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By Abderrafih Guessous

INTRODUCTION Morocco is an important lead-zinc producing country: 120,000 tons of lead concentrates were produced in 1968. Zinc ore production is less, 67,000 tons of concentrates in 1968. Most of the present production comes from three districts (fig.1) (i) Touissit-Bou Beker district, in the eastern part of the country, close to the border with Algeria. (ii) Aouli-Mibladen district, in the central part of the country. (iii) Aouam district, about $0 miles south of Meknes. In the first district lead and zinc are always found together. The two other districts produce mainly lead. This paper will be limited to a short description of geology and mining methods in the three aforementioned districts. More detailed geological informations can be found in the symposium on lead-zinc deposits in Africa (1).

Jan 1, 1970

By P. R. Sheorey

Understanding of in situ rock mass behaviour has taken a step forward with the advent of the refined rock mass classifications of Wickham, Bieniawski and Barton et al. In this paper six case studies are given in brief showing how Barton's classification could be used in mining situations. The cases cover stability of roadway junctions under shallow covers, support pressure estimation in roadways in intact and failed rock conditions, determination of the safe unsupported span of a wide stope and estimating the stability of roadways in two contiguous seams standing 011 small pillars against puncture of the parting rock.

Jan 1, 1983

By J. D. Irving

In the summer of 1899 there appeared in the Black Hills Mining Review† a short note announcing the discovery of certain deposits of wolframite in the vicinity of Lead City and Yellow creek, Lawrence co., South Dakota.

Jan 1, 1902

By John J. Elango

Strain gage load cells, the most widely used type of nonmechanical weight sensor, are capable of taking measurements between 0.45-4.5 million kg (1-1 million lb) with an accuracy of 0.05%. They are available in a wide range of standard capacities, configurations, and accuracies, and special load cells may be custom-manufactured to meet unusual requirements. Typical applications include automated batch processing, process monitoring and control, mixing of powders and liquids, weighing coal or other materials in silos, and in large platform systems that weigh trucks and railcars. Because the strain gage load cell produces an electrical signal proportional to the applied load, it readily interfaces with readouts, keyboards, computer terminals, and alarm systems.

Jan 6, 1979

By Joseph Bernhardt

Use of concrete underground at No. 4 mine, Cornwall, Pa., has become increasingly important. Starting with small amounts at finger openings, occasional raises, piers, its use has expanded to entire slushing drifts and haulages. Besides eliminating costly timber repairs, concreting costs of slushing drifts have proved cheaper than timbering. Higher haulage-concreting costs are offset by no maintenance charges during the life of the haulage.

Jan 3, 1950

By S. W. Hazen

The use of operations research and computer techniques continued to expand during 1967. A number of mining companies either obtained computers or were experimenting with their use through service bureaus. This trend was also evident in the Canadian mining industry. Although the annual Symposium and Short Course on Computers and Operations Research in Mineral Industries was not held in 1967, technical periodicals like MINING ENGINEERING, Mining Congress Journal and Engineering and Mining Journal stepped up their coverage on the subject. The annual AIME meeting had eight papers in two sessions and one session on Operations Research was held at the SME Fall Meeting in Las Vegas.

Jan 2, 1968

By E. A. H. Tays

As I promised, in a former paper on the Bryan Mill,* to give further data regarding the plates from four battery-aprons, I now submit the following: These aprons were 4.5 feet wide by 16 feet long; the first two plates of each apron were 4.5 by 4.5 feet, and the remainder of varying sizes, as can be seen by their relative weights, as shown in the table; but all were 54 inches wide. They were in use 4 years and 9 months, and about 15,265 tons of ore passed over each. The ore was quartz, carrying about the same weight in silver as in gold; showing some copper, and highly impregnated with ferric oxide. The tailings show about 0.6 per cent., and the bullion about 10 per cent., of copper. The silver was present mostly as sulphide; and the copper was also present as sulphide, with some carbonate. The ore treated ill 1898 was a fair average of the whole run; so I take it as an example from which to make a few deductions.

Jan 1, 1901

By Jon E. Fatzinger

The design of a centrifugal slurry pump is approached as a compromise between efficiency and wear life of the wetted parts. This compromise is effected by the choice of proper materials of construction and geometry. However even the most optimally designed pump will fail if due consideration is not given to its installation and operation. System head curves and hydraulic profiles are discussed as useful tools to be used in the operational analysis of a slurry system.

Jan 1, 1978

By William Hamilton Merritt

At the Atlanta Meeting in October, 1895, a short paper was presented by Mr. R. W. Leonard on the " Assay of Auriferous Ores and Gravels by Amalgamation and the Blow-pipe" (Trans., xxv., 645), embodying the results of some very conclusive tests as to the value of the process. His arguments regarding the desirability of the process appear to be indisputable, but the practicability of the field-outfit used by him is open to question. The Province of Ontario, in which Kingston is situated, is still largely unexplored; and at the Kingstoil School of Mining we give much attention to the instruction of prospectors and the testing of ores. To this end, not only is there a small mill (to which Mr. Leonard alludes) attached to the school, but prospectors' classes

Jan 1, 1897

By G. B. Richardson

WHILE examining a number of curves showing the production of petroleum, the author was impressed by the rather uniform relationship between the cumulative production from the beginning of development FIG. I.-ACTUAL' AND COMPUTED PRODUCTION OF PETROLEUM IN WEST VIRGINIA. down to the time the peak was attained and the estimated total production. The curves examined showed an average ratio of cumulative peak production1 to total production of approximately 30 per cent. FIG. 2.-ACTUAL AND COMPUTED PRODUCTION OF PETROLEUM IN CAT CREEK FIELD, MONTANA. These relations were discussed with C. E. Van Orstrand, geophysicist of the Geological Survey, who investigated the subject mathematically.

Jan 3, 1925

By T. C. Craig

During the year 1936, there were 654 oil wells drilled in the Texas Panhandle, with a total daily initial production of 256,049 bbl. Although 74 more wells were drilled than in the previous year, the total initial production lacked 109,303 bbl. to equal that of 1935. The explanation is that during 1935 most of the drilling was in the granite-wash area, which is much more prolific than the dolomite, in which the major development was done during 1936. Twenty-one oil wells were drilled deeper, increasing their potential 3683 bbl. The total daily oil potentid of the field Dec. 31, 1936, as determined by the Texas Railroad Commission, was 834,888 bbl., with a daily allowable production of 71,335 bbl. No overall field decline in production is recognized by the Texas Railroad Commission. A well is tested upon completion to determine its potential production. If the well is then shot with nitroglycerin or is treated with

Jan 1, 1937

Eckley B. Coxe, Drifton, Pa.: Anthracite coal differs from other fuels in its greater solidity. It does not burn like coke or wood, or like bituminous and coking coals, which become more or less spongy when heated, so that combustion can take place to some

Jan 1, 1892

By Chris Weyand

Throughout the past 40 years we have been drawing inevitably closer to the conclusion that coal will be our chief source of energy. Our reserves of natural gas and petroleum, on which we depend, are dwindling. Knowing that we will soon reach our physically extractable limit of these energy sources. The US government has created many incentives to encourage energy companies to transfer technology and resources from natural gas and petroleum to coal. Such encouragement is stimulated through taxation methods. Coal mining engineers deal mainly with production, which involves planning and design throughout the acquisition, exploration, development, production, and reclamation of a mine. Though taxation is not one of the areas analyzed by the engineer, it should be considered and understood as it is involved in the mine life cycle. This paper will discuss coal taxation in the five stages of mining and will explore certain tax saving decisions.

Jan 1, 1983

By K. Shoji, R. Hogg, L. G. Austin

The flow of dry powders through continuous ball mills has been investigated. Based on a physical model of the system, expressions have been derived which relate the holdup of material in the mill and its variation along the length of the mill to the mill dimensions, speed of rotation, material feed rate, and the mill discharge geometry. Experimental results obtained in a small (4 in.) mill using 3/8-in. steel balls and a feed of silicon carbide particles are in good agreement with the prediction of the model.

Jan 1, 1976

By L. W. Saperstein, J. C. Mills, L. B. Phelps

Selective placement of toxic mine spoil has been advocated as a means of reducing environ¬mental pollution at the source. However, methods of burial to control environmental damage are not well understood. Using the finite element method, this paper investigates the burial of toxic material within low permeability packages below the water table. The effects of differing package and spoil permeabilities, anisotropy, and infiltration are modeled to provide information about their effect on the flow system. Projections can then be made that will assist in the design of the toxic spoil package to limit the amount of ground water flowing through them.

Jan 1, 1986

By R. Malmstrom, H. Heden, K. Likin

Sublevel caving techniques at Luossavaara-Kiirunavaara AB (LKAB) in Sweden have undergone significant modification over the years as management strives to maintain mine viability amidst rising costs and erratic iron ore prices. LKAB, which is 96% state-owned, is Sweden's principal iron ore producer and operates three iron mines north of the Arctic Circle. By far, the largest of LKAB operations is the Kiirunavaara (Kiruna) underground iron mine which extracts an estimated 30 million t/y of ore, Other iron mines include the Malmberget underground nine, rated at 12 million t/y of ore, and the Svappavaara open-pit mine, rated at about 4.5 million t/y. Mined ores from Kiirunavaara and Svappavaara are shipped by rail to the northwestern harbor of Narvik, while Malmberget ores are sent to Lulea, located to the southeast. LKAB iron ores are marketed by Malmexport AB, which is owned jointly by LKAB and Granges, Sweden's base metal producer.

Jan 10, 1979

By John A. Church

The operations of the Tombstone Mill and Mining Company, in Arizona, have been extensive and interesting; and I will eudeavor to describe what is novel in their work, without attempting to go over the well-known facts of silver milling, concentration and smelting which are the general branches of their business. Their mines are at Tombstone, and their mills at Charleston, ten miles distant. The ore has been mined only above water-level, and at first was

Jan 1, 1887

By Robert A. Lothrop, Richard B. Porter, Robert P. Porter

Changes became necessary in dredging methods employed in Idaho through passage of the Dredge Mining Protective Act (1954). Among other provisions, the law requires dredge operators to construct settling ponds of sufficient capacity and character to reasonably clarify the water used in the mining process before such water is discharged into the stream. Porter Bros. Corp., a placer mining company with many years operating experience in Oregon and Montana, became interested in strategic mineral placers in Idaho in 1950 when it was learned that prospectors had discovered a radioactive mineral deposit in Bear Valley Creek, 95 miles northeast of Boise. The company acquired mining leases and proceeded with exploration and development work on the property. After extensive research had resulted in the determination of successful separation processes, contracts were negotiated with the federal government and deliveries of columbium-tantalum and uranium concentrates commenced in 1956.

Jan 5, 1960

By Randolph Specht

A two year study was made of the waste disposal of the pebble rock phosphate industry. Solid slimes are impounded in large settling areas and the process water is re-used. Clear effluent was not found to be toxic to fish or animal life in field tests or in controlled experiments.

Jan 7, 1950

IT is not necessary to enter into a long discussion of ordinary bells, because every master carpenter or blacksmith knows how to make those levers with a crossbar that are called storks. This is nothing other than a board that has a thick and heavy head and looks more like a dolphin than a bird. This has a long tail in the form of a handle so that it makes a more powerful lever. As can be seen in every bell tower and other place where there are bells, it has, crosswise above the point where the cannon of the bell is fitted and fastened in, an iron bar which is arched and which has its two ends turned horizontally. These are made round so that they may turn easily when they are held by two steel rings or in two metal grooves or on glass pillows. In this, the more the transverse rod is arched,

Jan 1, 1942