Search Documents

By Young C. Kim

Abstract-The use of computer models to design the ultimate open pit limits during feasibility studies as well as during long-range mine planning is becoming an enforced Practice in all types of mining, e.g., ferrous, non-ferrous, and coal. As a result, the state of the art in computerized ultimate pit limit design methodologies and associated computing and optimizing techniques has advanced considerably in recent years. Unfortunately, very little has been published to date regarding the preferred ultimate pit limit design philosophy, i.e., optimizing m satisfying, or regarding the modeling approaches being used for different types of orebodies. This paper reviews the current state of the art in various modeling approaches and optimizing techniques that are in use for different types of deposits, through available literatures and personal communications.

Jan 10, 1978

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 Alan Hooper, James E. Mischler

Construction began in 1984 for a 5 megawatt hydroelectric power retrofit at the O'Shaughnessy Dam for the City of Columbus, Ohio. The construction necessitated excavation of limestone bedrock up to 27 feet below the normal water level of the river downstream of the dam. Proximity to the river and difficult terrain resulted in an interesting and challenging construction project.

Jan 1, 1986

Jan 1, 1948

By Harrison Souder

MAGNETITE mining and milling in the Eastern States showed continuing improvement during the year. Some of the smaller mines remained idle, but the larger operations responded promptly to the improved situation in the iron and steel industry. The output of ore for 1936 was over twice that for 1935. A number of improvements were made in mine plant and equipment, and operating forces were increased and maintained at near normal. The coming year should see additional mines started up and production increased at the larger properties.

Jan 1, 1937

By Charles C. Towle, Irving Rapaport

URANIUM mineralization along the north flank of the Zuni Uplift, in the vicinity of Haystack Butte, was discovered by Paddy Martinez, a Navajo Indian, in the spring of 1950. The find was reported to the Santa Fe Railway Co., which initiated a program of exploration upon its holdings in the district in December of 1950. The Anaconda Copper Mining Co. secured numerous leases in January and February, 1951, and began an intensive exploration and development program in March 1951. The district was extended into the Lucero Uplift in August of 1951 by the discovery of uranium mineralization in Todilto limestone by Joy Sinyella, a Supai Indian living on the Laguna Reservation. Initial reconnaissance was performed in the district by the Atomic Energy Commission in November 1950. A field office under the direction of the Denver Exploration Branch of the AEC was established at Prewitt, N. Mex. in January 1951 to study regional and detailed guides to ore, to evaluate the ore deposits, and to promote the development of the district by providing geologic services for the companies and individuals engaged in exploration. With the development of sufficient ore to warrant construction of a mill, the Grants area of New Mexico has come of age as a full fledged uranium mining district. The carnotite-type deposits of Grants, the first of major economic importance found in limestone, have extended the Colorado Plateau carnotite field into the more complex structure of the Basin and Range Province. General Geology The Grants uranium district is in northwestern New Mexico, along the southern flank of the San Juan Basin, between the cities of Gallup and Albuquerque. The region is at a mean altitude of about 6800 ft, vegetation is sparse, and outcrops are excellent. Mt. Taylor volcanic peak, at an elevation of 11,400 ft dominates the surrounding area. The overlying cliff-forming Dakota sandstone is the most resistant formation in the Grants District and characteristically erodes into dissected mesas as much as five miles wide. The principle uranium ore-bearing horizons are found in the underlying Morrison formation, and the Todilto limestone of the San Rafael group. The Morrison weathers into. a series of steep slopes and precipitous cliffs near the lower part of the Dakota-capped rims, while in contrast, the relatively resistant underlying. Todilto [ ] limestone forms broad benches extending out from the base of these Dakota rims as much as five miles wide. The Todilto benches are covered with overburden to an average depth of about 5 ft in the first thousand ft away from the Dakota rim, but increases to about 200 ft at the base of the rim. In many places however, a thick mantle of upper Cretaceous sediments and Tertiary volcanics "obscures the ore-bearing Jurassic, and precludes exploration. . The known uranium deposits of the Grants District are distributed throughout a zone 85 miles long and about 10 miles wide. Stratigraphy Rocks from pre-Cambrian through Tertiary are exposed in the uplifted areas, but uranium appears to be restricted chiefly to two zones in Jurassic sediments. The Jurassic sediments of the Colorado Plateau have been subdivided into three units, in ascending order: (1) Glen Canyon group, (2) San Rafael group, (3) Morrison formation. The Todilto limestone zone within the San Rafael group has produced the bulk of ore to date, but the promise of the Morrison zone is rapidly increasing. The Todilto formation extends about 300 miles east-west and about 100 miles in a north-south direction. It is composed of a lower, extensive, limestone member and a central, more restricted, thick, pure gypsum member. The Todilto is believed to be of lacustrine origin. The Morrison formation in this area is subdivided, rather arbitrarily, into three members: Recapture Creek, Westwater Canyon, and Brushy Basin. Ore

Jan 1, 1952

By R. Addison

This is the story of the Carlton Mill. But first-a little geography. For those who do not know where the Carlton Mill is, or, perhaps, have only a vague idea, its location is indicated in Figure 1. The plant is situated on the road between the two old mining towns of Cripple Creek and Victor, 10 the west of Colorado Springs. From Denver, it's about 110 miles by road. The story of the Carlton Mill began with the discovery of gold at Cripple Creek in 1890. This discovery set off a major boom such that, by the turn of the century, there were 450 separate operating mines in the district. Gold production boomed early and declined rather rapidly as indicated by the graph in Figure 2. Significant factors affecting production are shown on the graph-the raising of the gold price in 1934 from $20.67 to $35.00 per ounce and the government executive order L-208 in 1942 requiring the closure of all gold mines.

Jan 1, 1983

The Institute maintains a dual relationship with students: (1) an individual relationship with a Student Associate; and (2) a relationship with local organizations of students, known as Affiliated Student Societies or Student Chapters. 1. The conditions of Student Associateship are set forth in Section 9, Article I, of the Bylaws of the Institute (see page 62 and following pages). During 1934, sundry amendments were made for the purpose of improving the student relationship. Postgraduate students are now eligible; and associateship can be maintained, with the payment of the regular dues of $2 per year, for 18 months following graduation in June. With his regular dues, each Student Associate is entitled to receive during the year his choice of MINING AND METALLURGY, METALS TECHNOLOGY, MINING TECHNOLOGY, PETROLEUM TECHNOLOGY, or two "classes" of Technical

Jan 1, 1942

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 Thomas M. Drown

At the meeting of the Istitote in New York, in February, 1880," I described a process of determining sulphur iu metallic allphides, with especial reference to the determination of pyrites in coal. The procem, as then described, is as follows: A solution of sodium hydrate, of 1.25 specific gravity, is saturated with bromine. If an excess of bromiue is used it must be neutralized by the addition of a little more sodium hydrate. The pulverized mineral or coal is moistened with 25 c.e. of this solution autl heated, then hydrochloric acid is added cautiously to just acid reaction. This operation is repeated with another 25 c.c. of the alkaline solution, and again rendered acid. The mixture should be kept hot. The contents of the beaker or dish are then

Jan 1, 1881

The Fifty-ninth Regular Meeting of the Rocky Mountain Coal Mining Institute convening at the Hotel Colorado in Glenwood Springs, Colorado, was declared in session at 10:30 a.m., by Past President Charles M. "Dock" Schloss, Schloss and Shubart, Inc., Denver, Colorado. Dock introduced Mike Zakotnik, Jr., General Superintendent, The Kemmerer Coal Company, Frontier, Wyoming, President of the Institute. His introduction of President Zakotnik follows: Fellow Members, including our charming and beloved secretary, Gussie Whiteside, and our lovely Mrs. Cerise: It is now the appointed time to convene the Fifty-ninth Regular Meeting of the Rocky Mountain Coal Mining Institute which I now declare in session. At our last meeting we elected Mike Zakotnik, Jr., President, and lie has served the Institute intelligently and industriously since his election.

Jan 1, 1963

By Clarence Linville

FULTON1 says: "Speiss is an artificial arsenide of iron containing smaller amounts of other metals. In constitution it is similar to a matte except that arsenic replaces sulfur." For the purposes of this paper it will be necessary to broaden the definition, and I propose the following: Speiss is an artificial mixture of arsenides, of which arsenide of iron may be taken as a type, but iron may be replaced in part or wholly by other metals (such as copper, nickel, cobalt, lead and zinc) and the arsenic may be replaced in part or wholly by antimony. In addition to antimony and arsenic, speisses often contain sulfur. Speisses usually also contain both silver and gold. Table 1 illustrates the variations that may be encountered. TABLE 1.-Speiss Analyses

Jan 5, 1925

By U. M. Mutnti

In order to meet the stringent market requirements for high purity cobalt, ZCCM commissioned the VIR plant in December 1982. The plant comprises a 4.1 tonne/heat vacuum induction furnace with a rated annual capacity of 2,500 MT of barstock. In the VIR furnace, molten cobalt is held under vacuum at 1600°C resulting in the removal of more volatile impurity elements by distillation. Operations todate have demonstrated that Pb, Zn and Cd have good distillation rates in excess of 95%, leading to cobalt containing 1 ppm or less of the above elements. Removal of other impurities such as Se, Bi is about 65% with the finished product still assaying around 1 ppm of each of these elements. Vacuum refining of cobalt offers an economic route for producing higher grades of cobalt from the type of concentrates and treatment processes available within ZCCM. The consistency of VIR cobalt quality has been confirmed by ZCCM and some of its alloy customers.

Jan 1, 1988

By L. R. Flint, W. L. Freyberger, W. J. Howarth

W. L. Freyberger (Director, Institute of Mineral Research, Michigan Technological University, Houghton, Mich.)-The authors are to be complimented on their theoretical analysis of a column flotation process, and the comment I wish to make is not related to that analysis, but to the use of the word "countercurrent" to describe that process. Strictly speaking, the process the authors have described is countercurrent only in the sense of particle-bubble contact. That is, as solid particles and air bubbles pass through the column, the leanest flotation feed (the tailing) comes in contact with the greatest concentration of mineral-free bubbles. However, air bubbles alone do not comprise the complete extracting phase in a flotation system. A second component of this extracting phase is the collector, which is really the extractant inducing transfer of mat-

Jan 1, 1972

By William C. Howe

This paper describes the technical status of the atmospheric pressure fluidized bed combustion (AFBC) process for utility steam generation. Major areas where AFBC development work is needed are discussed. Various approaches to solving these key issues are identified and the ongoing research and development programs addressing the key development areas are described. Other significant programs pertaining to the development of AFBC for utility steam generation are also discussed and needs for future work identified.

Jan 1, 1978

Jan 1, 1980

By A. C. T. Bigg, A. F. Colombo, A. R. MacPherson

The step-by-step study of the Stronsay ores follows the testwork through the initial determination of Bond Rod and Ball mill work indices, the MacPherson Autogenous work indices and the production of a preliminary flowsheet. These results are then used to design a pilot plant program to test the effectiveness of fully autogenous primary and secondary grinding and to determine the feasibility of controlling feed rate by the use of variable speed mill drive and/or varying the mill load. A final flowsheet is recommended with mill sizes and power requirements.

Jan 1, 1992

To determine the effectiveness of multiple types of fire sensors for early and reliable mine fire detection. Background The National Institute for Occupational Safety and Health (NIOSH) has evaluated the effectiveness of multiple types of fire sensors for early mine fire detection and nuisance signal discrimination. Reliable early fire detection in underground mine can be hindered by false fire alarms produced by carbon monoxide (CO) and smoke particulate emissions from diesel equipment, welding, and metal-burning activities. Another false fire alarm source is the cross-interference of hydrogen (H2) produced by battery-charging operations with a CO sensor's chemical cell. Workers can learn to ignore repetitious "false" alarms associated with these emissions. This jeopardizes their safety in the event of a mine fire.

Sep 1, 2002

By Mullens P

Recent advances in technology have allowed many of the problems of directional control of long diamond drill holes to be overcome. Three case histories are presented, from Cobar, Hilton North and Mount Isa Mine, in which careful hole design and the use of wedges and down-the-hole motors have allowed tight directional control of drilling. Substantial savings in time and cost were achieved in all three cases.

Jan 1, 1990

By William J. Kohan

Milling has traditionally been considered more art than science. In the last 10 years, significant improvements in process equipment have been made and we are finally taking significant steps toward approaching grinding as a science. Two machines have been at the center of this development. These are the roll press and the high efficiency separator. The former can be considered as a new technology or adaptation of existing i.e. roller mill. The latter is clearly an improvement of existing technology. Other machines have been introduced to a lesser degree and later. Among these are the CKP and Horomill. The purpose of this paper is to provide an over- view of the currently available modifications for operating systems and options for new milling circuits with some comments on their application and history.

Jan 1, 1997