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By Rixford A. Beals

It has been observed with considerable accuracy that if the major U. S. mines were moved to Mexico tomorrow, many of them would be losing money. But the companies would continue to operate, losses or not, because they would have to. And some of the newest and most promising low grade ore projects in the U. S. would never have "gotten off the ground" had they faced the equivalent of the mining taxes now in effect in Mexico. No one of the various mining taxes in Mexico seems prohibitive by itself. Taken together, on the balance sheet, however, the picture changes. Production and export taxes alone take from 20 to 40 pct of the gross product value for base and precious metals.

Jan 2, 1955

By Gordon A. Gross

Banded siliceous manganese-iron bearing sediments recognized as distinctive facies of Algoma-type iron formation constitute low-grade resources of manganese in many countries. Manganiferous facies associated with oxide and carbonate facies of iron formation have iron to manganese ratios ranging from 0.2 to 2 and commonly about one. Manganiferous facies up to 30 m thick occurring separately or with other iron formation facies are associated with cherts, carbonates, shales, turbidites, tuffs, and lavas. Primary cherty manganiferous facies and their gondite metamorphic equivalents represent significant manganese resources and are protores for higher-grade deposits derived by secondary enrichment processes.

Jan 1, 1983

By Donald C. Myntti

Modern open-pit mining can be described as a capital-, labor-and energy-intensive, large-scale, mechanized, and highly repetitive bulk material preparation and handling operation, with emphasis on the word "mechanized." In hard rock, this generally means shovels loading blasted materials into haulage units for transport to processing plants, stockpiles, or waste dumps. Mine management deals with several primary concerns on a daily basis; e.g.: Will any serious accidents and labor problems occur today, and will the tonnage targets be met considering the physical condition of the equipment? The latter subject will be discussed from a maintenance perspective. A successful, progressive heavy equipment maintenance program that protects company assets involves many elements. They include: •Proper equipment selection and procurement •Well-trained and motivated workforce •Good shop facilities •Preventive maintenance (PM) program •Warehouse support •Operations-maintenance department cooperation •Meaningful paperwork

Jan 3, 1978

By J. C. M. Li

This exploratory survey was undertaken to repeat some experiments- in which anomalous results were reported1 for bismuth and to measure the thermoelectric power of some bismuth alloys and inter-metallic compounds. sato1 reported that the thermoelectric power of bismuth depends on the temperature gradient. This seems rather unreasonable especially when the Benedicks effect' has not been detected. Even if the material is not homogeneous, the observed thermoelectric power can be represented by

Jan 1, 1959

By George A. Komadina

The Pima mine lies 20 miles southwest of Tucson, Ariz., and 45 miles north of the Mexican border. It is located on a hillside overlooking Tucson, which allows for gravity flow generally through the plant. In April 1965, an expansion was authorized by the mine's board of directors. This will triple the mine's output to 18,000 tpd. At this rate, it is estimated that there is sufficient ore to last 20 years.

Jan 6, 1965

By Graham Crutchfield

THE W. I. Cook pool in Shackelford County, Texas, has been the subject of a number of papers and articles. Its unique position both as to operation and development has made it an ideal location for unit repressuring. The major portion of the pool is located on the W. I. Cook ranch and most of the oil leases are owned by Roeser & Pendleton, FIG. 1.-PRODUCING SAND CONTOURS, COOK POOL, JAN. 1, 1931. Inc. and the Continental Oil Co. and operated by Roeser & Pendleton, Inc. The Humble Oil & Refining Co. and Tom James operate producing leases which have a vital bearing on the unity of the pool. Both have cooperated in the repressuring project. Practically the entire royalty is .owned by Mrs. W. I. Cook and she has given the operators her entire cooperation in all phases of unit repressuring.

Jan 1, 1931

By W. D. Lacabanne

DRILLING fluids as an aid in drilling holes into the earth have been in use successfully for more than a half a century. Originally used in a primitive fashion in water well drilling before the turn of the century, drilling fluids came into their own in 1901 when they were incorporated as an indispensable part of the newly invented rotary oil drilling method. Since drilling fluids have been the basic factor in successful modern oil well drilling, at- tested by the dramatic growth of the U. S. petroleum industry, their study and development have naturally taken place in the oil industry. An abundance of engineering and scientific literature has appeared on the subject of drilling fluids. Application to Exploration Drilling The drilling fluid system is understandably called the heart of the rotary oil drilling rig. Any other type of rotary rig, such as the diamond drill, should benefit by the incorporation of mud fluids in the drilling scheme.

Jan 12, 1954

By Seishiro Hirakawa, Hiroshi Tokunaga, Hironori Nakamura

Two unique processes of reclaiming zinc from various secondary materials were developed and have successfully been operated for years by Mitsui Mining and Smelting Co. These processes were established based on the characteristic and local energy conditions; i.e., (1) at Miike Smelter, located above the largest coal deposit in Japan, a combination of slag fuming and semi-blast furnace (MF)processes takes advantage of using coal and the carbon bearing briquette residue from the vertical retort plant as reducing agents, (2) on the other hand, at Kamioka Smelter, a direct reduction of zinc-bearing lead slag by using electric furnaces is of advantage in view of cheap electric power supply from our own hydraulic power plants. The former also consumes lots of zinc bearing fines and drosses from various steel plants, fabricators and secondary zinc smelters, while the latter, zinc leach residue from its own electrolytic plant

Jan 1, 1976

By Howard M. Wells

The investment worth of a mineral deposit can only be realistically evaluated in relation to specified engineering design criteria which fully detail the proposed method of exploitation. The operational design of a mine falls essentially within the technical discipline of the mining engineer, under the constraint that the technical design should be aimed at optimizing the financial attractiveness of the project. In the case of a marginally viable proposition it becomes vitally necessary to identify the best set of design parameters which together will add up to an optimum investment proposal. This paper examines some fundamental logic of optimization for a "wasting asset" type of investment such as a mine, with special reference to the rate of annual production and the strategy of selective mining.

Jan 1, 1979

By John R. Reynolds

Mercury has long been neglected in American mining industry. The plights of domestic producers have been many and their compensations few. The mercury market has been dominated in the past, as it will be in the future, by the Spanish and Italian producers. Other major producing countries are Yugoslavia and Mexico. Probably no other mineral commodity has fluctuated so much in price. A 76-lb flask of mercury sold for $195 in 1943, $76 in 1948, and $325 in 1954. This wide fluctuation has resulted in spasmodic domestic production. U. S. mines produced 51,929 flasks in 1943, and only 4535 flasks in 1950. In 1955 the estimated production was 18,400 flasks. Domestic consumption in 1955 was 57,200 flasks.

Nov 1, 1956

By L. Massé, Th. Koulomzine

NOTE ON HAALCK'S FORMULA QUANTITATIVE interpretation of magnetic anomalies is admittedly a difficult process. Few authors have attempted a general approach to this problem. A [ ] number of publications can be found widely scattered through scientific periodicals, which present particular solutions obtained by the introduction of simplifying assumptions, such as the reduction to an equivalent magnet or pole, or the hypothesis of a very thin vein. The practical applications of these solutions are necessarily very restricted though they have given satisfactory results in isolated cases. Probably the most widely known equation of this type was given by Haalck.l His classic work contains curves calculated for typical conditions, and has now become a standard reference. However, a close scrutiny of Haalck's derivation reveals that, aside from the hypothesis of a thin vein, it rests on the

Jan 1, 1947

By J. Leja, J. H. Schulman

FROTH flotation is usually effected by the addition of a collector agent and a frothing agent to an aqueous suspension of suitably comminuted mineral ores. The action of collectors is to adsorb onto the surfaces of minerals to be separated, sensitizing them to bubble adherence. The action of frothers has, in the past, been accepted as that of froth formation only, brought about by a lowering of the air/water interfacial tension. Substances capable of producing froth are classed1a,b according to their relative capacities for production of froth-volume and froth stability in the simple frother-water system. The purpose of this paper is to show that the surface active agents acting as frothers become effective only when there is a suitable degree of molecular interaction taking place between collector molecules and frother molecules at the air/water and solid/ water interfaces. Further, the discussion will demonstrate that the actual mechanism of adherence of an air bubble to a suitably collector-coated particle is due to the molecular interaction collector-frother. This leads to the formation of a continuous interfacial film of associated molecules, anchored to the mineral by polar groups of the collector, and enveloping the whole bubble. The tenacity of adhesion mineral-to-bubble results from the strength and the visco-elasticity of this mixed film. Some 20 years ago Christman2 postulated mutual dependence of collector and frother in effecting flotation. This view was, however, strongly opposed by Wark,3 who pointed out that an addition of frother had no effect on the value of contact angle once this was established in the solution of collector. More recent work by Taggart and Hassialis' indicated that the presence of frother, namely, cresol, leads to the immediate establishment of a contact angle on sphalerite, partially coated with xanthate, whereas an air bubble fails to make contact in potassium ethyl xanthate solution alone, even after 60 min induction time. Wrobel5 raws attention to the selectivity of frothers in flotation. Many instances of antagonistic effects of certain mixtures of frothers (or collectors and frothers) on flotation froth have been known to flotation operators and have been reported in literature. Taggart6 and Cooke7 give several examples of incompatibility of certain ratios of frothers and collectors, e.g., oleate and long-chain sulphates, pine oil and soaps. Monolayer Penetration. Properties of insoluble films produced by molecules of surface active agents orientated at the air/liquid interface are conveniently studied by the Langmuir trough technique, described fully by Adam.' Using the trough technique Schulman and Hughes" and Schulman et al.10a. b, c, d,e established the existence of molecular interactions occur- ring between certain types of surface active agents. Their experiments revealed the phenomenon of penetration of an insoluble monolayer (e.g., a film of a long-chain alcohol) by a soluble agent (e.g., sodium alkyl sulphate) injected into the substrate (water or salt solution). The degree of molecular interaction taking place on penetration is determined by changes in the surface pressure of the resulting film, changes of its surface potential and its mechanical properties (viscosity and rigidity). When the interaction takes place between both polar groups and both hydrophobic groups of the two participating amphipathic molecules a molecular complex is formed. Complexes formed on penetration of the monolayer at interfaces are not necessarily true chemical compounds: they are labile in solution, the activity and reactivity of individual components are greatly different from those of the molecularly associated complex, and on crystallization they usually separate out into components. However, when formed in the orientated state at interfaces they are found to be very stable, although some mixed films spread as monolayers of stoichiometric complexes can show further penetration by subsequent additions of the soluble component injected into the substrate.'" The degree of association between two or more types of surface active agents is very sensitive even to small changes in electric (dipole) moment of the polar groups of the amphipathic molecules as influenced by magnitude and position of neighboring ions or dipoles, their size, concentration, and stereochemistry. In addition, the molecular association is greatly influenced by concentration and type of inorganic salts in the substrate, by its pH, and by temperature. The nonpolar groups of interacting molecules greatly affect the stability of molecular complexes. Progressive shortening of the aliphatic chain of one of the reacting molecules weakens (at an increasing rate) its tendency to form stable complexes. Similarly, introduction of a double bond of cis-form into one of the reacting chains, which changes the straight hydrocarbon chain into a kinked one, or introduction of a branched chain, reduces the stability of the associated complex. Monolayer Adsorption. Using the trough technique and injecting metal ions into the substrate (water or salt solution) underlying insoluble films of fatty acids, alkyl amines, and sulphates, Wolsten-holme and Schulman11a,b,e. ' and Thomas and Schulman" have established conditions, namely, pH, concentration. and steric factors, under which molecular interactions take place between the polar groups of the surface active agents and the metal ions. These interactions are marked by great changes in the solubility and mechanical properties of the monolayer of the agent; no surface pressure increases are observed as in monolayer penetration experiments. The results of these adsorption studies, correlated with flotation experiments, indicated that in the case of fatty acids and alkyl sulphates their adsorption onto minerals of base-metals takes place by a similar

Jan 1, 1955

By George Beavers

FLASH roasting of iron concentrate is in the experimental stage at Copperhill. The problem is peculiar in that the iron concentrate is predominantly pyrrhotite; the ratio of that mineral to pyrite being 5 to 1. Results so far indicate that the heat, generated in roasting a material containing 52.0 per cent iron and 38.0 per cent sulfur, requires special handling and for this reason the installation costs per ton of roaster feed may be too great to compete with hearth roasting. Interesting features of flash roasting at Copperhill are: 1. The sulfur dioxide content of the roaster exit gas can be varied between wide limits. Eight per cent sulfur dioxide gas, with 1.30 per cent sulfur in the calcine, has been common practice and gas up to 13.0 per cent sulfur dioxide has been possible. 2. Temperatures of the exit gases are very high. When roasting 60 tons or more of iron concentrate per 24 hr. in a modified Wedge roaster, the temperature in the roaster rises to 2000° F. and the calcine is lowered to 0.20 per cent sulfur. If the entire roaster system could be constructed to withstand such temperatures, ideal roasting conditions would obtain as regards sulfur elimination and tonnage roasted.

Jan 1, 1934

By Charles Fulton

The study of the condensation of zinc from its vapor was undertaken to shed light on certain problems encountered in large-scale electric zinc-furnace work recently conducted. It is a matter of common knowledge that one of the disadvantages of the arc type, electric zinc furnace, is the production of a large amount of blue powder and proportionately little liquid spelter, for, as stated by Stansfield,1 "A notable defect in the electric smelting of zinc ores is the difficulty experienced in obtaining the distilled zinc in the liquid state; when zinc ores are smelted electrically, very little liquid metal is commonly obtained, nearly all of the zinc being in the state of powder."

Jan 8, 1918

By T. Sterry Hunt

I HAVE already referred to this interesting locality in the opening address, but at the request of some of the members of the Institute, brought before them specimens of the ore and the accompanying rock. The ore, which is cassiterite, is also met with elsewhere in Maine, at Paris and Hebron, but it there occurs associated with orthoclase, quartz, tourmaline, and beryl, in concretionary granite veins, which cut the micaceous gneisses of the White Mountain series. At Winslow the veins traverse an impure gray micaceous limestone, which is found in many parts of this region, and is subordinate to the same gneissic series. The veins, which are seldom more than an inch or two in thickness, are abundant through a considerable breadth of the rock, and are interlaminated with it, occupying places between the sedimentary layers, which are distinctly marked by different shades of color. Occasionally, however, they cut across the stratification for a little distance, showing that the disrupting action was not always confined to tearing the layers apart. The vein-stone consists of purple fluor-spar, and silvery white mica with quartz. In this gangue the cassiterite, nearly black in color, is disseminated in small crystalline masses, sometimes one-half an inch in diameter, and is associated with a little mispickel. I have only seen the veins as exposed at a single point, but was informed that similar veins holding the ore are met with at a distance of several thousand feet

By A. Lee Barrett

The Maintenance Committee of the Coal Division of the American Institute of Mining and Metallurgical Engineers is presenting with this report the first of a series of cost comparisons which it plans to present the Institute. The plan is to assemble maintenance cost on all equipment connected with mechanical operations at the face of coal mines, to arrange these costs by districts, to make comparisons between districts, and within districts. This particular report covers data with respect to mobile loading machines, including both "on-track" and "off-track" equipment. It is anticipated—in fact, considerable data have already been accumulated—that next year complete maintenance costs by districts can he presented for complete loading units, including the various classes and combinations of on-track and off-track equipment. Data have also been collected with respect to some phases of maintenance methods and certain recommendations of the committee are included dealing with maintenance problems. In the assembly of these data more than 120 questionnaires were sent to operating companies throughout the United States. At the time the report was written 33 questionnaires had been returned with completed information and an additional group of companies had written that the information requested was not at present available but that they hoped to have such information available in the not far distant future. The replies as

Jan 1, 1947

By A. Lee Barrett

The Maintenance Committee of the Coal Division of the American Institute of Mining and Metallurgical Engineers is presenting with this report the first of a series of cost comparisons which it plans to present the Institute. The plan is to assemble maintenance cost on all equipment connected with mechanical operations at the face of coal mines, to arrange these costs by districts, to make comparisons between districts, and within districts. This particular report covers data with respect to mobile loading machines, including both "on-track" and "off-track" equipment. It is anticipated—in fact, considerable data have already been accumulated—that next year complete maintenance costs by districts can he presented for complete loading units, including the various classes and combinations of on-track and off-track equipment. Data have also been collected with respect to some phases of maintenance methods and certain recommendations of the committee are included dealing with maintenance problems. In the assembly of these data more than 120 questionnaires were sent to operating companies throughout the United States. At the time the report was written 33 questionnaires had been returned with completed information and an additional group of companies had written that the information requested was not at present available but that they hoped to have such information available in the not far distant future. The replies as

Jan 1, 1947

CENTRAL EMERGENCY COMMITTEE Chairman, MRS. H. N. SPICER As no further requisition will be Made for knitted garments, for the boys of the 27th Engineers, all completed garments and wool have been collected and returned to Mr. W. R. Ingalls, and the activities of the

Jan 12, 1918

By A. L. Field

Bureau of Mines Technical Paper 189 consists of a record of the scientific data obtained in the iron blast-furnace slag investigation which is reported in Technical Paper 187, "Slag Viscosity Tables for Blast-Furnace Work." It includes a description of the method of preparing the synthetic melts, construction of an improved electric furnace, and refinements in laboratory methods of measurement. Only the general features of the work and the conclusions drawn from the experimental data can be given attention here. Silicates in the Liquid State In the manufacture of refractories, Portland cement, glass, and porcelain, and in pyrometallurgical operations, importance attaches to the behavior of silicate compounds at temperatures beyond the range of common experience. This field of research has not been investigated as carefully as its scientific and industrial importance would seem to warrant. Probably the most important of the unsolved problems in the, chemistry of silicates is the question of their stability in the liquid state. That little progress toward the solution of this problem has been made is not strange if there be borne in mind the difficulties attending experiments made at temperatures at which silicates become fluid, and the comparatively short time since it became possible to measure these temperatures. On the other hand, considerable progress has been made in the study of the compounds in the solid state because of the directness and simplicity of methods of optical examination.

Jan 12, 1917

By P. K. Kaiser, C. Mackay

A circular shaft with a diameter of 6m was excavated by the conventional drilling and blasting method to a depth of 235m through 60m of glacial till, 1 Om of water bearing basal sand, 1 1 Om of clay shale (Bearpaw Formation) and finally a strata of coal, mudstone, siltstone and sandstone (Oldman Formation). The lined shaft was instrumented at three levels by multipoint extensometers to determine the displacement field near the shaft bottom, embedment strain gauges to measure the strains in the liner and IRAD-stress change gauges to observe the radial and tangential stress changes in the rock mass. The data from these gauges were used to determine the in situ stress field. An attempt to measure in situ stresses by overcoring was also made at a higher elevation. The performance of the shaft and its support was then evaluated by use of the "Convergence-Confinement Method". For this purpose the measurements of stress changes and displacements were combined to determine by extrapolation the displacements ahead of the shaft and after the liner installation. The convergence curves calculated in this fashion were then used to evaluate the performance of the cast-in-place concrete liner and of an alternate shotcrete shaft support system.

Jan 1, 1983