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By S. K. Kawatra

Feasibility studies of the on-stream analysis of lead in mineral slurries by S. K. KAWATRA. P. Eng. (Canada). Ph.D. (Australia). M.Sc. (India) (Visitor) Instruments for the measurement of lead in mineral slurries by the use of isotopes can be based on the absorption of Iow-energy gamma rays, backscattering of beta particles, or X-ray fluorescence. The merits of each method are discussed, and the reasons for the selection of the beta-backscattering technique are given. A system using this technique has been designed, constructed, and tested on samples of concentrates from an industrial concentrator.

Jan 8, 1976

By F. L. Misaqi

The total amount of radon-222 released into the atmosphere by the US uranium mines and mills is only an infinitely small fraction of the total amount of radon released by the top layers of soil with a high concentration of uranium, such as is found in Grants, N. M. Even when compared to areas where mineable deposits of uranium are unknown, the amount of radon released by all US mining and milling operations is still relatively insignificant. Of course, higher local concentrations of airborne radioactivity may be observed around stockpiled ore and

Jan 8, 1976

By Stuart A. Bengson

It is extremely difficult to revegetate disturbed sites and mineral wastes in an arid environment because of sporadic and undependable rainfall. Thus, irrigation is often a must for starting seed germination and vegetation. Quite aside from the harsh climate, mining disturbances by themselves cause various adverse conditions for a revegetation program. The problems of revegetating a harsh soil, for instance, are often compounded by the steep slopes of mine wastes. Since these steep slopes intensify the droughty conditions by rapidly draining away soil moisture and accelerating runoff, supplemental irrigation may be the only solution for establishing vegetative cover on the slope.

Jan 8, 1976

By Duane E. Eubanks, David B. McDonald

The anticipated growth of western coal production over the next decade is expected to add approximately 274.3 million t/y (302.4 million stpy) to US capacity. The increased output, coming from both new mines and expansion of existing facilities, promises to bring with it a new set of problems for mine planners.

Jan 8, 1976

Book review Burkin, A. R. (ed.) . Leaching and reduction in hydrometallurgy. London, Institution of Mining and Metallurgy, 1975. £10. hydroxide pyritearsenopyrite NIM reports Report no. 845 A n electron-microprobe study of the nickel distribution in a serpentinite from Volspruit, Potgietersrus. (22nd Oct., 1969; re-issued Dec. 1975). Report no. 1546 Pilot-plant smelting campaign on iron ores from Tete. (22nd May, 1973; re-issued Jun. 1976). Report no. 1557 Cost estimates for the production of pig iron in the Tete district of Mocambique. (18th Jun., 1973; re-issued Jun. 1976). Report no. 1600 Dilute-acid leaching of slag from Tete ore. (20th Nov., 1973; re-issued Jun. 1976). Report no. 1602 The roasting of Tete slag for the extraction of vanadium. (20th Nov., 1973; re-issued Jun. 1976). Report no. 1635 Magnetic separation tests on Tete slag and ore. (30th Apr., 1974; re-issued Jun. 1976). Report no. 1671 Pyrometallurgical retreatment of a slag for the recovery of vanadium. (11th Oct., 1974; re-issued Jun. 1976). Report no. 1785 Some thermodynamic aspects of systems relevant to the flotation of sphalerite. Report no. 1808 Spectrophotometric determination (with pyrocatechol violet as chromogenic agent) of aluminium in zirconium metal and in the residue from anodesludges. Report no. 1813 The economic potential of some pegmatites from the Kenhardt area in relation to the trace-element content of their border zones. Report no. 1817 The rapid determination by X -ray-fluorescence spectrometry of tungsten in tungsten ores and concentrates. Report no. 1820 The thermodynamics of the formation of chlorocomplexes of iron (III), cobalt (II), iron (II), manganese (II), and copper (II) in erchlorate medium.

Jan 8, 1976

"World Mining and Metals Technology" is the title of this year's SME-AIME Fall Meeting and Exhibit in Denver, Sept. 1-3, where a record number of exhibits are scheduled for display. The international theme is particularly appropriate, for in addition to the annual SME session, the Third MMIJ-AIME Joint Meeting will be held.

Jan 8, 1976

Jan 7, 1976

By J. T. Davies

Note: Melting techniques in the iron foundry by J. T. DAVIES* INTRODUCTION The selection of melting equipment for use in an iron foundry has for several years been the subject of numerous discussions, papers, and conferences. The controversy that has raged throughout the world has been brought about by the following factors: IF AC Symposium The 2nd IF AC Symposium on Automation in Mining, Mineral and Metal Processing will be held from 13th to 17th September, 1976, at the Carlton Hotel, Johannesburg. Advance registration takes place on 12th September, 1976. World phosphates The Minerals Bureau of the Department of Mines has released the second publication in its series of reports on the economic aspects of minerals that are of particular importance to South Africa.

Jan 7, 1976

By K. R. Vost

Variation in air temperature in a cross-section of an underground airway by K. R. VOST, B.Sc. (Glas.), M.Sc. (N.S.W.) (Visitor) Measurements of air temperatures in underground airways are normally made at only one point in a cross-section, and the air tem peratures at other points in the cross-section are assumed not to differ significantly from this. This paper discusses measurements made at a number of points in fifty crosssections in airways with different air velocities and wetness of floor. These measurements show that significant variations of air temperature can occur in a given cross-section at a given time. The effects of such variations on the accuracy of measurement of rises in air temperature as air passes along an airway are discussed. The importance of considering experimental error in the measured rises in air temperature when attempting to validate theoretical and empirical methods of predicting such rises is also discussed.

Jan 7, 1976

In late May, at its final session in Nairobi, Kenya, the UN Conference on Trade and Development (UNCTAD) narrowly rejected the US proposal for a new International Resources Bank suggested by Secretary of State Henry Kissinger. The proposal was defeated by a roll-call vote of 33 to 31, with most of the nay votes cast by communist countries, and with 89 of the less-developed countries abstaining or absent.

Jan 7, 1976

By J. F. Harvard

We might say that for the metallurgist time "ambles withal," for the mining engineer time "trots withal," and for the geologist, time "gallops withal." And anyone for whom time "stands still withal" does not belong in the mining community today! In this bicentennial year of the United States of America we sense the mystery of time and we feel the pulse of history, especially in our own profession. What was mining like 200 years ago? What is it like today? What will it be like 200 years in the future?

Jan 7, 1976

By H. M. Friede, R. H. Steel

Tin mining and smelting in the Transvaal during the Iron Age by H. M. FRIEDE*. Ph.D. and R. H. STEEL* (Visitors) This paper reviews the historical, archaeological, and metallurgical evidence on Iron Age tin mining and tin smelting in Southern Africa. The results of the analysis of twenty samples of tin ore, tin slag, and tin ingots found associated with Iron Age materials in the Transvaal (mostly in the Rooiberg area) are reported and discussed. The types of ingots preserved in local collections are described. A small experimental tin-smelting furnace was constructed and worked according to traditional African Iron Age technology. Qualitative and quantitative results of this experiment are reported.

Jan 7, 1976

Jan 7, 1976

By Eugene Guccione

FOREWORD-At the SME-AIME meeting in Las Vegas this year, the SME Publications Board and the MINING ENGINEERING Committee decided that a fitting way of celebrating the United States' bicentennial would be to publish an article in ME covering the great men in American mining. After some discussion as to the inclusion of financiers -men such as William Randolph Hearst, J. Pierpont Morgan, etc.-the group agreed that the feature should be restricted to the "nuts-and-bolt people," e.g., mining engineers, geologists, mineral processing engineers. Thus, from the AIME All Institute Honors roll and from the SME Awards list, the group chose these 11 historical figures: Herbert Hoover, Daniel C. Jackling, Henry Krumb, James Douglas, Rossiter W. Raymond, Hal W. Hardinge, Seeley W. Mudd, Erskine Ramsay, Howard N. Eavenson, Robert A. Richards, Arthur F. Taggart. What follows is an account of each of these great miners' achievements and the problems they faced, and an assessment by some of today's mining leaders of the challenges that lie ahead.

Jan 7, 1976

By Ta M. Li, Russell A. Carter

The first century of mining in northern Idaho's Couer d'Alene District will soon he drawing to a close. Like so many other great raining districts, it has been a period accompanied by a rich and colorful history. From its early days as a gold rush camp, the district has evolved into the leading silver producer in the US, but the going has not been easy: early-day labor disputes, the challenge of mining for profit in some of the deepest mines in the Western hemisphere, and the constant search for new reserves at great depths have taken their toll of mines-and miners-along the way. To these traditional mining problems have of late been added the burden of inflationary cost increases, pollution control, and reclamation. A recent visit to the district by MINING ENGINEERING, how ever, revealed that the deep commitment of the operating companies and the quiet competence and vitality of their engineering personnel are key factors in the continued prosperity of the district.

Jan 7, 1976

By N. B. Strydom, P. L. Jooste, H. F. Kotze, W. H. Van Der Walt

Note: A revised method of heat acclimatization by N. B. STRYDOM, W. H. VAN DER WALT, P. L. JOOSTE, and H. F. KOTZE INTRODUCTION Climatic-room acclimatization was introduced in the gold-mining industry in 1965 and was rapidly adopted by all mines because it reduced the number of days required for heat acclimatization from 12 to 8. The method has been adequately described in previous papers1, 2 but, briefly, requires four hours of heat exposure per day while the work rate is progessively increased from 35 W on Day 1 to 70 W on Days 7 and 8. Several attempts to shorten

Jan 6, 1976

By J. P. Dreyer

Note: The development of AGIT AIR flotation machines by J. P. DREYER HISTORY The first AGITAIR flotation machine was developed and patented in 1932. It has a capacity of 5 ft3t and was named the No. 20. Next in line was the No. 24. Built in 1933, it had twice the capacity of the No. 20 unit. Then, in 1934 and 1939 came the No. 36 (22,5 ft3) and No. 48 (40 ft3) respectively.

Jan 6, 1976

By P. R. Jamisch

The limitations of gold-mine evaluation by P. R. JANISCH, B.Sc. (Sur.) (Natal) (Visitor) Inherent uncertainty in the choice of parameter values places theoretical and practical limitations on the interpretation of a gold-mine valuation that are not necessarily removed by comparison of two valuations on the same assumptions. These limitations arise mainly in the estimates made of cost inflation and gold-price escalation, and lead to inconsistencies in the 'league table' method of investment analysis. The choice of discount rate is also critical in many cases. An approach to the overall problem that takes these limitations into account is suggested.

Jan 6, 1976

By Eugene Guccione

Fear of inflation is one important reason for the rebirth of interest in the stock market, and natural resources are the best investment in an era of rapid inflation.

Jan 6, 1976

An experiment substituting pneumatic crawler drills for large-diameter rotary rigs in overburden stripping operations has indicated significant bit cost savings for Perry and Hylton Coal Co., Beckley, W. Va. The test was conducted in the Egeria Mountains (part of the Appalachian Range), where about 30 m (100 ft) of overburden consisting of hard, seamy sandstone and shale must be removed to recover a 560-mm (22-in.) vein. Perry and Hylton operates ten surface mines and is presently developing three more for start-up in the near future. The company follows a progressive policy toward ecological concerns, incorporating a self-imposed systematic mining and reclamation program for mined lands which leaves the landscape in a suitable condition for further development by local communities.

Jan 6, 1976