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By AIME

A NATIVE son of Salt Lake City. David Douglas Moffat has contributed greatly to both the mineral industries and civic progress in the State of Utah. He was born in 1880 and his whole life bas been intimately associated with mining and milling. His father, one of Utah's pioneer mining men, was superintendent of a mill at Park City. When Moffat was only 18 years of age he went to Philipsburg Mont., where he spent several years as a machinist, and later as master mechanic for the Granite Bi-Metallic Mining Co. He returned to Park City in 1903 as master mechanic and night mill foreman for the Ontario Silver Mining Co. After a few years of varied experience he became, in 1910. general foreman of the Boston Consolidated Will at Garfield, Utah.

Jan 1, 1947

By F. E. Bash

IN recent years, there have been a number of experiments conducted to determine the rates of heating and cooling of various sizes and shapes of steel ingots. Up to date, however,-most of the published data has dealt with small sized ingots, the largest being an 18-in. (46 cm.) cube, the data on which was presented before the Iron and Steel Institute in May, 1918, by E. F. Law. It is due to thus lack of information on the rate at which large ingots absorb heat and come to temperature that the heating- practice varies so widely in different plants. One of the questions over which there is much debate is the proper rate of heating of large ingots for forging and the time actually required for the center of a mass of steel to come to forging temperature. As a continuation of experiments described by M. E. Leeds1 and at the request of Mr. G. R. Norton of the Sizer Forge Co. and Mr. R. C. Drinker of the Emergency Fleet Corpn., the test described in this paper was carried out on a 24-in. (61 cm.) round ingot and the rate of heating and cooling determined under regular production conditions. The ingot had been partly forged at one end but, on developing a flaw, had been scrapped so that it was available for test. The size and shape of the ingot and its position in the furnace are shown in Fig. 1.

Jan 9, 1919

By Lee M. Morris

The Pittsburgh bed, lying at the base of the Monongahela series, is probably the most famous bituminous coal bed in the world; famous not only for the product yielded in mining, but also as a key horizon in the search for oil and gas. It is the most important coal bed in northern West Virginia from the standpoint of extent, thickness and regularity. The general section is shown in Fig. 1. Roof Strata The strata that superimpose any coal bed vary more than the coal itself, and the Pittsburgh bed is an excellent example of 'this fact. Obviously, there were several changes during the period of deposition of this overlying material. Locally, sandstone occurs above and in contact with the coal. Sometimes a shale, or a clayey shale, rests on the bed and is often overlain by sandstone. Throughout the greater portion of northern West Virginia, however, the basal member of the immediate roof is a black or gray clay, which is usually slickensided. This material is called "draw-slate" by the miner. The color is due to the carbonaceous matter and the slickenside is the result of pressure, or movement, which may have come during or subsequent to its consolidation. This part of the roof requires especial consideration, because it is not self-supporting after the coal has been removed from beneath. The roof coal, 8 to 24 in. thick, is left directly below the draw-slate to support it and also to protect the clay from changes in temperature and moisture in the air, thereby preventing disintegration. The clay or draw-slate quickly changes its physical character when exposed, and falls if it is not adequately supported. Timbers alone are not effective in holding up this material, because it softens, crumbles and falls around the supports. Timbers hold up only the material that is directly over the posts and crossbars. In Monongalia County In the northeastern part of Monongalia County, between the Monongahela and Cheat Rivers, sandstone is usually found immediately above

Jan 1, 1931

By AIME AIME

THE following compilation of State bureaus and officials that deal with mineral resources is compiled in part from a new "Check List of State Agencies and Officials Concerned with the Management of Natural Re- sources," compiled for the National Resources Committee, Washington, D. C., by Clifford J. Hynning. Alabama-Geological Survey of Alabama, University. Walter B. Jones, State Geologist. Chief Mine Inspector: W. B. Hill- house, 614 Lincoln Life Bldg., Birmingham.

Jan 1, 1939

By A. B. Kinzel

THE year 1936 has been an eventful one in the iron and steel industry. Renewed industrial activity has brought with it many new problems. These problems have generally involved the question of increasing capacity without sacrifice of economies and quality developed in the less active previous years. The nature of the iron ore used and the effect of its porosity and other physical characteristics on the capacity of the blast furnace has been reviewed by the U. S. Bureau of Mines. The whole question of handling raw materials and methods of charging furnaces has been intensively studied, with the result that capacity has been in- creased without affecting the quality of

Jan 1, 1937

By W. C. Peters

Geologists take the role of mine geologist when they apply their science to the design and operation of a specific minerals project. In doing so, they use the entire spectrum of procedures in economic geology and engineering geology to deal with a specific system of orebodies and associated environment. The objectives are established by stages in the life cycle of a mining operation as it goes from a prospect to a development project and on to a mine. This paper summarizes the elements of a mining geologist's role, with examples highlighted from the preceding papers.

Jan 1, 1984

By H. Siebert, G. Raitt

With the advent of the Interstate Highway Pro- gram, many problems have been encountered in the application of highway design standards to topography, particularly rock cut design. A rigid application of slope ratios with little respect to rock type, dip, foliation, structure and height of cut face is a problem. Generally a slope ratio of ½ : 1 or 63º for shallow cuts and 1/3: 1 or 71º in deeper cuts are used in Connecticut. The deepest cut face constructed recently was greater than 185 ft. With cuts of this size, rock fall and stability become a problem, and a way to reduce the problem is to construct a stable face initially. A search of the literature indicates that adequate information on the construction of stable rock slopes is not available. A major highway contract was awarded in 1962 to Savin Brothers, Inc., in which line drilling on 6-in. centers was required in many portions of the contract where the cut was greater than 60 ft and one or more benches were to be constructed. From the start of the project many variations were attempted regarding slope hole spacing and distribution of explosives in the holes. Rock ranged from a competent granitic gneiss to an incompetent soft graphitic schist. Generally, the roadway alignment was roughly normal to the strike of the foliation having a dip of ± 60º. An important factor affecting construction of rock slopes was the existence of intersecting joints and faults. The spacing used in less competent rock was about one ft on center. Loading of holes was purposely varied. As competency of the rock increased, hole spacing was also increased. Thus, on a different project in similar rock, spacing was kept at 4 ft.

Jan 4, 1966

By W. W. Loo

A REVIEW of the literature on the reduction of cassiterite showed. that scarcely any progressive changes were made in the methods of reducing cassiterite until within the last two decades, and that during that period many improvements in the metallurgy of tin have taken place. Since 1914 the world's consumption of tin has increased considerably, resulting in the exploitation of primary tin deposits such as the Bolivian lode, which has become an important source of tin. On account of the low tin content of Bolivian ore, and the presence of objectionable impurities of the reduced tin, the smelting of this ore and the refining of the tin has changed considerably from the methods formerly used. A comparative study of the methods of smelting cassiterite concentrates suggested that an investigation be planned so as. to determine what factors effect the extraction of tin from its ores by reduction with carbon. The first part of the experimental work was the determination of whether roasted cassiterite concentrates can be reduced by carbon without the use of flux, and the reduced pellets of tin be collected into a single mass separate from the dry gangue residue The second part of the experimental work was a comparison of the effect of variations of the different factors on the smelting of roasted cassiterite concentrates: first, the effect of varying the composition of the slag; second, the effect of varying the amount of reducing agent; third, the effect of varying the relative amount of the resulting slag; and fourth, the effect of different kinds of reducing agents:

Jan 1, 1928

By Georges Millot

USUALLY the search for clays is left to chance in unexplored areas. A local working by the inhabitants or an outcrop is often the only guide. If the conditions of genesis of clays were always known, a set of general rules could be drawn up that would apply to this search. For example, a certain type of clay might be found wherever the sediment indicated a favorable environment. This paper sums up the considerable amount of knowledge that has been accumulated about the genesis of sedimentary days and offers some rules to be observed in prospecting for new clays. ANALYTICAL STUDY OF SEDIMENTARY CLAYS Clays may be found in many formations, both recent and ancient. All the intermediums exist between the deep-sea deposit and the mud deposited by a stream. In order to find out whether the nature of clay deposits depends on the environments in which they were formed, the samples used in the investigation described herein were very carefully chosen from: (1) ancient sedimentary series (a few from recent ones), (2) zones where conditions of genesis are typical. Ancient Formations Ancient formations were chosen because they are less difficult to sample than the bottom sediments of present-day lakes and seas. Moreover, a geo- logical section makes it possible to define the conditions of genesis of a deposit based on its facies, fossils, stratigraphic relations, and paleography. A present-day deposit is defined only by its aspect at the moment. Its previous history may have caused mixtures, alterations, and changes of environment, which escape detection. Typical Conditions of Genesis Samples from ancient deposits were taken from zones where typical conditions of genesis prevailed. Only clays from marine, lagoonal, and lacustrine environs are concerned in this study because the nature of the original en- vironments could be affirmed. In this way an inventory of the nature of sedimentary clays has been made for rocks formed in typical and individual environments; therefore the extent of the results that may be drawn from such a study will need discussion.

Jan 1, 1952

By B. B. Zavoico

Considerable progress has been made during the past year throughout the Russian petroleum industry. Perhaps the most remarkable achievement is the execution of the programs set out by the Central Planning Bureau of the Department of Commerce. These programs have been increased twice during the past operating year, necessitating drilling the richest reserves, instead of developing gradually as originally planned. The fulfillment of the set-out programs during the past few years makes therefore the present five-year plan of considerable importance to the international oil statisticians in approximating actual supply conditions up till 1933. The production of all Russian fields increased by 14,200,000 bbl. as compared with the 1927-1928 operating year, while the next year's program anticipates a further increase of 15,700,000 barrels. It appears therefore that production for 1932-33 will total 187,000,000 bbl., or approximately double that of the operating year just closed. It is also evident that the old fields are counted upon to produce only about 67 per cent. of the total, the new fields, not yet discovered, to furnish the balance of 33 per cent. The Soviet oil leaders therefore are hoping to have new fields discovered and developed by 1932-33. However, as in the past wildcatting

Jan 1, 1930

By J. C. McHardy

During 1980-2000, the Florida phosphate industry will deplete its central Florida Polk County reserves. As a result, new mines will be built in the so-called southern Florida reserve areas. These mines will require new mining, beneficiation, and tailings disposal technologies since southern reserves have different characteristics than have been encountered in the central Florida deposits. Furthermore, government regulations will necessitate development of new tailings and clay disposal methods. This paper reviews these challenges for the Phosphate industry and how these opportunities can be expected to effect plant design and plant operating practices.

Jan 1, 1984

By Harry Roeser

Short cuts for determining the constants of oil decline curves, with the method of least squares as a starting point, are presented and applications made to practical examples. The nature of the raw data does not justify rigid adherence to the orthodox theory but does lend justification to convenient methods of approximation within reasonable limits. If the conventional form y = kxn were changed to y = k(x + c)', methods of determining the curves would be simplified and greater uniformity in calculated results would probably follow. As A result of the publication, several years ago, of some articles on determining the constants of empirical formulas, the determining the constant's of types of curves used for estimating the production decline of oil wells was brought to the writer for study. Methods requiring a minimum of time and labor and a maximum of rigor were sought, as it appeared that the nature of the data from which such curves are computed and the relative uncertainty of occurrence of the events predicted from them did not justify close adherence to the theory on which the solution of such problems is ordinarily based. The technical deficiencies of the solutions presented in this paper, from the standpoint of the method of least squares, are readily apparent to those familiar with that method, but their presentation in detail here is irrelevant to the subject matter. However, it is the author's conviction, after a rather exhaustive study of the problem, that the value of the solutions lose little by the approximate application of the conventional theory. It must be understood by those who use these formulas that the solutions herein given, and the formulas based on them, are merely facilities to aid the valuation engineer in forecasting future events. It is assumed, also, that before application is made of them, prescient judgment based on the circumstances in each case, shows that the forecast has some probability of realization. On this basis only will these formulas be found useful.

Jan 6, 1924

Jan 1, 1902

By A. H. Tousley

The cement industry is on the horns of an economic dilemma. Within the last ten years, its over- capacity in the United States has varied from 139- 127% of demand (Fig. 1). The most direct effect of this is seen in cement prices, which reached a peak in 1960, retreated steadily through 1966 and only recently climbed back to the 1960 level again. With prices in a slump and production costs estimated to be up almost 30%, there has been a steady drain on cement profits. Since 1960, labor costs have increased 86% while fuel costs have risen 18%. Meanwhile, customer service costs have also soared owing to the competition for cement customers and the wider variety of available cement products. This search for sales advantage has in turn led to a higher Blaine number, which means more grinding and hence bigger mills, more power, and, once again, higher costs. New plants as well as expansions and revisions to existing plants are also costing more owing to higher

Jan 1, 1971

By H. P. Allen

THE Achotla mill of the Cia. Minera de Peñoles is of special interest in that it is one of the few still employing the chloridization process. The ore milled comes from the Suriana mine and consists of both oxide and sulphide, from neither of which can the gold or silver be extracted by a simple cyanide treatment. The mill was built in 1927, after several years of study in the development of the process1, and operated from December of that year until October 1930. Operations were resumed in February 1935, and have been continuous since, treating approximately 5000 tons per month, while the mine is getting up to full tonnage of 6500 tons per month.

Jan 1, 1937

By S. K. Ruggieri, R. A. Jankowski

Airborne respirable dust levels on longwalls can be reduced if operators approach the dust control problem in a logical and fundamental manner. This can be accomplished through the proper application and continued use of effective dust control techniques. The Bureau of Mines is currently assessing the effectiveness of longwall dust control techniques in use today to provide mine operators with guidelines for selecting the most appropriate control technology. This paper presents a fundamental approach to the problem of shearer dust control. Three dust control techniques to be discussed are: deep cutting/increased pick penetration for reducing the amount of respirable dust generated; drum water sprays/improved water supply system to suppress the amount of airborne respirable dust; and improved external water spray system, the “shearer-clearer, "to push the dust close to the face. The techniques have been evaluated infield trials and have been shown to be both practical and effective in applications to control shearer generated dust.

Jan 1, 1985

No. 275. Chemist, assayer, and precipitate smelter, also an experienced shift man; both for a cyanide plant in Peru. Salary £30 Sterling per month; two years' contract and all traveling and living expenses. No. 276. Metallurgist; experienced in reducing tungsten ores and preparing metallic tungsten and tungsten alloys. No. 277. Draftsman and transitman for coal mine work in Middle West. Salary $125 per month. No. 278. Metallurgical engineer familiar with microscopic work and experienced in making microscopic photographs; with some experience in heat treating of alloy steels. No. 279. The Trench Warfare Section of the Ordnance Department desires to get in touch with young men over draft age, or in deferred draft classification, who are physically sound, who can. become candidates for commissions; earning capacity of at least $1700 a year. Must have good character, some business experience, university training, and some technical skill. Application should be made to Captain Hudson Millar, 1800 Virginia Avenue, Washington, D. C,. Three original letters of recommendation from American citizens must be furnished. An appli-

Jan 3, 1918

INTRODUCTION TO SAMPLING THEORY Before specifically discussing mineral sampling and sampling procedures, let us briefly consider broader and more universal concepts of modem sampling theory. A sample is de- fined as a representative part or a single item from a larger whole, being drawn for purpose of inspection or shown as evidence of quality. In modem theory the sample is a part of a statistical population whose properties are studied to gain information about the whole. The theory of sampling is built around the concept that if enough representative units of a larger overall population are selected without bias, the average value of the units will approximate that of the total population. Modem theory attempts to answer the question of how many samples are enough, given certain limits and constraints, and seeks to apply methods of sample selection and of estimation that provide, at the lowest possible cost, estimates that are precise enough for the purposes at issue. In order to meet these objectives the designer of a sample survey must rely heavily upon statistical theory. Statistics has been defined as the collection, presentation, analysis, and interpretation of numerical data. Statistical methods are primarily concerned with making valid inferences about a population based upon samples taken from the population. For most statistical applications, the total sample is in terms of number of items, attributes, or things; whereas mineral samples are usually in terms of weight or volume of mineral particles. Certain steps are involved in a well designed sample survey without regard to the particular field of application. Because the desired characteristics of an unmined mineral deposit can- not be known other than by sampling, we will consider these principle steps in terms of a mineral sample survey: 1) Clear definition of the objectives of the survey. In the case of mineral sampling this step is so apparent as to be almost ridiculous. However, it is surprising how often the overall objective of a sampling program is overlooked when decisions are made on a day-today basis. 2) Definition of the population to be sampled. The word population is used to designate the aggregate from which the sample is chosen. A sampling program may be designed to determine the grade of a single stope within a mine, the grade of a particular zone within a complex ore body, or the total value and extent of a mineral deposit. Since mineral sampling is usually done in phases, it is well to

Jan 1, 1980

By J. Donald Graham, John G. Kuhn

The goal of any development drilling program is the drilling of the exact number of holes necessary to adequately determine grade and dimensions of an ore body, no more and no less. Any technique which eliminates unnecessary drilling costs produces beneficial results, both to the company and to the person who can claim the savings. The method for controlling development drilling programs to be described was developed during the latter part of a major development drilling project at the Christmas mine of Inspiration Consolidated Copper Co. in Gila County, Arizona. It was used to test the need for drilling individual holes but could be expanded to control an entire project. Application of this method involves an evaluation of geological conditions present and a good bit of common sense. Projects involving large disseminated, rather homogeneous ore bodies of the porphyry-copper type would be the most likely candidates for application of the technique. Discontinuous ore bodies would not be amenable. The method is based on the measurement of the linear correlation between the spatial distribution of two sets

Jan 1, 1973

By M. S. King, B. N. P. Paulsson

Four vertical boreholes in the vicinity of an electrical heater simulating a canister of nuclear waste in a granitic rock mass have been logged with an acoustic borehole sonde before and after thirteen months' heating. Excellent control of the structural geology and fractures present in the rock mass was provided by the considerable amount of oriented core recovered from the four boreholes used for acoustic logging and the large number of others used for a variety of rock mechanics instrumentation. Compressional and shear-wave velocities were measured as a function of stress on some twenty core samples, water-saturated and dry, which were recovered from the four acoustic logging boreholes. Further control was provided by a cross- hole acoustic monitoring program conducted before, during and after heating between the same four boreholes, and by measurements of acoustic velocities in an isolated block of granite in the same heater drift, which was subjected to an increase in temperature and to changes in uniaxial stress. It is concluded from the acoustic logging tests, taken in conjunction with the acoustic cross-hole and heated block experiments, that acoustic techniques: 1. Provide a means for locating and delineating systems of weakly- bonded or open fractures within the rock mass; 2. Provide a sensitive means for monitoring a rock mass for changes in moisture content or structural damage to the rock fabric induced by thermal or mechanical loading; 3. Together with the rock bulk density yield the elastic constants of the rock mass.

Jan 1, 1982