage Mill Project w approved by Santa Fe Pacific Gold Corporation's Board of Directors in October 1994. The Sage Mill Project included a pressure oxidation plant designed and constructed to process refractory carbonaceous ore using fine grinding/autoclaving technology developed specifically to treat Twin Creeks ore. The project was constructed in two phases. The first phase was put into operation on May 5, 1997, just hours before the transfer of ownership to Newmont Gold Company occurred. The second phase started in October 1997. This paper reviews schedule, costs, scope changes, and methodology used on the project that spanned almost five years from project definition through commercial operation.

Jan 1, 1999