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ARSENIC and orpiment are two mineral substances of a similar kind, and they are by nature pure, without admixture of other species. In regard to their apparent qualities we shall say that their composition is scorched, well-purified earth; and because of a certain subtlety and easy digestion they penetrate very easily into fused metals, indeed they act in such a way that they corrupt and convert almost into another nature any metal with which they find themselves. Orpiment and arsenic act in almost the same way as do tin and mercury. With these the fraudulent alchemists blanch copper, brass, and even lead to the whiteness of silver. According to the physicians they are in fourth part hot and dry. They are also corrosive because of certain powers; indeed, they are a most powerful poison to the life of all things. Arsenic is found in white and citrine colors. Orpiment seems to be a separate thing, although both are formed in the same ore and both are in lamellae or scales. These lamellae or folds are thinner than paper, in fact

Jan 1, 1942

The smoker, Monday evening, was an unusual success. It was held in the beautiful gold room of the Congress hotel, which was very elabo-rately decorated with American flags. More than 500 were present. The gallery was filled with ladies, who responded to the request of the song leader and helped in many ways to grace the occasion. The enter-tainment, was a varied one and was original with the Chicago Committee, which deserves great credit for the unusual success of the event. Al-though it was mostly funmaking, Dr. F. B. Cottrell and George S. Rice of the Bureau of Mines gave some very interesting talks, illustrated by flags and moving pictures, of their trip through Europe since the armis-tice. Mr. Rice's talk dealt particularly with the demonstrative coal and iron regions and Doctor Cottrell's was devoted almost solely to that part of his trip in Northern Italy where he was investigating the application of volcanic steam to power purposes. This steam is derived from boracic-acid springs and helium is secured as a byproduct.

Jan 11, 1919

By David Hall

IN October, 1926, the Inspiration Consolidated Copper Co. began the operation of its new leaching plant, which has a capacity to handle 8600 dry tons of ore daily and produce therefrom approximately 160,000 lb. of electrolytic copper per day. (See Fig. 1.) The energy for the leaching process is supplied by three motor generator sets (Fig. 2), each set consisting of one 5450-hp., 6600-volt, three FIG. 1.-LEACHING PLANT OF INSPIRATION CONSOLIDATED COPPER CO. AT INSPIRATION, Ariz. phase, 25-cycle, 500-r.p.m. synchronous motor and two 1920-kw., 150 to 320-volt, 6000-amp.,12-pole, d. c. generators, and one 70-kw., 125-volt d, c. exciter. The capacity of the three sets is 36,000 amp. at 320 volts. A description of the metallurgical processes of this plant was. given in a paper by H. W. Aldrich,1 and from his paper we quote the following figures for the month of July, 1927:

Jan 1, 1928

By Joseph Cervik

INTRODUCTION Common methods of controlling gob gas in U.S. mines are by means of ventilation of gob areas and gas drainage through surface boreholes. Costs of drilling surface gob holes increase as deeper coal- beds are mined. Where gob holes cannot be drilled because of topography, ventilation is the only means of control. Even then, sufficient air may not be available to dilute methane in the bleeder entries to acceptable levels. Thus, new methods of gob gas control need to be developed that are independent of surface topography, and of the mine ventilation system, and less costly than present systems. Except for slight variations in procedures and equipment, Great Britain, West Germany, France, Belguim, Poland, and Czechoslovakia use a common methane control method that is different from the system generally used in the United States. This Bureau of Mines paper reviews European mining methods, mining conditions, and methane control technology and discusses their applicability to U.S. mines.

Jan 1, 1981

By Frank Ittner

In this section it is proposed to discuss operating methods considered good practice under the various field conditions commonly encountered. Efficient field direction and types of equipment needed to meet transportation problems are considered only to the extent that the desire to produce the best possible records must sometimes give way to the factor of cost. As in all engineering projects, alternative possible methods of operation must be considered in the light of relative costs as well as of the quality of results obtained, Cost may be in the background of much that is done in the field operations, but only the effect on record quality will be considered here. Record quality at a particular shot point may vary with the various factors of spread character (relative positions of geophones and shot point), shot-hole depth, formations opposite position of shot, size of charge, the effect of repeat shots, surface geology and culture in the immediate vicinity of the geophones, recorder instrument characteristics, particularly filter.

Jan 1, 1940

By Frank Ittner

In this section it is proposed to discuss operating methods considered good practice under the various field conditions commonly encountered. Efficient field direction and types of equipment needed to meet transportation problems are considered only to the extent that the desire to produce the best possible records must sometimes give way to the factor of cost. As in all engineering projects, alternative possible methods of operation must be considered in the light of relative costs as well as of the quality of results obtained, Cost may be in the background of much that is done in the field operations, but only the effect on record quality will be considered here. Record quality at a particular shot point may vary with the various factors of spread character (relative positions of geophones and shot point), shot-hole depth, formations opposite position of shot, size of charge, the effect of repeat shots, surface geology and culture in the immediate vicinity of the geophones, recorder instrument characteristics, particularly filter.

Jan 1, 1940

By David H. Y. Tang, Syd S. Peng

In general, the strata sequence of the immediate roof in the under- ground coal mine openings can be divided into three types. They are: (A) each stratum deflects independently, (B) some stratum (or strata) loads on the underlying stratum, and (C) each stratum loads on its underlying stratum. The flexural behavior of the immediate roof which is made up of multiple strata not only depends on the material property, geometry, and external loading of rock strata, but also on the strata sequence. A computer program based on the beam-column theory is written for determining the bending stress and deflection for the generalized immediate roof. The flexural behavior of the immediate roof in various strata sequences are investigated for the following effects: roof span, horizontal stress, thickness and Young's modulus of the lowest stratum. In addition, some of the results are compared with the results of the finite element method.

Jan 1, 1983

By Aaron J. Miles, Eugene A. Stepenson

The pressure distribution in a producing oil or gas reservoir has been obtained mathematically in a limited number of special cases where the boundary of the reservoirs are simple geometric figures with the wells conveniently located within them. Using some of the previous work as a basis, it can be proved that a number of additional problems of pressure distribution can be solved by use of soap film. This method is particularly applicable to a reservoir drained by a number of wells, or to a reservoir of irregular shape, or to both. Since this method obtains the pressure distribution, it also establishes the drainage boundaries of the wells. This paper derives the analogy between the equation representing the pressure distribution in a reservoir and the equation of the deflected membrane. It also describes the apparatus and the method of operation. The experimental method is employed to solve a problem whose mathematical solution is known and the results compared. These are found to be in good agreement. The method is applicable to any homogeneous liquid, compressible or incompressible, or to a gas, flowing in a reservoir of uniform thickness, permeability and porosity. The flow state may be either the steady state or the transient state wherein the density or pressure of the fluid in the reservoir declines at a constant rate. PRESSURE-DISTEIBUTION PBOBLEM Fluids encountered in the oil reservoir are compressible and expand and move toward the drilled hole where the Dressure is lowest. The loss of fluid from the reservoir lowers the pressure in the more distant parts of the reservoir, permitting the fluids in these parts to expand and move toward the well. The area around the well affected by drainage is increasing continuously, and the density, pressure, and velocity of flow

Jan 1, 1938

By Gail Moulton

THE oilfields in Illinois are located principally along the LaSalle anticline in the southeastern part of the state. The oil produced comes most largely from beds of Pennsylvanian and Mississippian age, but there is an increasing important production from deeper horizons, as will be noted under new development. The oil is largely of paraffin base, and has an average specific gravity of about 35° Baume. The rank of Illinois as an oil producer has dropped from third since 1913, when its production was exceeded only by that of California and Oklahoma, to eighth in 1923. This has been the result of failure to find new pools of considerable size to offset the declining production of the old wells and of the greatly increased production of some of the other states. The noteworthy features of petroleum production in Illinois during 1924 are: the low rate of decline for the state as a whole; the smaller percentage of dry holes; and the larger average initial yield of the new wells.

Jan 3, 1925

By Ta M. Li

In Gila County, Ariz., the Jaquays Mining Co. still finds the mining of asbestos a worthwhile and economical venture. At a time when domestic productive capacity is being reduced because of rapidly rising costs and tough environmental dust standards, this firm has dramatically brought its mine and mill operation into full productive capacity and compliance with both Federal and State regulations. Jaquay's Mining Corp. owns four underground mines in the Tonto National Forest, located approximately 32 miles north of the Globe-Miami District in Arizona. Only one mine, the El Dorado, is presently active. It mines an estimated 45,000 tpy of ore and waste. From this figure about 3000 tpy of fiber (No. one crude to Grade 4T) and fiberized shorts (No, seven) are recovered at the firm's mill, located in Globe, Ariz. Based on current ore reserves, the El Dorado mine has an estimated life between 15 to 17 years, assuming current mining rates and stable market conditions.

Jan 3, 1975

By L. J. Trilli

RECENT studies have indicated that there may be considerable difference in the cleanliness of the central pipe cavity of open top ingots. It has been speculated that some of this difference arises becausk of reactions that occur during reheating in the blooming mill soaking pits. In this respect, it has been recognized that an oxide coating or flow of slaggy material in the cavity could inhibit welding during hot rolling and thus reduce the amount of sound product which may be obtained. This note is intended to summarize some observations on the structure of a split ingot top which may be useful in describing a mechanism whereby the shrinkage cavity could be oxidized during reheating. A 221/2x241/2 in., big-end-down, test ingot was secured from a routine production heat. The chemical analysis representing this ingot is as follows: 0.08 pct C, 1.04 pct Mn, 0.062 pct P, 0.315 pct S, and 0.02 pct Si. The deoxidation practice used on the heat from which the experimental ingot was

Jan 1, 1957

By D. W. Fuerstenau

Locked-cycle grinding experiments on mineral mixtures provide a means to study circuit performance in simulated continuous grinding systems. Such experiments with calcite/quartz mixtures revealed that approximately twenty-five 2-minute cycles are required before the composition of the circuit product and the recycle material attain steady state. The circulating load, after steadily increasing during the first 15 cycles, continued to fluctuate over a narrow range. Previous batch ball mill grinding of mineral mixtures has shown that breakage rate functions of minerals are time- independent but composition-dependent. In the closed-circuit grinding of ores with constituents having different grindabilities, the grinding rate parameters for the components also would therefore change during the transient period. With fluctuations in feed composition occurring randomly every half to one hour in processing plants, it is quite likely that the grinding circuit can be in unsteady state perpetually. The significance of these observations is discussed in this paper in the con- text of the models used in control schemes for the grinding circuits

Jan 1, 1984

By M. C. Fuerstenau

Each year during the AIME Annual Meeting, the MBD Division has its Business Meeting. Because many members cannot attend, it has be- come policy for the secretary of the Division to present highlights of the business conducted at the Meeting in Fine Grind. This year the Meeting was held on March 1 in the Americana Hotel. Five major items of business were brought up for discussion. These were: (1) the proposed name change for the Division, (2) institution of the Taggart Award, (3) a name change for a Unit Committee, (4) MBD funding of scholarships, and (5) authorship of Fine Grind articles. The Matter of What We Should Call Ourselves A lively discussion was held on the issue of a name change for the Division. Two names have been proposed: (1) Mineral Processing Division, and (2) Mineral Engineering Division. A number of strong reasons for changing the name from Minerals Beneficiation Division have been pointed out. Perhaps the most important of these is that the term "beneficiation" does not describe all of the functions that engineers in our Division perform. Further, there are inherent problems associated in the term, in that beneficiation is a long word which has the twofold disadvantage of being both difficult to pronounce and difficult to spell.

Jan 1, 1971

Dr. Oldshue has provided a useful summary of a voluminous subject and my task will be to select and direct attention to those areas of mixing theory and practice which are germane to mineral processing in general, and to fine particle treatment in particular. Pulp mixing in impeller actuated reactors occurs in mineral processing in several different applications: (1) emulsification of reagents; (2) mixing pulp with 'reagents as in conditioning for subsequent operations (such as flotation, flocculation or agglomeration) ; (3) high intensity agitation, as in (a) disintegrating and dispersing aggregates, and (b) aggregating particles as in shear flocculation or in selective agglomeration; (4) hydrometallurgy; (5) hydrometallurgy with gas phase (e.g., Arbiter process); . (6) flotation in sub-aeration machines. Attention is invited to 3 above in which two opposite effects can be induced by proper choice of chemical treatment and hydrodynamic conditions. Successful processes for treating mineral fines require excellent aggregate dispersion in order to fully accomplish the liberation stage. Some processes depend further upon selective aggregation following dispersion. The term “dispersion” is often used in different senses which for present purposes will be clarified at the bottom of the next page.

Jan 1, 1979

By A. U. Seybolt

DURING the course of an investigation of hot corrosion of nickel-base superalloys (combination oxidation-sulfidation attack at high temperature), it was considered possible that sulfur might gain entrance to the alloy in part, at least, by diffusion through the scale. Cr203 is nearly always observed as a prominent component of the oxide scale, and hence some experiments were carried out to examine the tracer diffusion of sulfur through Cr203 at 1000° C in the upper temperature range experienced by jet engine blades and vanes. Some hot-pressed Cr203 discs of quite high density were available from an earlier investigation1 on the rate of crf3 migration through Cr203. The Cr203 was 99.3 pct pure and contained -0.06 pct Fe as the largest metallic impurity. Additional data is given in Ref. 1. In this earlier work it was found that the rate of cation diffusion was independent of the atmosphere of thermal equilibration when using nitrogen, argon, or air, and also that the electrical conductivity of the hot-pressed Cr203 compacts was likewise independent of atmosphere in this range, thus indicating that the de-

Jan 1, 1969

By D. F. DeSante, A. S. Tetelman

MICROCRACKS are often introduced into commercial metals during fabrication processes such as swaging, cold rolling, deep drawing, and welding. These microcracks act as strain concentrators and may be capable of causing premature catastrophic failure of a component or weld. The present investigation was undertaken to determine whether high-temperature annealing treatments may be capable of reducing or negating the detrimental effects of such existing microcracks. Internal microcracks, ranging from 0.1 to 0.85 mm in length and averaging 0.23 mm, were introduced into polycrystalline Fe-3 pct Si tensile specimens (0.155 mm grain size) by the cathodic charging of hydrogen.1'2 The typical appearance of such microcracks and their associated strain patterns (made visible by the technique of dislocation etch pitting3) is shown in Fig. 1. The stress fields of the dislocation loops formed during plastic relaxation stabilize the microcracks so that, when the internal hydrogen pressure is removed: the microcracks stay open, rather than disappear as perfectly elastic cracks would be expected to do.' As shown in Fig. 2, such stopped microcracks cause a 36 pct decrease in the macroscopic cleavage fracture strength at -196°C.

Jan 1, 1969

Preamble At the present time many bodies are engaged in -the formulation of standards. There is no uniformity in the rules for such procedure in the different organizations; in some cases the committees engaged in the work are not fully representative, and in. a considerable proportion of cases they do not consult all of the allied interests. The present custom results in a considerable duplication of work, and in some fields several "standards" are proposed for the same thing, differing from one another only slightly and often in unimportant details. It is very much more difficult to obtain agreement between the proposers of overlapping standards after they have been published than it would be to get the proposers to agree before they had committed themselves publicly. The American Institute of Electrical Engineers, the American Institute of Mining Engineers, the American Society of Civil Engineers, the American Society of Mechanical Engineers, and the American Society for Testing Materials have appointed a committee to consider the advisability of cooperating in engineering standardization. This committee recommends that these societies form a permanent organization by appointing a committee as proposed in the following constitution and rules of procedure to carry on this very important work.

Jan 3, 1918

By AIME

Cores must be cut in half to secure workable samples for saturation, porosity, and permeability tests. They come from the field labeled as to the type of core, well, and depth from which they came.

Jan 1, 1948

By R. Hogg

INTRODUCTION The principal applications of the flocculation process in the coal industry lie in the area of waste water treatment. Consequently, the concern is more with the behavior of the associated minerals, clays for example, than with the coal itself. At the same time, however, the presence of even small amounts of fine coal can significantly influence the performance of the flocculation operation. Coal preparation waste water treatment is a substantial problem involving over 200 billion gallons of water annually. There can be no doubt that these quantities will continue to increase as coal production increases and environmental considerations dictate the increased use of closed circuit systems and tighter control of effluent quality. Furthermore, we can expect to find a continued increase in the amount of fines generated in the coal mining and processing operations. Modern mining techniques tend to yield a finer raw coal with a higher ash content. The greater emphasis on fine coal cleaning for improved sulfur and ash removal and increased coal recovery will also lead to greater demands being placed upon the wastewater treatment system. The costs of "blackwater" treatment have been shown to vary widely from plant to plant (1). Part of this variation can be attributed to differences in the coal being mined and the plant flowsheet but there are no doubt significant contributions from the improper design and operation of treatment facilities.

Jan 1, 1980

By H. T. Byck

THE plastering properties of six representative California drilling muds were studied over a temperature range of 70° to 175° F. at several mud weights, using a high-pressure circulating filter press with full size consolidated cores. In all tests, with untreated as well as with chemically treated muds, the filtration rates at elevated temperature were higher than at low temperatures and in nearly every case this increased filtration rate was notably larger than could be attributed alone to the decreased viscosity of water-the flowing medium-at elevated temperatures. It is concluded that no existing method will permit even an approxi-mate determination of the filtration rate at high temperature from data at room temperature. It is necessary to measure filtration at the tem-perature actually anticipated in the well, or to make a sufficient number of tests at various lower temperatures so that a small extrapolation of these data to the anticipated well temperature may be applied. Such tests should be carried out on the mud as actually used in the well. The viscosity of each of the muds was determined over the same temperature range. While no relationship was observed between mud viscosity and plastering properties, it was found that chemical treatment of the muds for viscosity reduction shifted the temperature of minimum viscosity to appreciably higher values than for untreated muds.

Jan 1, 1939