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By G. M. Carr-Harris

"THE SUBJECT of permanent molding has received a great deal of attention in the technical press as illustrated by the many excellent articles in the bibliography which follows. In general, this covers the period 1940-1958 and is merely representative of what is available. Numbers in •brackets refer to items in the bibliography.It may be desirable at the outset to give a few definitions covering those terms directly related to this subject. The following is a definition of permanent-mold casting as given by J. W. Meier in a paper, ""The Non-Ferrous Metals and Alloys"", read before the Ottawa Valley Chapt.er of the American Society for Metals:""Permanent Mold Casting is used where a large number of castings of the same part are required and higher mechanical properties, greater density and closer tolerances are essential. Since metallic mold s are very expensive, the number of castings must be sufficient to, defray, at least partially, the added expense. Molds are usually made from a good quality cast iron, 1but other mold materials, such as the aluminum and copper alloys, graphite, ceramics, etc., are being used in certain cases. Important factors in permanent mold casting are the mold temperature; the proper mold dressing; and, as in all other casting methods, the mold geometry, that is to say, the design of spruces, gates, risers and vents""."

Jan 1, 1960

Many of the difficulties faced by the U.S. mineral industry in 1982 and 1983 emanated from the worldwide recession, from the high value of the U.S. exchange rate, and, in part, from actions taken by foreign governments to protect selected industries. While some problems will be minimized with continued worldwide economic recovery, others remain and may require special attention by U.S. policymakers. These problems include declining U.S. production capacity in selected mining and mineral processing industries, the impact of the high value of the U.S. exchange rate, and protectionist trade practices by competitor nations. Illustrative of the last is the International Trade Commission (ITC) determination in June 1984 that both the domestic steel and copper industries have been substantially injured by foreign imports. In its July 1984 recommendations to the President, the ITC suggested higher tariffs and quotas for 5 years on 70 percent of steel imports but conditioned the aid on cost-cutting and modernization steps by the domestic industry. In the copper decision, two commissioners recommended increased duties, two recommended that quotas be imposed, and one recommended that no relief be provided. The President decided in September to seek voluntary restraint agreements with nations that export steel to the United States and rejected both quotas and higher tariffs on copper imports. General Economic Setting This decade opened with the U.S. mineral industries struggling to deal with double-digit inflation, record high peacetime interest rates, and almost 7 years of oil-cartel-induced energy price increases that seriously affected the profitability of energy-intensive industries such as mineral production and processing.

Jan 1, 1985

By Herbert Hoover

DURING the year, the' Institute has made the most remarkable growth in its history. Our actual increase in membership was 1816 and therefore was 80 per cent. larger than any previous year. Even without expectation of any abnormal growth, we should pass in the year 1921 the 10;000 mark. The causes of this increased growth are not far to seek.. They lie in the widening vision of the Institute's work, not only in its relation to' the profession but as an avenue of service to the nation as a whole. The Institute is today in the first rank of influence among public institutions in the country. During this year we have, for the first time in many years, had a ?deficit of some $3000 in our finances. The sum is not important, but it- does indicate the tendency of the times, and that is the high cost of living:' The increase in our expenses lay, to the largest degree, on the publishing side of the Institute's work. If we compare the year 1918, as a fairly repre¬sentative year, with that of 1920, we find that the costs of issuing the' Institute's publications, after deducting the income received from these publications, shows a .net increase of about $33,000. for the year. This has been to some degree due to the enlarged membership but to a large degree due to the cost of the paper and printing.

Jan 1, 1921

By Stephen A. Orr

Underground mining is a dynamic art and science with a diverse set of design, production, and economic criteria that must be considered before selecting an optimal method to extract the ore. While all methods can be technically classified as either self-supported, supported, or caving, the multitude of subsystems and existing variations bear witness to the fact that each orebody is unique and, as such, justifies an individual approach to optimize mineral extraction. In this sense, underground mining is an art. The ability to evaluate the unique characteristics of each ore body and utilize sound engineering principles to design the optimal system constitutes effective method selection. The task by no means ends at this juncture, however. Subsequent implementation requires an ability for modification. Very rarely are all the facts available to make a concrete decision prior to development of the resource. As a result, the risk of a wrong decision can never be eliminated. This requires a significant degree of flexibility with each method. Each unit of exploration, development, or exploitation work contributed to a deposit enhances knowledge of the ore body. The best mining methods are those that correctly account for the known parameters but provide an allowance for change at minimal cost and adapt to unanticipated conditions.

Jan 1, 2008

By J. J. Forbes

Problems connected with the incidence, effects, determination, and control of dusts are still much before the public, although more information is available to the layman than when Bulletin 400, of which this publication is a revision,5 was issued in 1937. Bulletin 400 attempted to assemble information in convenient form on various phases of the dust problem, largely in the mining and allied industries. This revision includes data that have accumulated since 1937 and some that appeared previous thereto but were not available to the authors at that time. The literature on this subject is so voluminous that no attempt has been made to include all published material or all types of dust diseases, but only to assemble some of the more outstanding data on several aspects of the subject.

Jan 1, 1950

Wildcat strikes in the Appalachian coal fields, primarily in West Virginia, have resulted in an estimated 4.5 million ton loss in coal production during July and through the first week in August. Since then, the strike intensified further, and on August 9, nearly all of West Virginia's 60,000 miners were off the job with another 10,000 miners on strike in eastern Kentucky. The Bureau of Mines estimates that West Virginia's coal output is currently (8/9) eight million tons below last year when the state produced 108 million tons. West Virginia, the Nation's second largest coal producer of coal behind Kentucky, has not failed to mine over 100 million tons a year since 1938. At the end of the second week in August, nearly all coal miners in West Virginia remained out. The strike is a protest against a cutback in union health and retirement benefits. An announcement June 23 about the United Mine Worker's health and retirement fund precipitated the strike, Fund directors said that because of inflation and production losses caused by earlier wildcat strikes and the severe winter, miners would have to pay the first $250 of hospital costs and 40 percent of doctor bills, up to $500 a year. Previously, the funds paid all hospital and doctor bills. According to the West Virginia Coal Association each day of the strike in West Virginia results in a loss of coal production of 500,000 tons, a loss of $3.8 million in miners wages and $1 million in contributions to the UMWA's health and retirement fund.

Jan 1, 1977

By Hal M. Lewers

IN the past few years and especially since the beginning of World War No. 2, gold has attained a new, important. and critical place in the international scene, and in world affairs. In the past, as far back as history records, most wars have been waged for the purpose of acquiring it from someone else by conquest. But now, the most titanic struggle of all time is being waged with the avowed purpose of not only destroying it, but of destroying all that it stands for and represents. A tradition dating back to ancient Rome, affirms that battles are fought by men with weapons, but wars arc eventually won by gold. The validity of that tradition is now being subjected to its major test. Hitler has proclaimed that in his new world order, the work dollar or reichsmark, a beautifully engraved paper currency representing only a theory of value, based on unit of work and production, will become the supreme medium of world exchange, and that gold eventually will he valueless and obsolete.

Jan 1, 1942

By Courtney A. Young

Cyanide is a fast-acting, highly toxic substance but, at the same time, is deemed essential for sustaining life as well 'as our standard of living. In this manuscript, the facts about cyanide are presented beginning with a brief history and definition and ending with a discussion on cyanide alternatives. Other topics include speciation, physical characteristics, toxicity, manufacturing, cyanogenics, cyanide cycle, separation, destruction, and markets including those outside the mining industry. Emphasis, of course, is placed on gold production by leaching and how it is influenced by ore type, mineral characteristics and economics as well as its advantages and disadvantages.

Jan 1, 1998

By Pat McCarran

WHEN this Government was founded, the framers of the Constitution wrote into that instrument a provision that Congress should "coin money and fix the value thereof;" and the Constitution prohibits making anything but "gold and silver" lawful money. So silver is written into our basic law. Shortly after President Washington took office in 1789 the Congress passed the first Mint Act, setting up the U. S. Mint. In that Act, signed by President Washington on April 2, 1792, the weight of the American dollar was fixed, and it was provided how much silver should be contained in a silver dollar and how much gold should be contained in a gold dollar. It was decided that 371 1/4 grains of pure silver was to be the standard dollar of America. That standard with respect to the pure silver content of the dollar has never changed.

Jan 1, 1947

Discussion of the paper of R. J. COLONY, presented at the New York Meeting, February, 1921, and issued With MINING AND METALLURGY No. 169, January, 1921. R. J. COLONY (author's reply to discussion).-The work of Sosman and Merwin on the system lime-ferric oxide, mentioned by Mr. Rankin, was not overlooked. When studying portland cements and portland-cement clinkers petrographically, however, the lime-iron compound was difficult to correlate with the very definite dicalcium ferrite described by those investigators, which possesses such well-defined optical properties. In portland cements, the calcium ferrite (or ferrate?) is an indefinite, fuzzy, and generally amorphous, or apparently amorphous substance that is distributed interstitially with respect to the other grains, from which it was very difficult to derive any satisfactory results. For this reason, the writer, tentatively, chose to regard it as related to the aluminate, and assigned to it the composition 3CaO.Fe203, which may be incorrect, however, as Mr. Rankin suggests.

Jan 8, 1921

By Warren E. Morrison

The first major evaluation of the nation's raw materials prospects after World War II was completed by the President's Materials Policy Commission (Paley Commission) in 1952 and submitted to the President in June of that year, as a five-volume study entitled Resources for Freedom. The bulk of the report was devoted to an analysis of the past, present, and probable future of the Nation's mineral supply industries. The Commission's evaluation of the future situation regarding minerals was derived from its forecasts of the probable domestic demand for the major minerals in the 1970's. This demand analysis was made in the context of probable worldwide demand. Several crucial assumptions were made by the Commission's fore-casters. It was assumed in 1950 that the next 20 to 30 years would see no major wars and be a period of sustained economic growth. Another assumption was that the anticipated demand for raw materials must be supplied at essentially no increase in real cost in order to avoid crucial supply problems. The Commission's forecasts were derived within the context of the country's expected future rate of economic activity. The gross national product (GNP) growth to 1975 was derived from projections of the number of people in the labor force, hours of work, and an index of probable production measured per unit of labor input. It was believed labor hours would decrease and labor productivity would increase. The result was a forecast GNP growth rate of 3 percent.

Jan 1, 1970

By AIME AIME

TRANSFER to the Bureau of Mines of the responsibility for conservation and production of helium, and announcement that a proposal has been made to the President for commercial operation of the Los Angeles has attracted new attention to the helium program of the Government. The matter is one in which mining engineers, and the mining industry in general, have a peculiar interest. Helium is a byproduct of the petroleum and natural gas industry. It is found in certain of the natural gases which have themselves been discovered, in the main, in the search for oil. If it is to be produced on a large scale, the conservation and development of the fields will necessarily be done by the men of the oil and gas industry. There is no known or expected source of supply of quantities of commercial importance save in the natural gas fields. Not all gas wells supply helium and none of them supply it in important percentages. If it were necessary to prospect a field, develop it, lay pipe lines and build production plants for the helium alone, the cost would be prohibitive. On that basis helium would necessarily be restricted to essential war uses, where cost is subordinate to need. As a byproduct of the natural gas in certain, at least, of the fields in the United States there is distinct reason for anticipating that it may be produced in amounts and at a cost that will permit its regular use in commercial airships.

Jan 1, 1925

Martin Marietta Aluminum, Inc. followed Howmet Aluminum Corp., Revere Copper and Brass, Inc. and Anaconda Co. in lifting August prices of 99.5 percent unalloyed aluminum ingot by 3 cents to 56 cents per pound. Prior to these moves, Kaiser Aluminum and Chemical Corp. raised its June ingot listings by 4 cents to 57 cents and Consolidated Aluminum Corp., 4.5 cents to 57.5 cents. Domestic merchants increased July quotes by slightly more than 1 cent to 51.3-51.8 cents per pound. ARSENIC The Occupational Safety and Health Administration (OSHA) issued new standards, effective August 1, for worker exposure to inorganic arsenic, a toxic substance linked by OSHA to lung and lymphatic cancer. The new standard will limit worker exposure to 10 micrograms per cubic meter of air over an 8-hour period, a drastic reduction from the previous standard of 500 micrograms for a like period. Implementation of the new standards may be the most difficult and costly for copper smelters where arsenic is associated with the copper feed material but problems will also be encountered by producers of arsenic containing products such as for pesticides and herbicides. The new standards allow use of personal protective gear for workers as an interim measure until plant engineering controls can be put into effect.

Jan 1, 1978

U.S. demand for building and construction materials, such as construction aggregate, gypsum, and cement, remained strong in 1989. Cement imports declined slightly, representing about 17% of apparent consumption compared with 19% in 1988. Mexico, supplying 29% of the total, was the primary source of imports, followed by Canada with 21 %, Japan with 14%, and Spain and Greece with 10% each. Mexico was also the target of an antidumping petition, filed by producers in Arizona, Florida, New Mexico, and Texas, alleging that Mexican cement was being sold in these areas at less than fair value. This was the second petition filed against Mexico in the last 3 years. The International Trade Commission made a preliminary determination that the cement industry in these regions was materially injured by Mexican imports. U.S. demand improved for construction aggregate for the fourth consecutive year and was at a near-record level. The U.S. gypsum industry performed well, even though new housing starts decreased for the third consecutive year. Increased U.S. exports of gypsum wallboard and strength in the remodeling markets offset the impact of declining housing starts.

Jan 1, 1990

By H. Foster Bain

I. INTRODUCTION. By H. FOSTER BAIN.+ THE recently aroused public interest in the conservation of our natural resources has peculiar importance to mining-men, since they deal with resources which are stored products. Within certain limits, the fertility of a worn-out soil may be restored, deforested areas can be replanted, one year's wasted water-supply is followed by another; but coal and ores, once taken out, cannot be mined again, and should therefore be conserved with especial care. This means, however, not that mining should be restricted, but that it should be done most economically and with the minimum of waste.

Nov 1, 1908

By J. E. Dutrizac, J. B. O'Reilly

"Zinc is a relatively abundant element which occurs as both high-grade sulphide ores {sphalerite ZnS) and oxide ores which the ancients collectively termed ""calamine"" (smithsonite ZnC03 and/ or hemimorphite Zn4Si201(0H)2 - H20 and/ or hydrozincite Zn5(C03) 2(0H)6). Although oxidic zinc is readily reduced by carbon, the process becomes thermodynamically viable only at - 1000°C, and at this temperature the zinc is released as a vapour (B.P. 907°C). Casual cooling of the vapour results in its re-oxidation by excess combustion air or even the carbon monoxide product of the reduction reaction. ZnO + C = C09,, + Zn vapom Only fairly rapid quenching of the zinc vapour and the isolation of the reduction products from the combustion gases will yield metallic zinc; these conditions were not produced deliberately until the advent of distillation technology. Until quite recently, the principal use of zinc was in brass manufacture; galvanized iron was not discovered until the 19th century and zinc casting alloys are a relatively recent invention. As will be seen, brass could be produced without recourse to a pure zinc intermediary, and the discovery of brass preceded that of zinc by many centuries. The purpose of this paper is to outline the discovery and early development of both zinc and brass with special reference to the European scene."

Jan 1, 1999

By Wendell L. Reich

Percussion drilling dates back to the hand operated star drill and hammer. Eventually steam and compressed air were substituted for muscle power and the mechanical percussion drill was born. From the hand held jack hammers, driving a forged steel bit into the rock, there evolved the jack leg, the rubber tired and crawler mounted drill carrier with automatic feed, increasing power and reducing man?s muscle requirements. Because the reaction of a blow on one end of a piece of steel has to be transmitted to the other end there is a limit to the depth or length of drill steel that can economically be used in out of the hole percussion devices. During the late 1800?s there is evidence that designers were attempting to put the percussion tool at the bottom of the hole, directly on the bit, in order to avoid the long drill steel which absorbed much of the blow, leaving little to be applied to the bit and the rock being drilled.

Jan 1, 1972

By Zay Jeffries

AN acute current shortage of copper, with the prospect that conditions may become worse, indicated by Office of Production Management information. Present estimates of copper requirement for defense indicate that nearly all the available metal will be required in the future for this purpose. Severe dislocations are, expected, but the objective is to distribute the copper available for civilian use in such a manner as to minimize these dislocations. The advisory committee on metals and minerals has been asked for a suggestions which may be helpful in meeting this situation.\

Jan 1, 1941

By J. S. UNGER

A LARGE proportion of the coke used is made in the by-product oven from the high-volatile coals mined in the adjacent district. At the beginning it was feared good by-product blast-furnace coke could not be made with our coals. By experimenting with various mixtures of coals, coking time, oven design, and coking temperatures, much has already been accomplished. The results show that a hard, dense coke, not easily broken by handling, can be produced. In its present state it is not all that could be desired, but it is being constantly improved. Such coke has been used alone as the fuel on several of the blast furnaces producing the highest daily production in the Pittsburgh district. Many of the coals in the Pittsburgh district when coked in the by-product oven yield a gas which contains a high percentage of sulfur, which is objection- able for many metallurgical operations. As this fuel is gradually replacing the ideal fuel, natural gas, which is becoming less plentiful, studies are being made of the best methods for purification. Some metallurgists believe sulfur to be a very injurious element in steel. Recent investigations by Government bureaus, scientific bodies and private firms, seem to indicate that a reasonable amount of sulfur may exist in steel without detriment. Without wishing to provoke any metallurgical controversy on the subject of sulfur, the fact remains that the daily purification

Jan 1, 1926

More than 400 academic, government, and industry representatives attended the second symposium on ash utilization and technology held in Pittsburgh, Pa., March 10-11, 1970. Sponsored by the National Coal Association, Edison electric Institute, American Public Power Association, National Ash Association, and the Bureau of Mines, the symposium featured 23 formal presentations by leading experts from Europe and the United States on all major phases of ash production, utilization, and research. Abstracts of all the papers are grouped right after this introduction, and the full symposium proceedings follow. Biographical sketches of the representatives are given in an appendix. Sponsoring organizations and their chief representatives were the National Coal Association, James R. Garvey, Bituminous Coal Research, Inc.; Edison Electric Institute, C. E. Brackett, Southern Electric Generating Co.; American Public Power Association, Howard J. Stemm, Columbus (Ohio) Electricity Division; National Ash Association, Inc., John A. Tillinghast, American Electric Power Service Corp.; and the United States Department of the Interior, Bureau of Mines, William L. Crentz.

Jan 1, 1970