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Scraper With over 40 pet more struck capacity than previous models, the new Caterpillar No. 90 scraper is designed to increase earthmoving production when used with D8 tractor power. This scraper moves dirt with the aid of a hard surfaced, reversible cutting edge. Material is carried in a flat, doublebottom bowl of high tensile steel. Operation is by means [ ] of a cable-control unit, which can be mounted on the rear of the tractor to provide for positive loading and ejection. Tapered roller bearings are installed at each axle. The scraper uses two 24.00 to 29 front tires and two 27.00 to 33 rear tires, all four of 24-ply rating. When loaded, the scraper distributes 60 pet of the weight on the rear tires. Circle No. 1

Jan 1, 1952

By Ronald J. Roman, Craig Olsen

Alterations were performed on a previously developed heap leaching model representing sulfuric acid solution leaching of a malachite sandstone ore. The alterations were made in order to approach a more realistic solution to the leaching equations used in the model and to provide a means of obtaining a constant acid con- centration in the model' s simulated heap effluent solutions. This constant acid concentration is desired if the effluent solutions are to be treated in a solvent extraction-electrowinning plant. An economic study was made showing a use of the leaching model for an imaginary heap leach operation. The example illustrates a method of selecting heap leaching parameters if data are available on mining costs, dump costs, capital cost, etc. This was achieved using an incremental investment technique.

Jan 1, 1974

By Carlos Kovacs-Figueroa

Complying with air pollution regulations created the need to dispose of increased sulfuric acid production by the Morenci smelter. As a result, a two-module leaching plant was constructed to leach Morenci flotation tailings. The leaching plant was equipped to perform the following operations: leach feed pumping, agitated leaching, two-stage countercurrent decantation, neutralization of leached tailings, and copper precipitation. Ancillary facilities were provided for neutralizer and flocculant preparation as well as precipitant handling and recovery of precipitates. Plant control is automatic from a central control panel supervised on a shift schedule by one operator and two helpers. Construction of the first module was initiated in April 1973 and leaching of tailings commenced in November 1974. Construction of the second module began in January 1975 and was completed in November 1975.

Jan 1, 1977

By J. A. Herbst, J. L. Sepulveda, J. D. Miller

Effective bismuth removal from flue dust residues has been accomplished for flue dusts from both zinc and copper smelters. Selective dissolution of bismuth, with respect to silver and lead, can be achieved by the proper manipulation of temperature, sulfuric acid addition and sodium chloride addition. Optimum levels of these variables were determined using a response surface technique to maximize the objective function: Y = %Bi/(1 + %Ag). In the case of the flue dust residue from a zinc smelter, which contains bismuth as an impurity (0.05%), 86% bismuth removal can be realized with less than 1% combined silver and lead dissolution. Similarly, in the case of flue dust from a copper smelter, which contains bismuth as a primary constituent (3.3%), 93% bismuth removal was obtained with little dissolution of silver and lead values.

Jan 1, 1977

By T. F. Witherbee

The subject of an article in the Engineering and Mining Journal for October 13th, 1877, namely, Blast Furnace Treatment of Silicious Iron Ores,, is of great interest to myself, and doubtless to many others who hare been troubled with a seemingly unaccountable percentage of silicon in their pig iron. It is to be regretted that the author of the article did not give us complete details of his charges, and thus prevent a possibly fatal error in the very beginning of the discussion of the points raised in his communication. As it now stands, I think we will have to fall back upon the statement that, " every conceivable mixture of fluxes and ores (A and B) has been used." Let us first, in order to simplify the calculations, do with she

Jan 1, 1879

By H. Sato, I. Matsuoka, T. Kawai, S. Hasebe

In a limestone mine, a large amount of slime is washed off in order to remove impurities such as clay minerals. A fine sized calcite is, consequently, wasted and freight for carring the slime to reclaim land is expensive. The separation of calcite from the slime has been investigated by the flotation process, using sodium oleate as a collector. A satisfactory flotation of calcite from the slime requires great amounts of sodium oleate, because sodium oleate is consumed by clay minerals. But, the amounts of sodium oleate required are reduced to half by adding suitable amounts of sodium silicate. After rougher and cleaner flotation, the concentrate containing more than 97% calcite is obtained with 70% recovery; thereby the amount of slime to be reclaimed is reduced to 40%.

Jan 1, 1976

By J. C. Holm

Although the main constituents of Portland cement are the oxides of calcium, silicon, aluminum, and iron, characteristics of the cement are seriously affected by such contaminants in the raw materials as magnesium, phosphorus, sodium, potassium, sulfur, and others of lesser importance. Sources of cement raw materials comprise a long list of minerals occurring in nature in various degrees of purity. The calcareous raw materials are generally limestone of purity varying from calcite to cement rock (a low-grade limestone of natural, almost correct chemical composition), chalk, marl, seashells, coral, and coral sand. The argillaceous raw materials supplying silicon, aluminum, and iron are mainly various forms of clay and shale, to which may be added silicious sand, iron ore, bauxite, or kaolin for minor adjustment of the chemical composition.

Jul 1, 1956

By S. A. Braley

THE first commercial production of bituminous coal in the United States was in 1820, and formation of acid in the areas from which the coal was removed began at that time. Thus it is 130 years since the development of mine acid began. The coal operator has had to deal with the acid water produced in his mines, and his losses from corrosion of pumps and equipment have been tremendous. Other industries and the public have been forced to spend large amounts for their water requirements because of the acid discharge from the mines. There are many contradictions in the literature on this subject probably because of variations in the analytical procedures followed and differences in the methods of calculation and reporting. The opinions previously expressed may be summarized as follows:

Jan 8, 1951

By M. J. Greaves, Alan English

Pelletizing on a commercial scale is only 10 years old; yet in this period more than 150 million tons of pellets have been produced. Instrumentation and controls have played an important part in the development of an entirely new industry in almost unprecedented time. Initially, most control circuits used in the pelletizing industry were manually operated, since the confidence factor in instruments and controls was quite low at that time. This changed considerably in recent years and improvements in the use of instruments and controls have probably developed more rapidly in pelletizing than in any other metallurgical process. Now, within a decade of the start of commercial operations, the use of manually operated controls has changed and consideration is being given to the utilization of computers for data logging and control purposes.

Jan 7, 1965

By Richard H. Ross

A broad definition of' "Mill Design" might cover everything from the first tentative choice of general process to the final structural details for construction. The first phases are mainly concerned with metallurgy and economics and the final stages with the mechanics of putting the selected equipment together into an integrated plant. It is the purpose of this article to discuss only data, derived from laboratory testing, that contributes directly to design of the milling plant itself, and only the plant design phases that are influenced by laboratory testing. Most ore beneficiation testing is devoted to determining recoveries, grades of products, elimination of impurities, reagent and supply requirements, etc. having little to do with physical plant design although these factors are of prime importance in the evaluation of a mining project.

Jan 3, 1964

Electrical requirements in surface mining can be divided into three categories: main substation, plant power, and pit distribution. A main substation may vary from a 500-kva transformer supplying 480-v power to motor-driven pumps and conveyors, to a 50,000-kva substation serving a large beneficiation plant or a large strip mining operation. Regard- less of size, it should be designed with the realization that a failure of the main substation will totally shut down the operation. Location of a main substation usually is a compromise between expense of running the incoming high-voltage transmission lines and the voltage drop of long secondary runs. Based on a geological survey for immediate and future areas of excavation, the main substation should be located as near to the center of load as possible.

Jan 10, 1967

By Richard D. Dick

The Los Alamos National Laboratory was involved in an oil shale fragmentation research program in cooperation with a Consortium of industrial companies to investigate the feasibility of using modified in-situ (MIS) recovery of oil from oil shale. Field tests were conducted at the Anvil Points Mine, Colorado, in the thick oil shale beds of the Green River formation. Part of the program included obtaining data about fragmentation by instrumenting the tests with accelerometers, velocity gauges, and the CORRTEX technique (Continuous Reflectometry for Radius versus Time Experiments). Some of the rock motion data from accelerometer and velocity gauges is presented, along with some conclusions. In addition, the signal recording system is briefly explained. The CORRTEX technique is discussed, and some results on explosive performance and stem behavior using the method are discussed.

Jan 1, 1984

By Eugene A. Stephenson

In November, 1932, Dr. Lacey, of the California Institute of Technology, presented before the American Petroleum Institute some of the results of his research under Project 371. The investigations described dealt particularly with changes in the physical properties of petroleum that result from the solution of natural gas therein. The solubility of Santa Fe Springs dry gas, containing 87 per cent methane, 8 per cent ethane and 5 per cent propane, had been determined in various crudes at 100' F., and 2000 lb. pressure per square inch as shown in Table 1 and Fig. 1 herewith. Originally the computations were made in terms of cubic feet per barrel, but' for a more uniform basis of comparison the results are also shown as cubic feet of gas2 per cubic foot of oil.

Jan 1, 1935

By J. J. Snodgrass

Faults, sandstone channels, and abandoned mine workings present severe safety hazards, disrupt mining, and necessitate costly precautions or discontinuance of operations. In addition to fault detection, mining companies have a need to map discontinuities such as seam thinning and previously mined areas in both longwall and room-and-pillar operations. Initial field tests demonstrated successful generation and propagation of higher order guided wave modes. Theoretical studies indicate potential for improved resolution by sensing small details in the coal seam and roof structure. Controlled-waveform source transducers and specialized detectors are particularly useful to preferentially excite and detect the Love (SH) and Rayleigh-type (P-SV) waves, including the higher frequency modes. The distinct observation of reflections using the transducers in the shear wave mode makes feasible the detection of the water-filled voids.

Jan 1, 1986

By J. Jay Jacobsen

A dynamic regional coal development model is constructed for the Eastern Powder River Basin of Wyoming. Using this model, alternative development schedules from a recent environmental impact statement submitted to the Department of the Interior are simulated (Ref. 1). These alternatives include different mixes of export capacity, different coal conversion techniques within the region, as well as various levels of coal production. Exportation of 70 to 80 percent of an ultimate coal production of 180 million tons (163.3 x l09 kg) per year and the careful phasing of additional public services with population growth effectively reduce the social and environmental impacts of coal development. The alternative involving the addition of 43,000 megawatts of electrical generation capacity has very significant adverse social and environmental impacts on the region.

Jan 1, 1977

By George L. Adams

There is an extensive literature relative to gas, oil, and the more solid hydrocarbons; but when it has all been digested and summarized, the resulting information is far from being satisfactory. The problems which have received the most attention are naturally those which relate to the successful exploitation and utilization of the deposits. From what is known of their geologic occurrence, theories have been formulated and rules laid down for the guidance of prospectors. The technology of the products has been made the subject of special chemical investigations. The geologic interrelation of the hydrocarbons, however, has not been considered in a broad manner, and the principles which have governed the origin of the economic bodies have been but imperfectly expressed. On the other hand, metalliferous deposits have been widely

Jan 1, 1903

By Wilbur T. Stuart

THE increased demand for iron ore has necessitated a re-examination of ore-bearing lands on which the presence of water previously has indicated hazardous and expensive operating conditions. In view of the importance of iron ore production to the national economy and defense, the Ground Water Branch of the U. S. Geological Survey, in cooperation with the state of Michigan, began a study of mine drainage in the Iron River district in 1945, and later extended the work to the Marquette district. The purpose of these studies was to define the principles involved in the movement of surface and ground water toward the mined areas, with the hope that the information obtained in the research would lead to the development of methods of water control and to a reduction in the total mining costs.

Jan 12, 1951

By John S. Alexander

DURING the past few years the block coal of Indiana has been talked about and written upon to such an extent, that almost every one at all interested in such subjects, has been made acquainted with the area and geographical position of the field, the quality and peculiar properties of the coal, the thickness of the veins, the manner of mining, etc. The writer, therefore, taking for granted that, to those present all this is familiar ground, desires more especially to call attention to the position this coal takes in the market, and at those points of consumption where it is brought in direct competition with rival fuels. Chicago, thus far, has been the chief consumer of Indiana block coal, the distance from the mines at Brazil, via Terre Haute and the

By E. D. Meier

SINCE Dr. St. Albans, in 1840, began to build successful watertube boilers—some of which are still in use—the gravity-return water-tube boiler has been built in many forms, more or less familiar to all who have studied the subject. A single firm in this country published recently a pamphlet, showing some fourteen modifications of their boiler during about as many years. There were hence available to the thoughtful inventor of this latest form many data showing what forms were to be avoided, as well as the effects sure to follow certain erroneous methods of construction in the older types. Improvements in materials, tools, and workmanship made possible, forms formerly prohibited by excessive cost. The first Heine boiler was built by A. Borsig & Co., for the

Jan 1, 1886

By M. D. Everell

A study has been made of the relationships between grinding selection functions and physical properties of rocks, particularly the failure loads of irregular particles and the compressive and tensile strengths of large regular specimens. The rocks used were limestones of various structures and impurity contents, a carbonatite, and a high-purity crystallized calcite. The selection functions were obtained from carefully performed grinding experiments on selected narrow size ranges in various grinding machines-a laboratory batch ball mill, a Hard grove grindability machine, and a mill of the type suggested by Yang, Mempel, and Fuerstenau. The specific rates of breakage during milling and the failure loads of irregular specimens correlated well for the rocks studied. The testing of irregular particles is suggested as a means of predicting the behavior of commercial mills.

Jan 1, 1973