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By S. L. Tainter

This paper describes the nature of engineering and geologic services for the production stage and a review of pit design factors peculiar to the development period. The Mission pit has passed into the mining phase where development is of secondary importance; however: until the pit reaches its final size, development will be a continuing function occurring simultaneously with mining operations. The deposit occurs in an extensive zone of altered sedimentary rocks which have been fractured by three fault systems, flexed or folded, and intruded by monzonite porphyry. The deposit is a low-grade copper sulfide "porphyry" type orebody within a broad zone of pervasive hydrothermal alteration in sedimentary rocks.

Jan 12, 1965

By William Benzon

Bethlehem Steel's Cambria Division coal cleaning and preparation plant, operated by Bethlehem Mines Corp., is located in Cambria County, Pa., about 2 ½ miles southeast of Ebensburg. Here, above ground, is the most modern coal preparation plant in the world. Below the surface is a new coal mine also referred to as "the most modern that could be built today." The preparation plant has a capacity of 1370 tons of clean coal per hr. It serves three Bethlehem mines, Heisley No. 31, Revloc No. 32, and the new Cambria Slope No. 33.

Jan 12, 1965

By R. L. Tobie, H. W. Seaney

Over the years since 1956 when initial experiments were conducted on underground concreting in an attempt to cope with the ground weight and pressure encountered in the development of a large-scale underground block caving system, the use of monolithic concrete linings has grown to include most of the primary development in the mining area. Although the development cost of concrete linings is higher than either timber or steel-supported openings, the repair and maintenance costs are substantially lower, making concrete the most economical means of ground support. Other ad- vantages are also apparent, in that concrete provides superior fireproofing, better ventilation, and a safer, cleaner working place.

Jan 11, 1965

By Arnold E. Lamm

The author addressed a keynote session for all divisions at last October's SME Fall Meeting in Phoenix, Ariz. Discussing the competition from gas, oil, hydroelectric and atomic energy, he said that the market can only be wrested from them "by endeavoring to lower costs far beyond anything we thought possible a few years ago." He saw the rate of return for the industry as "grossly inadequate." Looking ahead, Mr. Lamm saw only a few extremely large generating plants being built. "Purchase of coal for such plants," he said, "will probably be confined to a single source on long-term contracts. Only those coal companies who are able to locate huge reserves, close to adequate cooling water, capable of being mined and transported at the lowest cost in relation to quality, will be able to compete. . . While the market for coal will be very large in terms of tons, it will be most selective and confined to a few transactions of very great magnitude. "Coal offers a proven and tried method of producing energy. The available strippable reserves of Western coal and mineable underground reserves offer the cheapest source of energy available. History will attest that coal has been a steady and stable source of energy. Up until recently, the energy market of the West has had to depend on natural gas which product has had a long and steady price escalation. Statistics show that, where coal is available, the price of gas is quite stable, but where gas is the only available fuel, it has traditionally followed a steady and upward price trend.

Jan 11, 1965

By Ray W. Ballmer, K. H. Matheson

Since start-up in 1906, Bingham had been a rail pit, beginning with steam locomotives and converting to electric locomotives in 1923. Ore production was maintained by effective utilization of avail- able rail equipment. From time to time, as it became necessary to deepen the pit and as stripping ratios increased, studies of alternative material haulage systems such as diesel locomotives, conveyor belts and trucks were made. Conversion from rail haulage with electric locomotives could not, however, be justified. Because of a gradual decline in ore grade, a program was approved in 1963 to raise ore production to 108,000 tpd. The decision posed a serious problem: due to built-in inflexibility and other limitations, a parallel expansion of the rail haulage system was impractical. (Track and trolley wire relocation causes greater shovel downtime than required for normal maintenance; instability of the dumps and the resulting additional track maintenance increases greatly as the daily volume of waste material increases.) Studies indicated that economically the most favorable course of action would be the replacement of rail haulage on the upper levels of the mine by truck haulage.

Jan 11, 1965

By J. C. Donnell, O&apos

Sinking an inclined ventilation shaft at the Never Sweat mine of The Anaconda Co. has required a unique underground hoisting arrangement because the shaft changes direction from vertical to 71.5º. Access to the project is made through the High Ore shaft to the 2800-ft level, then by crosscut to the bottom of the vertical Never Sweat shaft. The 71.5º incline shaft starts at this point, which makes an unusual operation as the 60-cu ft sinking skip coming up the incline changes into a vertical position above the 2800-ft level before going into the dump scrolls. This requires both rollers and guide shoes on the skip. Coming up the incline to the collar of the shaft the loaded skip enters into a guard before reaching the vertical section. The tendency of the surface- mounted Never Sweat hoist is to lift the front wheels of the skip off the track, so the guard keeps the skip on the rails during the transition.

Jan 11, 1965

By Geoffrey Purcell

For anyone contemplating flotation research with only a very limited amount of mineral available for testing, the choice of suitable experimental equipment is by no means obvious. Hallimond's original and delightfully simple cell1 has been modified by subsequent investigators2to give quantitative and reproducible results on small samples. However, the modifications have necessarily compromised its simplicity, and the services of a skilled glass blower are required to duplicate the cell. Vacuum flotation tests3 at best qualitative and may, under certain conditions4, be quite impracticable. A hundred years ago, Thoreau observed that "our life is frittered away by detail," and his advice was to "simplify, simplify," The success of the simple cell described below, which was developed by the author and differs somewhat from Hallimond's original, suggests that Thoreau's advice still has merit a century later. CELL CONSTRUCTION The cell [Fig. 1 (a) and 1 (b)] consists essentially of a 25-ml pipet from which has been cut the con- stricted top. The length cut off is not critical since this merely determines the final volume of the cell. Cell volume may be varied in this way from 20 to 50 cc. A pyrex extension tube, equal in diameter and approximately half the length of the cut pipet, is attached to the top of the pipet by means of 2 ½ in. of close-fitting tygon tubing. When assembled, the two pyrex tubes should be spaced about ½ in. apart. Another length of tygon tubing is added to the extension piece for sealing purposes. A ¾ -in. disc of porous material (teflon cloth is ideal), secured in place over the pipet tip with another piece of shaped tygon tubing, completes the cell assembly. Tygon tubing may be shaped by pushing it over the pipet tip or some similar form and heating carefully over a low flame. For flotation [Fig. 1 (c) 1, the pyrex extension tube is rotated approximately 70º from the vertical and held in position by a wire hook and eye. Floated material, after reaching the free surface, falls and rests on this inclined plane. The barrier formed by the bent tygon tubing ensures that floated material does not slide back and return to the vertical portion of the cell.

Jan 11, 1965

By George W. Lower, Robert B. Booth

The use of cyanides in the extraction of gold and silver is well known1 Such extractions employ concentrations of cyanide in the range of 0.02-0.25% sodium cyanide equivalent in leaching cycles of 24-48 hr and frequently longer. Copper minerals, even though minor components of precious metal ores, dissolve in these cyanide leaching solutions, consume cyanide, cause fouling of mill solutions, and thus interfere with the precipitation and recovery of gold.2,3,4 This paper presents a summary of laboratory investigations on the use of cyanide solutions as extractants for copper from various copper-bearing ore fractions. In view of the metal contents involved, it will be apparent that larger quantities of cyanide are required to extract copper than for the extraction of precious metals. In cyanide solutions of concentrations generally favorable to copper extraction, sulfide and oxide copper minerals were found to dissolve rapidly at room temperature and atmospheric pressure.

Jan 11, 1965

By K. P. Wang, Virgil L. Barr

The U.S. Minerals Attaché Program, similar to the scientific and technical attache programs of other industrialized nations, is designed specifically to keep surveillance on significant worldwide developments in minerals, metals, and fuels. Knowledge of international minerals developments is essential for both domestic planning and conduct of foreign affairs. CONTROLLED BY DEPT. OF STATE Ten minerals specialists-eight minerals attaches and two petroleum attachés-man this far-flung, worldwide program for the U.S. Government as best they can. Minerals attach& also handle oil, in posts lacking petroleum attaché. The legislative authority for the Minerals Attaché Program is the Foreign Service Act of 1946 and succeeding amendments and Presidential Executive Orders. Therefore, this program is controlled by the Department of State. Interior (representing the Bureau of Mines) and State collaborate in policy formation and direction by means of a "memorandum of agreement" which covers establishment of posts, selection of officers, contents of reports, and supplemental training. State also has about half a dozen nonspecialist officers to complement the work of the minerals and petroleum attaché. It is not the intention here to evaluate the administrative arrangements of this program but rather to describe it and to provide examples of the important job it is doing.

Jan 11, 1965

By H. M. Conger

Kaiser Steel Corporation's Eagle Mountain mine is located in the Colorado Desert, 60 miles east of Indio, California. Iron concentrates from the mine are shipped by rail 164 miles to the' Company's steel mill at Fontana, and also to Longbeach, California for export. Temperatures are typical of the lower desert ranging from a high of 120 degrees in the summer to a low of 25 degrees in the winter. The average, annual rainfall of about two inches comes mainly as cloudbursts during the summer months. From its inception, the Eagle Mountain mine has had the problem: of breaking its mine rock. Practices followed from 1949 until 1962 were very costly, did not produce uniformly good fragmentation, and were incapable of sustaining, high production. During this period, every conventional type of explosive was tried and found to be unsatisfactory for one reason or another.

Jan 11, 1965

By John V. Beall

When the mineral seekers came, they brought romance, excitement and, too often, transitory riches. It has been so for uncounted centuries. While the rich ore lasted, living was high and money flowed-mostly out of town. The whole creation was like a circus. The headframe went up like the center pole of the big top. The reduction works was an ingenious affair; an opportunity for self-expression by the mining engineer on the job. When the high grade gave out or the bottom dropped out of the market, the whole show folded. Machinery was scavenged for the next location. About all that was left were the raw footings, like giantsteps on the hillside; and the headframe above the silent diggings. Mostly, the people went away too. Arizona Territory was like that at the turn of the century. It can still happen. But, in copper, the age-old pattern has been disrupted. From Mineral Park in the northwest to Chino in the east and Cananea in the South, a growing number of companies have emerged-large, stable, productive. Southwest copper is truly a mighty industry, accounting for one fifth of world new copper production. In this period of scientific development, changes are fast, often dramatic. But even mining engineers, or possibly more so because they have an intimate knowledge of the industry, fail to appreciate the evolutionary changes that have shaped Southwest copper into what it is today.

Jan 10, 1965

By Paul C. Merritt

The story now unfolding on the Mesabi Range is more than just another chapter in the continuing history of iron mining. It is an epic of foresight, research and pioneering instinct just now culminating in the rapid growth of a new industry hardly more than ten years old. And that growth has been impressive. In the decade that has passed since Reserve Mining Co. blazed a trail as the first successful large- scale commercial taconite operation, the number of plants now existing or soon to be operating has grown to six. From Reserve's initial capacity of 3 million tons of pellets per year, total production capacity on the Range has surged to 31.5 million tons while capital investment has leaped from $300 million in 1955 to almost $1 billion today. During the past year alone, more than $500 million has been committed to these projects, an amount probably greater than that going into any other single mining area in the world. There is more yet to come.

Jan 10, 1965

By A. Bauer, P. Calder, N. H. Carr, G. R. Harris

Smallwood mine is part of the Iron Ore Company of Canada's Carol Lake operation and is situated in Labrador, 240 miles north of Sept-Iles, Quebec. Last year, 15 million tons of crude ore were crushed to yield 6.3 million tons of concentrate and pellets. This year the figures will be 17 million of crude and 7 ¼ million tons of concentrate and pellets, which is the full plant capacity. Carol Lake ores consist primarily of specularite and magnetite mixed with quartz. Since both rotary and jet piercing drills are used, it is often desirable in planning to know in which regions of the orebody, or new orebodies, a particular drill will be most economic. This makes it necessary to establish a correlation between drillability and pierceability and some physical rock property. For the rotary drills a good correlation was found with penetration rate and grinding factor index. The jet piercers were found to have a reciprocal relationship in the sense that the best rotary ground was the worst jet ground and vice versa. It is also indicated how an economic comparison could be made using these penetration rate versus grinding factor index curves, the hole size distribution curves for single pass and chambered holes, and the mine distribution curve for grinding factor index.

Jan 9, 1965

Merritt: Karl, you are a native New Englander, having been born in St. Albans, Vermont, in 1885. How did you decide on becoming a mining engineer? Twitchell: While I was attending St. Albans High School, my uncle, who had been the American Consul in Kingston, Ontario, for many years, told me of the excellent mining school there. He also introduced me to a Canadian mining engineer who sparked my interest in mining by noting the possibility of achieving personal success without always being under salary. Well, that appealed to me, so I applied to the Kingston School of Mines at Queen's University.

Jan 9, 1965

By J. Hall Carpenter, James E. Lawver

Shortly after the passage of the Taconite Amendment in Minnesota, several mining companies announced their intention to build new magnetite taconite plants and another announced its intention to augment present facilities. It is clear that Minnesota will enjoy an expanding magnetite taconite industry, but despite the fact that the reserves are large, eventually they will have to be supplemented by oxidized deposits. Furthermore, not all producers have magnetite taconite reserves. Due to the extensive oxidation of most of the western part of the Mesabi Range, there are no large blocks of unaltered magnetite taconite that lend themselves to open pit operations. Unless a commercial process can be developed to concentrate the oxidized, or so- called "nonmagnetic", taconite and semi-taconite, the existing mines operating in the western part of the range will be forced to shut down when the direct shipping, wash and gravity ores are depleted, or are no longer salable, because of their poor quality compared to high-grade pellets. KNOWN PROCESSES COSTLY The enormous reserves of the oxidized iron- bearing formation have offered a tantalizing challenge to metallurgists for many years. In fact, several processes for concentrating certain types of oxidized ore have been successful at both laboratory and pilot plant level, but to date no process for concentrating semitaconite or oxidized taconite has reached commercial fruition. Magnetic roasting, followed by low-intensity magnetic separation1, has shown considerable promise because the high iron recovery makes the ratio of concentration of many of the oxidized ores more favorable than that of magnetite taconite. However, the capital and operating costs are high and, in many cases, a high- grade concentrate cannot be made without resorting to flotation of the magnetic concentrate. Hence, most research groups are investigating alternate methods of concentration with the hopes of reducing the cost.

Jan 9, 1965

By Thomas S. Lovering

Hot springs, geysers, steam-emanating fumaroles- these creatures of nature were until recently little more than geological curiosities, but today they are exciting the interest of engineers around the world for it has been shown that such hyperthermal areas can be profitably harnessed by man to provide heat and power for his communities. Although water from hot springs was used centuries ago to heat some Korean dwellings, is being used today by one-third of Iceland's population for similar purposes, and is finding industrial applications in New Zealand and elsewhere, the most dramatic use of geothermal energy has been its conversion into electricity. The largest installation at the present time is that at Larderello, Italy, where the Count of Larderello began to experiment in the production of electricity from geothermal steam in 1904. Eight years later after a quarrel with the local power company, the Count installed his first steam turbine, a unit of 250 kw capacity.

Jan 9, 1965

By Benj. Lazer

Multiple seam mining has been studied and writ- ten about extensively in the past and in the latest review of the subject in 1956 David Stemple covered it exhaustively. The present discussion has to do with only one phase of the problem-"The effects on upper seams when the lower seams have been mined first." The study presented here is based on observations made in mining operations in southern West Virginia and adjoining areas of Virginia and Kentucky during the past 43 years. These observations are largely confined to the Pocahontas coalfields of southern West Virginia which have, since 1883, produced well over one billion tons of coal from an area of about 300 sq miles and where multiple seam mining has been active, or is now active, at more than 40 operations. The observations and conclusions as to the effects on upper seams when lower seams have previously been mined are therefore related only to the local coalfields in the area of the three states named but I believe that they can be applied generally to other coalfields.

Jan 9, 1965

By S. C. Fall

The basic aims of the drilling and blasting program at the Mission mine are fourfold: 1. To provide 100,000+ tpd of broken alluvium and rock material for shovel excavation; 2. To obtain fragmentation that will permit the most efficient digging of the broken material and provide an acceptable crusher feed; 3. To conduct the drilling and blasting program in accordance with approved safety procedures; 4. To obtain these objectives at the lowest possible cost. The material that is mined from the pit is divided into four different rock types and the overlying alluvium. Each of these materials is broken by using procedures tailored to its individual characteristics.

Jan 9, 1965

By J. J. Marcus

Mineral industry decision-makers are frequently required to select between competing equipment. Various criteria and methods are currently being used, and this writer would like to suggest a method recently tested on two large power shovels in an open pit mine. An initial examination of both shovel A and shovel B indicated that the latter should give the best overall results. since: 1) It swings 13% faster; 2) it carries a dipper with 23%: greater capacity; 3) purchase price is 8.6% lower; 4) shovel weight is 12.5% greater; 5) it has considerably greater bail pull under most operating conditions; 6) the electric controls are of a more modern design. However, shovel B has half the service life. With these points in mind, shovel A was selected by The Buckingham Method, an operations research technique.

Jan 9, 1965

By K. L. Sehgal

Minerals are the basis of modern civilization: their exploitation and effective utilization are a yard- stick for measuring the comparative prosperity of different nations. This is particularly true in India where industrialization is just beginning to pick up speed. Production targets for our Fourth Five Year Plan (1966-71) are far ahead of the figures for, say, 1950 (the year we won independence) and show the extent of the expansion. Many problems remain to be solved, not least of which is the shortage of raw materials. India is no novice at utilizing minerals. Archaeological ruins at Harappa and at other historical places in the country show evidence of the fact that the ancient Indians not only knew the art of winning minerals from the ground over 6000 years ago-they were also well acquainted with metallurgy. Some of the present sites of mineral exploitation are the same as those our ancestors worked for many centuries.

Jan 9, 1965