Search Documents

By Thomas M. Plouf

Flotation, as we know it today, is a physiochemical method of concentrating finely ground ores. The process involves chemical treatment of an ore pulp to create conditions favorable for the attachment of certain mineral particles to air bubbles which are carried to the surface of the ore pulp for removal. Frother reagents, combined with air and the agitation mechanism, produce the effective bubbles in a flotation cell. A method of analysis is presented to evaluate the effect of frother reductions and additions on a bank of flotation cells, and to economically determine if and to what extent frother reductions and additions are justified. Comparative evaluations of different frother systems, as well as the amount of frother used in a given flotation machine, cannot be made on the frother cost alone. An indepth study must be made to evaluate any given frother as applied to a particular ore body. The recovery of a given mineral is as dependent on the amount of frother as on the type of frother used. An actual case study follows in which the amount of frother required by two different flotation machines was used to make a decision as to which unit performed more efficiently based on costs. This same method may be used to evaluate new frothers as well as to determine if a larger frother addition is advisable.

Jan 11, 1975

By J. B. NEALEY

MANY nonferrous smelting plants have recently adopted natural gas as fuel with resultant economies, both in cost and efficiency of utilization. Not only has this fuel been used for roasting, reduction, sintering, drossing, and smelting, but also for power. All of the three big smelters near Salt Lake City, Utah, have been changed over from coal and oil firing to gas. Among these is the plant of the International Smelting Co., Tooele, an Anaconda subsidiary, smelters of both copper and lead ores. In the roasting division at Tooele are 32 MacDougall six-hearth roasters, each 16 ft. in diameter and 19 ft. high. Two gas burners are installed on each furnace. These burners are of the single-valve, automatic gas-air proportioning type using high-pressure gas at 10 lb.

Jan 1, 1933

By Hans Lundberq

WHEN geophysical methods were first employed in the search for ore deposits and oil accumulations, it was hoped that they would provide a direct means of locating such concentrations. Magnetized needles were used long ago in prospecting for magnetic iron ore, and soon after the discovery of galvanism in about 1790 attempts were made to find concentrations of valuable minerals electrically. Evidence indicating that the early geophyeical instruments were regarded merely as improved divining or dowsing rods is to be seen in the names "mineral finders," "ore finders," etc., that were applied to them. Today, appellations of this kind raise serious doubts in informed minds as to the intelligence and integrity of individuals advocating the use of such euphemistically named methods or instruments, for experience and research have shown that, geophysical, it is never a question of directly locating a given mineral but merely of delimiting its possible occurrence.

Jan 1, 1939

By W. E. Crandall

The No. 4 shaft and hoist at Hecla Mining Co.'s Star mine have been in operation for seven months, and as development of new mining areas proceeds in the lower portions of the mine, the system is being depended upon more extensively for personnel and material handling requirements. The hoist plant is handling full payloads, at rated speeds, over a vertical distance of 5650 ft. One of the special features of this hoist is its precision braking control under all hoisting conditions. Tests indicate that emergency stops can be made with safe deceleration rates and minimum rope and conveyance oscillation.

Jan 1, 1971

By W. J. McConnell

OBSERVATIONS on man exposed to unusual temperatures and humidities, and studies conducted under accurately controlled environmental conditions, have supplied information regarding the physiological responses of the human body which may occur incident to such exposure. These investigations also indicate the relative importance of temperature, humidity and air motion-the three physical air factors that affect human comfort. Many and diverse were the conclusions of early investigators who associated the discomfort observed in crowded and ill-ventilated spaces with changes in the chemical constituents of the air resulting from presumably poisonous exhalations from the body. These are of interest today only because, as a recent editorial in the British Medical Journal1 states, there is still an inclination to believe in the old view that there is some injurious quality of the air in ill-ventilated and crowded rooms, quite apart from dust, microbic infection and heat stagnation. There is a tendency to fly to some mysterious unknown agent such as "deionization," which even certain American engineers are now discussing. This editorial denies the existence of the least proof of any subtle poison being exhaled by human beings or of the ionization of the air having any influence in making open-window ventilation better and more stimulating than mechanical methods which propel heated and conditioned air through ducts. Until proof is forthcoming that certain changes, with which we are not now familiar, occur in the transmission of air from the exterior to the interior of enclosures, the responsible known factors which initiate the physiological responses in human beings are limited to the combined conditions of temperature, humidity and velocity of the air. While some mention was made as far back as 1880 that high temperatures and humidities were undesirable, Hermans,2 of Amsterdam, is credited with suggesting in 1883 that the harmful effects noted in ill-ventilated rooms were due to the fact that the increased temperature and moisture of the air prevented the body from maintaining a proper thermal balance.

Jan 1, 1930

IN order not to deviate from the proposed order both in speaking of melts and of things necessary for guns, I shall tell you at present the method by which iron balls are made. This is surely a very fine invention and a horrible one because of its very powerful effect. It is a new thing in warfare,* because (as far as I know) iron balls shot from guns were never seen in, Italy before those that King Charles of France brought here for the conquest of the Kingdom of Naples against King Ferrandino in the year 1495. Now, although I spoke to you briefly of these when I told you above of the purification of iron, it seems to me necessary to show you again in more detail here how they are made. Therefore I tell you that in addition to iron, bellows, blast furnace, and charcoal, it is necessary to have the moulds, without which they could not be cast. At first, when this work was begun in Italy, it was customary to make these moulds of bronze so as not to be obliged always to be making them of clay. Now the present masters cast the moulds of the same iron in order to save expense. Although I am aware that you should already know how to make these from the methods of moulding taught you before, still I shall tell you the method that is followed in making these, because in the practice of every particular thing there is some divergence from the general procedure. For these balls, first make a ball of wood or of clay, or have one made of lead or iron, round and of exactly the dimensions that you wish. This is if you wish to make only one in your mould; otherwise take as many as you wish it to contain. Bury half of this, or these, in a board or in clay and, having greased them with oil or lard, make a mould over them of plaster of Paris, or of clay if you have no plaster, exactly as you wish it to be in iron or bronze. Then make the other half opposite this. After having taken out the balls make little openings for the gates and vents and like- wise four holes for pegging the parts together. At the back make a stud or

Jan 1, 1942

By Gordon R. Haworth, J. Terry Aimone

The capital-short mining industry, faced with weak metal markets, will need to devise new and novel methods to finance future expansions.

Jan 9, 1977

There is a basic need for the health and safety manager to know what work he or she is to do and how to do it in a more professional way. Peter F. Drucker in The Practice of Management said, "The ignorance of the function of management, of its work, of its standards and its responsibilities is one of the most serious weaknesses of an industrial society-and it is almost universal." The biggest need in mining today is for its managers to have a thorough understanding of the management control activity.

Jan 11, 1979

By Barbara L. Lakin, Sherman K. Okun

According to a recent market survey, the quality and ability of key personnel, plus past performance on the job, rank high as criteria used by mining companies when selecting a project engineering contractor.

Jan 9, 1977

By JOHN A. MALONEY

AS noted in the February issue of MINING AND METALLURGY, an advisory committee to the Museum of Science and Industry of Chicago was authorized by the Institute's Board of Directors, with W. R. Wright of Chicago, former Director of the Institute, as chairman. Since that time the committee has been undergoing organization, and held its initial meeting at the Museum offices in Chicago on April 11 and 12. Functioning as consultants to the Geology and Mineral Industries branch of this new institution, the advisory committee is aiding in building an exhibit which will tell the story of geology, mining, and metallurgy to millions of visitors a year. Although patterned to some extent

Jan 1, 1932

By Andrew B. Crichton

THE oft repeated statements of the United States Geological Survey and the Bureau of Mines that the coal reserves in the United States are sufficient for 3000 yr have given us all a sense of security hard to disturb. If we discount that statement 66 pct, which to the uninformed seems drastic, we would still have 1000 yr supply, and why should mortal man worry about the difference between 1000 and 3000 yr supply of coal. That is exactly the attitude which many who should be better in- formed have taken toward the problem. A recent brochure "How Strong is America," by the New York Herald Tribune, states there is "no end to coal * * The truth is staggering * * U. S. has enough coal to last 4000 years." What the statement actually means is that the calculator got as high as 4000 yr and decided it was pointless to go on. The President's ERP Committee on Natural Resources and others in high places continue to assure the country of our superabundance of coal. In the past few days the “Wall Street Journal" carried an item from Director Boyd of the Bureau of Mines saying that within a hundred years we would need to triple our annual coal production of 6oo,ooo,ooo tons, making it 1,800,000,000 tons annually, and at that rate we had coal reserves sufficient for 1000 yr. In my humble opinion, we cannot now or ever produce 1,800,000,000 tons annually, be- cause we do not have the reserves in the producing districts to do it. Past reckoning in geology may be, as in the Psalms, a thousand years are as yesterday, but the future must be considered more realistically, and "a thousand years" is really a "heck" of a long time. In most developed areas, mining engineers can count the coal reserves in terms of a hundred years or less, and in some important areas now producing large annual tonnages in much under fifty years. They think when they hear of thousands of years coal reserves, reference is made to distant fields and "the fields are always green far away." The estimates of our coal reserves upon which we are relying were made in 1907 under the direction of Marius R. Campbell, Director of the United States Geological Survey. It is apparent this work was not well done. It was necessarily based on rather meager data because of the little development and prospecting as of that date. There were mistakes in the correlation of seams, and they assumed the continuity of thick seams throughout large coal bearing areas where coal often did not exist. The overstatement of coal bearing areas in the Campbell figures are common. The 1907 survey includes all coals over 14 in. in thickness to a depth of 3000 ft. The total coal reserves according to Campbell were 3157.2 billion tons. The production and mining losses that year would amount to -570 million tons and

Jan 1, 1948

Why should I pay $8.50 an hour for dealer repairs when my own mechanics work for $3.50?" The numbers vary, but that's the argument most contractors use to justify doing their own repairs. They don't realize it, but they're probably losing big money. For instance, it takes nearly a quarter of a million dollars in tools alone to equip a shop comparable to an average equipment dealer's facilities. A contractor must buy a lot of expensive, specialized tools he seldom uses, or else settle for the inefficiency of having repairs done by his mechanics with relatively unsophisticated tools. His building soaks up money in rent, maintenance insurance, taxes. His mechanics demand good wages. It even costs money when mechanics aren't repairing equipment. Mechanics get full wages for slack periods and cleanup time, too. This doesn't count as service manhours, but it's still part of the total repair cost. To help contractors uncover these hidden expenses and find out the true cost of owning a shop, some equipment dealers have devised a do-it-yourself "shop cost analysis form."

Jan 1, 1970

By N. G. Johnson

ALL of us are only too familiar with the fact that first the defense program, and finally the war, required vastly increased production from existing sources, and the discovery and development of new sources of minerals and metals. For this vast program, the explosives industry was well prepared. I use the term "well prepared" to cover all the phases of explosives service, which include formulation, design, manufacture, distribution, and application.

Jan 1, 1944

By Carl E. Reistle

ENGINEERS as a group are often criticized because they have been responsible for the development of many technical improvements only to allow the administration of them to pass into the hands of others who may have little understanding of how they operate and little competence in their use. These criticisms are not always justified. There are many engineers who have shown themselves to be great administrators in addition to being great creators or builders, and more and more one sees the engineer demonstrating unusual administrative ability as he moves into the executive ranks. The last five or ten years have seen a new movement developing in this country-a movement brought about through the recognition by business statesmen that successful business administrators and executives just cannot be expected to develop like Topsy, that the management of a company must deliberately take steps to cultivate the proper climate or environment for growth if it wishes to provide an adequate and capable succession of executives in the future. This movement has taken on a number of names-Management Development, Executive Development, Personnel Development-but are these not actually misnomers? Can we develop anybody? In the strictest sense of the word, the author doubts that anyone can change any other person, at least, not much. The change must come from within. Perhaps this movement should be looked at not as a program of developing people but as one of giving people an opportunity to develop themselves. In the Humble Oil & Refining Co. there is an Executive Development Program; maybe it might better be called a Program of Development for Executives.

Jan 8, 1954

By JOHN R. SUMAN

I WOULD like to spend a few minutes describing to you the present condition which exists in the oil industry and then point out some aspects of this deplorable situation in which I think petroleum engineers can be helpful. As you know, the oil business at this time is in a very critical condition, .due to the tremendous potential production in excess of current demand. This is a world-wide condition as well as a national problem, as it is estimated that the surplus production available for the market in foreign countries is of about the same proportion as that existing in the United States. Due to the inability within the United States to hold production within the bounds of demand prices have been slumping for the last four years and at this time have reached the point where the sales value of the average barrel of crude oil in the United States, is far below the cost, of production. In addition to the large amount of potential production available for the market in excess of demand we have in storage in the United States about six hundred fifty millions of barrels 'of oil. Unless something can be done to limit the amount of oil coming onto the market to a point well below the demand, which point will permit the reduction of stocks, it looks as though the 'oil business is facing demoralization.

Jan 1, 1931

By John Lohrenz

Consider an investor who, knowing future costs and revenues, can choose how rapidly to produce from a given mineral source. If the investor elects to make that choice to maximize present value of future profits, how do policies affect the choice? Various alternative policies are examined. Some, such as higher royalty rates, lead to slower production rates than would otherwise obtain. Clearly, the chosen rates of production are policy-dependent. One is wisely counseled to consider how mineral policies affect the rate of production from given sources when analyzing current and alternative policies.

Jan 1, 1982

By Paul H. Rydlund

Substantial priming was a considered necessity for proper initiation of ammonium nitrate-fuel oil mixes as ANFO began to carve its niche in the mining industry in the latter fifties. Heavy priming accompanied the introduction of prills and oil to many blasting operations, large charges of high explosives were commonly used at the bottom, top and frequent intervals throughout the column. As the quality of ammonium nitrate improved and operators became more experienced, primer costs began to diminish. Increased experimentation continued with reduced primer costs a main objective. Cast primers were introduced and became accepted as an excellent companion for ANFO. Although the trend toward larger diameter boreholes became increasingly popular, emphasis on lower and lower priming costs continued. A primer was simply required to produce any type of initiation within the ANFO column to be considered adequate. Suddenly ANFO priming had digressed from excessive to marginal. Early experimental data from test site and laboratory indicated that ANFO had a tendency to react inefficiently in the initiation region of the column unless substantially primed. This was evidenced by the presence of unstable reaction rates detected with newly developed detonation velocity measuring equipment. These low order or "transient" velocities were believed to originate because of inadequate primer strength or a primer diameter to column diameter mismatch. However, the nature of this experimental work was generally confined to small diameter column charges detonated in iron pipe simulated bore-holes. It was questionable whether the smaller scale laboratory data was applicable to large 12 1/4 and 15-in. boreholes.

Jan 3, 1973

HAVING already shown you the methods of making the moulds for casting and how they are to be prepared so that they may receive the melted metals well, it is now necessary, in order to complete the casting with perfection, that I show you not only the operations and instruments by which metals are softened, but also how metals can be made as liquid and fluid as water so they may easily enter into all the hollows of the moulds that you have made. Of these, besides the fire which is the prime agent, there is a very powerful furnace, which is called a reverberator.* I believe this is chosen not only for convenience but also because it is necessary in large casts. This is made of baked bricks, or of crude ones if desired or of suitable fire-resistant stones. Although all masters have the same objective, each one proceeds to make this kind of furnace according to his own ideas so that it can be said that there are almost as many different shapes of such furnaces as there are masters. This can be seen in the place that contains the metal, which is of such a shape that the force of the fire may operate better. Thus some masters are called good who, seeing no farther than what has been shown them, make them circular like a bread oven. Some others make them oval across the fire en- trance, while others extend them lengthwise. Also, there are some who make a single outlet for the flames, some two, and some three. Some make the entrance for the fire high and narrow and others, wide and low. The same is true of the place where the flames are generated, which is called the firebox. Some put the wood in from the side, some lengthwise in the same direction as the entrance for the flames, and some from above by means of a little hole. Also, one makes the vault low, and another makes it high. And while one puts an entrance for air underneath so that the

Jan 1, 1942

By Donald A. Cumming

Since the first major mine development, the company has continually looked for ways of improving drifting methods. The planned increase in production to 60,000 tpd, and the lack of trained personnel, requires new development methods to maintain this high production rate. In order to finish the drifting on the 2015 and 2075 levels, a total of 59,000 ft is required, or two years at the present rate.

Jan 4, 1972

AVERY great profit is derived from removing the gilding and retrieving gold, without destroying the works of silver or other metal. If this method did not exist, the greater part of the gold that is put on certain works would be lost. Even though you might think to scrape it off patiently with a sharp scraper, if it had been drawn with draw-plates, or if it were at the bottom of objects where the scraper could not enter easily, it would be utterly in vain. Therefore, I find that to do this it is necessary to use one of three methods. The first is when it is found on a thin object. Take a large crucible, fill it with mercury, and heat it on a little furnace. When you see that it begins to boil and simmer, put your work in it and stir it around, shaking and rubbing it well in this, and finally rub it with a scratching tool until you see that the mercury has drunk up and absorbed all the gold. Then, having done this, take the said mercury and pass it through an untanned leather purse, and in the bottom of this you will find all the gold like sand. Put this in the bottom of a crucible or in something else over a charcoal fire and evaporate it. If the objects are of a thicker form the gilding is removed from them in another way, by covering them with powdered sulphur and lighting a fire on them. When you see them burning well with the fire all around, beat them in a clean bowl of wood or something else and collect everything that separates with the sulphur from the work; this will be gold in the form of a leaf wherever it has been touched by the fire. The gold is then extracted from this burned sulphur by purifying it in a cupeling hearth with lead. The third method is to touch the gold that you wish to take off the works with an aqua fortis made from saltpeter, rock alum, vitriol, sal ammoniac, and some verdigris.* This acid dissolves and eats the gold by virtue of its corrosive power. Having thus touched the gold with this acid and having saturated the latter with a quantity of gold, put it in a cucurbit and evaporate it over a little furnace as is done with silver, collecting the acid and the spirits if you wish.

Jan 1, 1942