Search Documents

INTRODUCTION The first installation of large, commercial, high gradient-high field cannister and matrix magnetic separators for removal of impurities from kaolin was made in 1973 (1). Since then the technology and equipment have been widely adopted for clay processing with about 12 units in commercial use. These new separators have filled a need, caught the imagination of many and become a technology worth fighting for. A fight has occurred, and a resolution on royalties for kaolin processing, at least, has been achieved. LIMITATIONS TO APPLICATIONS OF MAGNETIC SEPARATORS Other than the use of these magnets on kaolin clay, no other application has yet achieved widespread adoption. Dr. Iannicelli blames inertia, and1 would agree that it is a factor. There are other reasons too, and if they are examined, they may isolate problems that R&D can significantly assist in solving. I'd like to break the problems into two areas. Machine limitations - the mineral properties are there but performance is insufficient or uneconomic. Separation limitations - the mineral properties aren’t there, but the magnetic separation would perform well if the properties were there (size is right; concentration is right, etc).

Jan 1, 1979

By S. K. Bradford

For years past I have traveled in quest of promising mining-properties, over almost impassable mountain-trails to remote places in the mining-regions, usually many miles from an assay-o5ce. If, upon examination, the fornlation and the ore-deposit appeared favorable, a quick determination of the value of my samples was necessary, in order that I might take intelligent action with reference to the acquisition of the property. A journey with my samples to civilized regions often meant weeks of delay, and perhaps loss of opportunity. How many, under similar circumstances, have returned with their assay-results from such a journey, only to find that some audacious speculator had optioned" the property! True, a first payment could have been made and the chances taken on the results; but experience has taught that rich-looking ore is not of necessity valuable. Personally, I would not hazard a ten-dollar bill on any property without first determining by assay the value of the ore. To carry the usual complete assay-paraphernalia over such mountain-trails was impracticable by reason of the loss of time involved, the great expense of transportation (charged -

Jan 1, 1911

By James N. Gundersen

Geological Engineering can be all-encompassing and it necessarily overlaps many applications of economic and applied geology. Other review articles will cover specific developments in rock mechanics, open-pit and underground mining, geology, geochemistry, geophysics and geohydrology- all of which overlap many fields of economic and applied geology. Nevertheless, there still remains a diversity of new and innovative applications of geology to engineering works through the activities of federal and state agencies, college and university departments, and industrial or consultant firms-particularly with respect to the properties of earth materials and their behavior "as-is" in nature or under the stress of engineering works. Governmental Agencies: Federal John T. McGill (Chief: Engineering Geology Branch; USGS, Denver) relates that recently the Engineering Geology Branch, together with several other branches of the Office of Environmental Geology, has undertaken the production of interpretive maps of unusual character. These maps are commonly called special-purpose or single concept maps. A folio, or series of maps, is prepared for each topographic quadrangle or area selected for study. The individual maps in a given series are printed on standard-size sheets so that they can be bound together if desired.

Jan 3, 1974

By John C. Ludlum

A most stimulating event in the development of world mineral production and technology, the Eighth Commonwealth Mining and Metallurgical Congress was convened at Melbourne Town Hall on March 1 by Sir Maurice Mawby, President of the Congress. Continuing successively at Melbourne, Canberra, Sydney, and Surfers Paradise in Australia and then at Wellington, New Zealand, the four plenary sessions, 50 technical sessions, and both local and extended mine and plant tours during the seven weeks of the Congress, provided a superb medium for assessing the present and looking into the future. There were more than 2300 participants from 32 countries in the various functions of the Congress, including 500 delegates and wives from countries other than Australia and New Zealand, and from 18 countries not members of the British Commonwealth of Nations. Registrants from South Africa numbered close to 200 and there were about 100 from Canada, 70 from the United Kingdom, 60 from the United States, and 20 from Zambia. Although most of the overseas delegates held administrative positions with companies, government agencies, and colleges or universities, professions identifiable from registrations included 100 engineers, 60 geologists and 30 metallurgists.

Jan 8, 1965

By J. D. MacKenzie

THE world production of copper for the first eight months of 1927 shows an increase of 3 per cent over the same period in 1926. Since February of this year, however, production has been considerably curtailed. The United States reduction in the last four months has been offset by the increased South Ameri-can and Belgian Congo production. The United States is now producing 58 per cent of the world production, Chile and Peru 17.3 per cent, Belgian Congo 5 per cent. In 1926 the United States produced 54 per cent, Chile and Peru 16.3 per cent, Belgian Congo 6.3 per cent. Production, Tons 1917-largest war year 1,580,000 1925 1,581,000 1926-increase 3 per cent 1,628,000 1927-increase 3 per cent 1,670,000 Copper Producing Countries, 8 mo., 1927: Tons Per Cent United States 644,000 58.0 Chile and Peru 192,000 17.3 Europe 90,000 8.1 Belgian Congo 56,000 5.0 Japan 46,000 4.1 Mexico 30,000 2.7 Canada 23,000 2.1 Figures are not available for Spain and Portugal, which would probably precede Mexico.

Jan 12, 1927

By Leo Greenberg

As one of its functions, the U.S. Bureau of Mines gathers and analyzes mine accident data, and then publishes annual reports on work injury experience in the various segments of the minerals industry- coal, nonmetals, rock. These reports contain a wealth of detailed data, with a multitude of analyses and cross-tabulations, all intended to shed as much light as possible on accidents and to suggest possible ways of reducing them. In this article, the terms, "injury" and "accident" will at times be used interchangeably to denote accidents which cause disabling injury. The Bureau bases many of its analyses on American National Standard Z16.1 for recording and measuring work injury data. This document establishes two models for measuring disabling injury experience: (1) the frequency rate, obtained by dividing the number of man hours into the number of injuries multiplied by 1 million, and (2) the severity rate, similarly constructed, with the variable of interest being the number of days lost due to these injuries. Similar computations are performed by the U.S. Bureau of Labor Statistics and the National Safety Council. Additionally, these models are used in many other countries, sometimes with minor changes.

Jan 1, 1971

By Robert L. Russell, Henry W. Zimmerman

The Bunker Hill mine in the Coeur d'Alene mining district at Kellogg, Idaho, has been a major producer of Pb-Ag-Zn ores since its discovery in 1887. The mine has produced over 29 million tons of ore from some 20 to 25 veins and ore zones and now covers an area approximately 1 mi long by 0.5 mi wide. The active section of the mine extends from 2500 ft above sea level to 1600 ft below sea level. Ore production is presently at the rate of about 1700 tpd. A 2-mi adit, the Kellogg tunnel, at the 2500 elevation provides access to the main shaft area. Ore is hoisted to the adit level through a 5000-ft. 50º-inclined shaft extending to the lowermost haulage level 1200 ft below sea level. Primary shaft service for men and materials is supplied by three major internal inclined shafts equipped with double-drum hoists. Present production requires ten levels to serve for main line track haulage. These range up to 5000 ft in length and are either 200 or 400 vertical ft apart. Also, many intermediate levels exist throughout the mine.

Jan 1, 1971

By Robert M. Abrams

The passage of an ore pulp through the froth flotation process results in the production, after dewatering, of a finely divided concentrate. This intermediate product must be handled to the subsequent process facilities via beit or other types of conveyors, hoppers, bins, chutes and feeders, and the like. Flotation concentrate has some difficult handling properties such as abrasiveness, sluggishness when moist, or fluidity when dry. These characteristics require the judicious selection or design of handling equipment and the careful engineering of transfer chutes. It is to the special problems which are encountered in this in-plant handling procedure that this paper is addressed. The methods which will be discussed have been developed primarily for the handling of the froth flotation concentrates of copper, lead, and taconite iron ores, but may be generalized, with appropriate modifications, to apply to other similar metallic concentrates. The controlled feeding of concentrates from bins and hoppers is covered along with some of the techniques used to transfer concentrates from one belt conveyor to another. Methods are described for unloading belt conveyors into bins or storage piles. The reclamation from storage piles is also treated.

Jan 1, 1979

By Henry Louis

THE work performed by, the Royal Commission on Mining Subsidence is likely to prove of permanent value, less perhaps for the conclusions it has reached and for the recommendations it has based upon these than for the admirable exposition which it affords of the law concerning mining subsidence and of the legal status of the person who has suffered damage by reason of such subsidence, as also of him whose working has caused the damage. The Commission was appointed by Royal Warrant in the middle of 1925 and delivered its final report in the middle of 1927. The terms of reference to the Commission were as follows: "To consider the operation of the law relating to the support of the surface of the land, and of buildings or works on or under the surface, by underlying or adjacent minerals; to enquire into the extent and gravity of the damage caused by subsidence owing to the extraction of minerals and the incidence of the resulting liability; and to report what steps should be taken, by legislation or otherwise, to remedy, equitably to all persons concerned, any defects or hardships that may be found to arise in existing conditions."

Jan 1, 1929

By J. C. Irvine

Meramec Mining Co., a joint venture by Bethlehem Steel Corp. and St. Joe Minerals Corp., is engaged in the mining, concentrating, and pelletizing of iron ore from the Pea Ridge mine near Sullivan, Mo., about 70 mi southwest of St. Louis. The orebody lies under about 1300 ft of sediments. It is tabular, about 2600 ft long and up to 600 ft thick, and lies in an approximate east-west delineation. The orebody dips about 80"s and is of unknown depth. The ore is primarily high grade magnetite with smaller zones of specular hematite. The Precambrian wall rock is rhyolite porphyry. The mine is serviced through two concrete-lined shafts, 19 ft 1 in. diam and 2500 ft deep. No. 1 shaft, equipped with an "A" type head-frame and conventional cylindrical drums, hoists men, materials, and waste rock; it is also the downcast air shaft. No. 2 shaft utilizes tower-mounted friction hoists to handle the two production skips, each with 24-ton counterweights, and a small man cage. The mine exhaust passes through this shaft. Ore is principally mined by sublevel stoping,

Jan 9, 1972

By G. T. Hahn

On the basis of the recommendation of Lovell, Vogel, and Wernick,&apos; Fry&apos;s reagent*2 was recently c) if decoration of the dislocations by carbon or nitrogen atoms is a factor in the etch pitting. Experiments were performed with samples of a commercial 1020 steel, a vacuum-melted iron (C - 10 to 15 ppm, 0 - 20 to 50 ppm, N < 2 ppm), both annealed 4 hr at 1100°C, and a zone-refined iron (C - 3 to 5 ppm, 0 - 10 ppm, N < 1 ppm ) in the as-cast condition. Saomple surfaces were prepared by grinding to 600A grit and electropolishing. Initially, effects of etching the steel with modifications of the basic Fry composition were examined. It was found that increasing the alcohol or HC1 concentratior~ retarded dislocation pitting; reducing the acid content promoted secondary pitting. Cooling the reagent and the sample did not improve the quality of the etch pits. Best results were obtained with freshly prepared reagent modified by increasing the CuC12 content to 15 g. This composition was used in subsequent experiments. Annealed samples were etched 10 to 15 sec; cold-worked samples —2 to 5 sec.

Jan 1, 1962

By Harrison Schmitt

IN the practice of ore finding the geologist is continually confronted with the question of oreshoot extension, so that the general problem seems worthy of systematic investigation. This problem appears when the reserves are estimated and when the advisability of deepening the shaft comes up. Moreover, there is need for lower development cost to keep pace with cost reductions in other departments, or even to offset a rising cost of ore finding or ore following. This can be gained by close geologic control of the development; and much of the geology involved is that bearing on the downward, upward, and horizontal extensions of shoots. Furthermore, the purchase of a mine or prospect often depends directly on the question of shoot extension; because it is seldom that the ore is fully developed and the purchase price is almost invariably based largely on "possible" and geologically prospective ore. Most current methods for estimating "possible" and the more nebulous classes of ore are crude and indecisive. In the following pages the extension of oreshoots is the major theme, although the more basic subject, the general art of ore finding, is given some space.

Jan 1, 1929

By I. J. Jansen

Introduction The Surface Mining Control and Reclamation Act (PL 95-87) lays a new challenge before the surface mining industry by requiring that prime farmlands must be reclaimed to equivalent or higher levels of yield as nonmined prime farmland in the surrounding area (section 510d). We must now evaluate the situation and plan a mining and reclamation program that will achieve that objective. We must recognize that soil and land needs vary with intended land use and climatic setting. Also, various site conditions determine the potential for constructing a productive soil and the best procedures to accomplish that end. It is necessary to plan the land reconstruction program on a site by site basis in order to achieve the best results. Discussion The Prime Land Concept Terms like prime agricultural land have been used loosely for many years to refer to lands that are highly productive and well suited to agricultural use. The concept of what qualified as prime land varied considerably from one geographic area to another and from one person to another. The term prime farmland, as used in PL 95-87, has recently been defined quite

Jan 1, 1982

By G. K. N. S. Subasinghe

An attempt has been made to explain the behavior of a pinched sluice in terms of the established theories of fluid mechanics and mineral processing. A method has been developed to calculate the underflow discharge by assuming a logarithmic velocity distribution and free gravity fall through the discharge slot. The concentration profile of solids over the depth of flow has been shown to comply with Bagnold&apos;s theory of dispersive shear, rather than turbulent sediment transfer. Even although the results can be explained qualitatively by the Bagnold theory, their complete quantitative analysis will not be possible until more work is done. Consequently, an empirical equation has been developed to predict underflow pulp densities. It has been shown that the process of the segregation of the heavier mineral beneath the lighter can be described by a first order law. From the results obtained, a computer model of the pinched sluice has been developed. This predicts the underflow grade, pulp density and flow rate in terms of the feed and operating conditions. The model can also be used to determine the effect of a change in operating conditions, and for the optimization of rougher, cleaner, and scavenger circuits.

Jan 1, 1984

By R. H. Heinen

Introduction Drilling is the initial operating step In open pit mining. It goes hand-in-hand with the blasting operations to ensure adequately broken material for the excavation equipment employed. The drilling effectiveness is highly dependent on the quality of the drill evaluation. This discussion will center on the parameters that are needed to evaluate drill requirements for a new mine The procedure that is generated can, however, be used to evaluate whether to expand existing operations and replace existing equipment. Methods of breaking ground, other than blasthole drilling and blasting, such as ripping, will not be discussed. The importance of correct drill evaluation extends to the other facets of open pit mining. Inadequate fragmentation, the direct result of poor drilling and blasting techniques, results in oversized, hard digging for the excavating equipment. The result is higher secondary blasting costs, reduced excavation efficiencies, higher excavation costs, higher road repair costs, and higher haulage equipment costs. The main objective of evaluating drill fleet requirements, therefore, is to determine the equipment needed to minimize the operational constraints, caused by blasthole drilling, on other facets of open pit mining at the lowest cash flow costs.

Jan 1, 1979

By Bailey Willis, George Otis Smith

I. Summary of General Features. Location.—The Clealum iron-ore deposits occur on Clealum river, a tributary of the Yakima river; in the eastern spurs of the Cascade range, Washington.† Mount Stuart, 9470 feet in altitude, is a dominant peak of the district, which will therefore be referred to as the Mount Stuart district. By way of the valley and cañon of the Clealum, the ores are 18 miles from Roslyn, the colliery-town, which is reached by a short branch from the Northern Pacific Railroad. Where they occur the valley has an elevation of 2900 to 8000 feet above sea; that of the end of the branch railroad at Ronald is 2345 feet. The grade of the valley from near Ronald to the junction of the Clealum and Salmon Lasac rivers, 144 miles, is 20 feet per mile; thence to the iron-ores it is 130 feet per mile, through a cañon 241/2 miles long. Abreast of the deposits the western wall of the valley is formed by precipices of sandstone; the eastern slope is comparatively gentle, being cut in easily eroded

Jan 1, 1901

By R. E. Sinke

Demerara Bauxite Co. in British Guiana has come a long way in tackling the problem of stripping and removing overburden. When the company started mining in 1917, overburden was hand-loaded into carts pulled by donkeys. Since then it has been recognized that overburden removal is one of the greatest problems. Over the past years a great quantity of equipment has been purchased, discarded as it became obsolete, and replaced with better and cheaper tools. The policy has kept the company&apos;s overburden removal costs within reason. Accurate records of costs per cubic yard and cubic yards per hour per unit have been kept for many kinds of equipment. Walking draglines and hydraulicking equipment are the key approaches to the current operation, but shovels, tractor-drawn wagons, self-propelled rubber tired scrapers, and tractor-scrapers still have limited applications. Mackenzie, operational headquarters of the Demerara Bauxite Co. Ltd., is on the Demerara River, 65 miles from Georgetown, British Guiana. Ore treatment and ship loading facilities are at Mackenzie, head of navigation for ocean-going vessels and the mines are located 7 to 40 miles farther upstream.

Jan 4, 1955

By Luis Emylnn Salas

If the ordinary wet method be attempted for silver-bullion containing tin, much trouble is experienced, varying with the amount of tin present. Even with a percentage as low as 0.05, the end-point is masked by a persistent turbidity, while with amounts ranging from 0.5 per cent. upward, the determination of the exact end-point is impossible, owing to the finely divided or colloidal metastannic acid resisting all efforts to cause it to settle, or to give a clear supernatant liquid. The object of the following experiments was to seek a remedy for these difficulties, and to find the conditions whereby the Gay Lussac method might be applied directly to these bullions. Material containing tin is met with frequently in bullion from Mexico or Bolivia; and tin is carried (sometimes in large quantities) in jewelers&apos; sweeps. 1. A bullion was prepared containing Ag, 74; Cu, 25; and Sn, 1 per cent. A weighed amount was treated by the humid assay-method as if it were an ordinary bullion free from tin. Ten cc. of HNO, (1.21) was added, and the bottle was heated until all traces of

Jan 1, 1913

By Henry Louis

The object of the present paper is to describe a primitive method of gold-extraction, practiced by a small colony of Chinese in the district of Tomoh, one of the Siamese-Malayan States. This district has been worked for gold about 150 years, but has been only twice or thrice visited by Europeans, who are looked upon with a good deal of jealousy by the miners. The gold-district, covering not more than 10 square miles, is situated about Lat. 5&apos; 47l N. and Long. -101&apos; 39 E., on the headwaters of the river Teluban. It is a very mountainous region, lying on the northern flanks of the great range that forms the watershed between the rivers Patani, Kelantan, Teluban, etc., on the north and Perak on the south. The gold occurs in narrow veins and leaders of quartz, intersect- &apos; ing and intercalated among irregularly upheaved and contorted, highly metamorphosed, micaceous and chloritic schists. These veins vary between 3 inches and 3 feet in thickness, and are sometimes very rich. The geology of this region is thus very similar to that characterizing gold-regions all over the world; if must, however, be.

Jan 1, 1892

By Eugene P. Pfleider, Claus Freyberger

Generally, the different methods of financing new mining projects are not well understood by the engineers and supervisory personnel. Nor are the effects of these alternatives on depletion, taxes and profitability readily apparent to even the sophisticated management personnel without the aid of cash flow studies. Fortunately, with the advent of the computer it is possible now to simulate many different combinations of 1) equity, 2) loan and 3) production payment financing with little effort. A general computer program for cash flow analysis of mining ventures has been developed and applied as a case example to a 1967 feasibility study of the Underground Mining of Minnesota Taconite. The effects on profitability as measured both in rates-of-return and present value are presented for various financing combinations. In addition, percentage depletion rates were altered so as to measure the impact of this statuatory allowance. Based on the cost data as presented in the aforementioned 1967 feasibility study, and assuming 7% loans, the rates-of-return vary from 9. 9% to [00] % on equity variations and from 9. 9% to 11.4% on total invested funds.

Jan 1, 1969