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By K. Barron

The glass insert stressmeter, or photoelastic stressmeter, is an instrument designed to determine stress changes occurring in rocks. It has several potential advantages over other such devices in that it is a biaxial device, it is simple and it is cheap to make. The object of this study was to assess the behaviour of the meter under biaxial loads and to examine some of the problems associated with measurement and interpretation of the fringe pattern. This assessment has been carried out by comparing theoretical and laboratory behaviour of the meter. It has been shown that: a) There are certain optimum measuring points in the meter at which measurements should be made for best accuracy. The position of the points depends on the ratio, n, of the biaxial stresses. b) The meter&apos;s sensitivity can be assumed to be independent of the rock modulus E provided that the rock modulus is < 2.5 x 106 psi and not, as previous workers have assumed, if E < 5 x 106 psi. c) There are several methods of separating the principal stresses; some of these are unsatisfactory. A new method is proposed and discussed. d) The meter sensitivity decreases as the ratio of the biaxial stresses approaches unity; the accuracy thus also decreases. e) The axes of symmetry of the fringe pattern give an excellent indication of applied stress direction. f) Laboratory calibrations are in good agreement with theory. The glass insert or photoelastic stressmeter is an instrument designed to determine stress changes occurring in rocks. It has several potential advantages over other such devices in that it is a biaxial device, it is simple and it is cheap to make. This stressmeter has been described in detail.l,2 Basically it is a hollow glass cylinder that has at one end a light source and filters producing circularly polarized light. The glass cylinder and source are grouted into a borehole in rock and the face of the cylinder is viewed through a quarter wave plate and an analyser. If, after installation, a stress change occurs in the rock, then a distinct colored isochro-matic fringe pattern is seen in the meter. The fringe order at any point in the meter can be determined by counting the fringes and measuring the fractional fringe orders by the Tardy compensation method. The relation between the fringe order at any point and the applied stress change can be determined either by calculation or by calibration. The object of this study was to assess the behavior of this stressmeter under biaxial loading conditions and to examine some of the problems of interpretation of the fringe pattern. THEORY Hiramatsu et a14 have determined the stress distribution in a hollow cylindrical inclusion in an elastic host material when subject to uniaxial stress. Using this solution, the biaxial case of stress p in the x direction and stress q in the y direction (Fig. 1) can be solved by superposition. This has been done in Appendix 1. It is shown that the principal stress difference (s1 -s2) at any point (r,?) in the cylinder is given by:

Jan 1, 1965

By G. J. Saulnier, K. E. Goddard

The US Geological Survey has developed mathematical modeling techniques to assess potential impacts on the hydrologic system resulting from mining of coal and oil shale in northwestern Colorado. Potential impacts of oil shale mining on groundwater hydrology have been simulated using a quasi-three-dimensional, finite-difference model. The model has been used to simulate hypothetical mine dewatering operations at two proposed oil shale mines. Dissolved-solids distribution and solute transport were simulated with a three-dimensional, finite-difference model that was used to evaluate the effects of flooding in hypothetical abandoned mines. The potential impacts of coal and oil shale mining on water-sheds were investigated using a digital watershed model. This deterministic physical-process model predicts responses of the hydrologic system to modifications resulting from mining in basins having snow as the major source of runoff and recharge. Potential impacts of coal development on surface water quality were investigated using a river quality assessment model. The models developed by the US Geological Survey have been useful in defining the potential effects of mining in northwestern Colorado. They are an important first step in analyzing the existing data base and in predicting impacts and new data needs. The models may not be totally applicable on the local scale but are very meaningful on the regional level.

Jan 1, 1983

Jan 1, 1904

By George Rice

THE A.I.M.E. Ground Movement and Subsidence Committee, pro-posed in 1920, held its first technical meeting in February 1923, under the able chairmanship of Mr. H. G. Moulton. The following list of papers and discussions, indicating the scope of the problems and relation to various conditions and method of mining, were given at that meeting by the distinguished mining engineers: J. Parke Channing, on Subsidence at Miami, Arizona; Howard N. Eavenson, on Mining an Upper Bitu-minous Seam after a Lower Seam Has Been Extracted; J. J. Rutledge, on Subsidence in Two Oklahoma Coal Mines; Benjamin F. Tillson, on Caving Cracks at the Franklin Mine, New Jersey; Dr. F. W. McNair, on the Dome Theory; William Kelly, on disadvantageous effects in Mining and Back-filling Working Upward a Steep-Pitching Iron-ore Bed; Eli T. Conner, on the good results of Back-Filling by Hydraulic Means in Preventing Destructive Subsidence in the Anthracite District; Thomas H. Claggett, on the merit of Systematic Pillar Drawing in Preventing Cracks in an Upper Seam; Henry H. Otto, successful results in the anthracite district in Mining Lower Seams before Upper Seams; Douglas Bunting, on Leading Factors Incident to Successful Mining of an Overlying Seam; Edwin Ludlow, on there being "less damage to buildings when there was complete removal of coal with complete packing than when room and pillar is used without extracting the pillars"; Edward O&apos;Toole on "bumps" in eastern Kentucky mines, which he thought were the result of geologic stresses: H. A. Buehler, on Upheaval of Surface in an Illinois Case in Advance of the Face; and R. Dawson Hall, on The Mechanics of Subsidence from Mining. The author of this paper discussed various Winds of problems of ground movement and subsidence in both metal mining and coal mining; the production of great landslides by workings near an outcrop, as at Turtle Mountain, Alberta, Canada; and general

Jan 1, 1939

By George W. Neumann

The mines and concentrator of Brunswick Mining and Smelting Corporation are located in the northern part of the province of New Brunswick, approximately 20 miles distant from the City of Bathurst. Discovery of the No. 6 orebody by diamond drilling in 1952 was followed by the finding in March 1953, of the larger and higher- grade No. 12 orebody, approximately six miles to the north of the No. 6 deposit. Original development was financed by St. Joseph Lead Co., and included a small open-pit operation with a 10C ton per day pilot mill at No. 6 orebody, shaft sinking and underground development at No. 1; orebody, and an extensive program of laboratory and pilot plant metallurgical research on No. 12 ore. These operations were suspended in May 1958, and remained in standby condition until June 1961, when the equity of St. Joseph Lead Co. was purchased by a group headed by M. J. Boylen, K. C. Irving, Maritime Mining Corporation, and the Patino Corporation. Construction of a mine plant and concentrator at the No. 12 mine commenced in October 1962 and the concentrator was placed in operation in March, 1961b. Preparation of the open pit mine for production, construction of the No. 6 Concentrator to produce bulk Pb-Zn-Cu-Ag concentrate from No. 6 ore, and construction of an Imperial Smelting Process smelter at Belledune were started in 1964 and placed in operation in September 1966.

Jan 1, 1970

By Walter W. Bradley

(Three, papers included, in this discussion are classified as Mining Geology and also as one of the following-A, Metal Mining: B, Milling and Concentration: L, Geophysics. These papers are TP 2255, TP 2092 and TP 2038.) CONTENTS [PAGE Review of Fluorescence as Applied to Minerals, with Special Reference to Scheelite. (TP 1967 by J. W. VANDERWILT, Min. Tech., March 1946. Discussion by WALTER W. BRADLEY) I Geologic Interpretation of Magnetic Exploration on the Mesabi Range, Minnesota. (TP 2038 by R. B. H. JONES, Min. Tech., July 1946. Discussion by ROBERT B. SOSMAN) I A Technique for Photographing Difficult Subjects through a Petrographic Microscope. (TP 2092 by DONALD W. SCOTT, Min. Tech., Nov. 1946. Discussion by HORACE WINCHELL) 2 The Search for Concealed Deposits-a Reorientation of Philosophy. (TP 2146 by SAMUEL G. LASKY, Min. Tech., May 1947. Discussion by T. M. BRODERICK)3 Occurrence of Lead-zinc Ore at Iron King Mine, Prescott, Arizona. (TP 21 go by H. F. MILLS, Min. Tech., July 1947. Discussion by HUGH M. ROBERTS)3 Geologic Relations and New Ore Bodies of the Republic District, Washington. (TP 2197 by LAWRENCE B. WRIGHT, Min. Tech., July 1947. Discussion by AUGUSTUS LOCKE and J. A. RICHARDSON) 4 San Manuel Prospect. (TP 2255 by H. J. STEELE and G. R. RUBLY, Min. Tech., Sept. 1947. Discussion by L. KENNETH WILSON, ELDRED D. WILSON and the author) 5] Review of Fluorescence as Applied to Minerals, with Special Reference to Scheelite WALTER W. BRADLEY*-AS I recall, the first portable units for ultra-violet light of practical use with scheelite were developed at the Nevada-Massachusetts Tungsten Mine at Mill City, Nevada, and were used underground. Ultra-violet lamps are also installed there in the mill, above the gravity-concentration tables, for control observations. Geologic Interpretation of Magnetic Exploration on the Mesabi Range, Minnesota ROBERT B. SOSMAN*-When artificial precipitated magnetite is oxidized at a temperature in the vicinity of 100°C, the oxide is converted into a chocolate brown ferric oxide of the formula Fe2O3, free from ferrous iron, yet possessing the same magnetic susceptibility as the original Fe3O4. This form of Fe2O3 is variously called "ferromagnetic ferric oxide," " maghemite," or "gamma ferric oxide," and has been found as a natural mineral. If a body of magnetite in the Biwabik were to oxidize to this form, the oxidized and leached ore body might successfully conceal itself from Mr. Jones&apos; survey by this ferromagnetic pretense. So far, gamma ferric oxide has not been found on the Minnesota iron ranges. I thought I had found some in the Hibbing pit in 1940, in a strongly magnetic specimen of soft ore differing in color from the prevailing hematite

Jan 1, 1947

By B. G. Klugh

In a paper before the Institute at Wilkes-Barre, Pa., June, 1911,&apos; Mr. James Gayley discussed the application of this process to iron-bearing materials. The same author² described the results of operations at the plant at Birdsboro, Pa. The purpose of the present paper is to present further discussion of some techuical details involved in the operation of this plant, and of the theoretical and practical relations of this product to blast-furnace practice. Since Oct. 1, 1911, the Birdsboro plant has been in operation at the blast-furnace of the E. & G. Brooke Iron Co. The results have been highly satisfactory, although the material treated, being chiefly the flue-dust currently made by the furnace or taker] from the accumulated stock-pile, was excessively high, and yet not uniform, in carbon, so that the desirable control or regularity of the amount of fuel in the mixture treated could not be maintained. Nothing could more forcibly demonstrate the flexibility of the process than the fact that, under these conditions, the sinter produced was, in all cases, of excellent quality. The Dwight & Lloyd process, as such, slid its present highly-developed mechanical appliances were described by Mr. Gayley in the paper above mentioned. While the repetition of some particulars will be unavoidable in this paper, it will be confined to features bearing upon the metallurgical principles involved. According to the principle of the process, the finely-divided iron-bearing material to be sinterecl is intimately nlixed with

Jan 1, 1913

Full details of the program for the New York meeting .were given in the January Bulletin and the announcement mailed to members. The following brief synopsis is offered simply as a reminder of the principal events of this meeting which Chairman Browne says is going to be "different." Time.-Monday, Feb. 14, to Thursday, Feb. 17, 1916, inclusive. Place.-Engineering-Societies&apos; Building, 29 West 39th St., New York. Events.-Monday, Tuesday and Wednesday (Morning and Afternoon) Technical Sessions. Tuesday, 10 a. m.: Annual Business Meeting, Luncheon served in the-Engineering Societies Building between sessions each day.

Jan 2, 1916

By Arthur F. Taggart

The following notes represent significant excerpts from a mass of records of experimental work done in the ore-dressing laborattory at the Columbia School of Mines during the years 1926 to 1928 inclusive. Classification of Experimental Work The experiments performed may be grouped for purposes of description under the following general headings: I. Collecting agents. a. A method for quantifying collecting effect. b. Coating with undissolved collecting agents (oils). c. Action of dissolved collecting agents. II. Frothing agent&apos;s. a. A method for quantifying frothing effect. b. Relation between frothing effect and chemical composition. III. Inorganic reagents. a. Methods of studying the effects of these reagents. b. Effect on slime dispersion. c. Effect on sulfides. Summary of the Origins of Present-day Flotation Practice The first practicable, foolproof method of froth flotation was described in U. S. Patent 835120, issued in 1906 to Sulman, Picard and Ballot, and in the equivalent patents in other countries. A number of less simple methods of producing the same result had been described previously in patent publications and otherwise.&apos; The reagents specified in all of these early patents were "oils" and, in addition, some inorganic substance, usually an acid. The quantities of reagents recommended and added were enormous when compared with those used today.

Jan 1, 1930

By W. G. Fischer

Basic laboratory tests on trona and the surrounding shales initiated the Rock Mechanics program. The stress-strain curve, modulus of elasticity, Poisson&apos;s ratio, the uniaxial rock strength, Mohr&apos;s envelope, the biaxial stresses at failure, and creep were investigated. A series of underground problems were then approached using this information and various field measuring devices, most of which were developed by the Bureau of Mines. Initially, stress concentrations near mine openings were evaluated using the stress relief technique. This required an accurate determination of the pre-mining stress field. Later, stress concentrations associated with the cave line were studied. After about 30 stress reliefs over an appropriate time interval the effects of one type of mining could be compared against another. The microseismic technique was used to investi- gate a possible application of warning devices near the cave line. A study of mine reorientation was made. Problems related to the shape and size of pillars and barriers were studied. The effectiveness of roof bolting patterns was examined. Control of roof stresses was attempted. A new system of mining in heavy ground has been developed using the information secured in the Rock Mechanics program. Without this system, mining in more than one instance would have been next to impossible. Indeed, from this one discovery alone, the Rock Mechanics program has paid off in improved safety as well as in dollars. The Westvaco trona* mine is located near the town of Green River in the southwestern corner of Wyoming. It is owned and operated by FMC Corp. on land leased from the US Government, the State of Wyoming, and the Union Pacific Railroad. A conventional room and pillar system is being used, (Fig. 1) with complete removal of the pillars during final mining. Return air bleeders surround

Jan 1, 1964

By Philip M. McKenna

WHEN a new material becomes available to industry, it is useful to describe its properties as a guide to its most effective application; and when the new material may be produced in compositions having a series of graded properties, tests to select the combination of properties best adapted for various uses are helpful. The class of materials to be considered in this paper are hard tool materials produced by processes of powder metallurgy from hard carbide constituents and various matrices of iron, nickel or cobalt, or alloys of them with tungsten, or tungsten and carbon. The customary use of carbide hard alloys is for metal-cutting tools; although wire-drawing dies, lathe centers, follow rests, grinding rests, burnishers, rolls, extrusion dies, measuring gauges and micrometers, and a number of other tools are also made with these hard alloys as the essential wear-resisting parts. The properties and tests to be considered are those affecting these uses. In the development of tool materials since the industrial revolution we have had carbon tool steels, Mushet steel, high-speed steels, stellites, and now cemented carbide compositions. For an understanding of the latter category of materials their properties and uses relative to the older and more familiar tool materials will be considered. Hardness has been the property of greatest practical interest in tool materials. The word "hardness" is a generalized term lacking definite¬ness unless the specific test used is described. However, efforts to explain physical properties as a consequence of chemical bond, and distance between atoms in chemical compounds have been illuminating. This seems the most generalized attack on the problem, and is based upon the idea that atoms in a lattice are held together as the square of the valence and inversely as the square of the distance between the atoms. The compounds compared must all be of the same crystalline arrangement. It is interesting to note the values of the figure [V ] a number of

Jan 1, 1938

By Herbert Clark Hoover, Lou Henry Hoover

IN the last book I have explained the methods of delimiting- the meers along each kind of vein, and the duties of mine officials. In this book1 I will in like manner explain the principles of underground mining and the art of surveying. First then, I will proceed to deal with those matters which pertain to the former heading, since both the subject and methodical arrangement require it. And so I will describe first of all the digging of shafts, tunnels, and drifts on venae profundae; next I will discuss the good indications shown by canales2, by the materials which are dug out, and by the rocks ; then I will speak of the tools by which veins and rocks are broken down and excavated ; the method by which fire shatters the hard veins ; and further, of the machines with which water is drawn from the shafts and air is forced into deep shafts and long tunnels, for digging is impeded by the inrush of the former or the failure of the latter ; next I will deal with the two kinds of shafts, and with the making of them and of tunnels ; and finally, I will describe the method of mining venae dilatatae, venae cumulatae, and stringers.

Jan 1, 1950

By Norman Carmichael, John Kiddie

The problem of transportation in the Clifton-Morenci district of Arizona has been one of peculiar difficulty and consequently has been an important factor in the cost of mining and treating the ores produced. From the crude beginning made over 50 years ago, many changes have been necessary to keep pace with the increased output of copper. A heavy-duty haulage system has developed on the original 20-in. track gage to meet the existent metal-mine conditions. Topography The transportation difficulties of this district may be readily appreciated from the relief map shown in Fig. 1. The northern half of the district is high mountainous country and there is a general but irregular drop toward the southern part, where the country, although still rugged, is in reality a great sloping plain. This is cut by numerous ravines from which the waters, in the rainy season, discharge into the channel of the San Francisco River. A chasm, 1000 ft. deep, has been eroded through the center of the district by Chase Creek, which is flanked by high irregular mountain masses, notably Copper Mountain, American Mountain, Coronado Mountain, and Markeen Mountain. The latter rises 2300 ft. above the bed of the creek, The San Francisco River has also cut a deep channel, though it is somewhat broader than Chase Creek. Eagle Creek traverses the extreme southwest portion of the area, where it has carved picturesquely through vast volcanic flows. Faulting has left its mark upon the topography of the district by adding to the irregularities caused by erosion. Strong faults occur at the Coro-

Jan 1, 1924

By Robert F. Calman

OUTLINE FIVE EXAMPLES OF GOLD-LINKED FINANCINGS 1. Financing the Lupin Mine • Sale of Cdn $40.0 million of 12% preferred shares and Cdn $40.0 million of Gold Purchase Warrants @ $595 per ounce. 2. Financing the Copper Range acquisition • Borrowing 100,000 ounces from a Canadian chartered bank @ US$307 for five years. 3. Financing the Round Mountain expansion • Borrowing up to US $80.0 million in dollars, convertible into gold, repayable over five years from a group of North American banks. 4. Financing the Tenneco Precious Metals Division acquisition •Sale of SFr 110.0 million of ten year 3-718% bonds with warrants to buy 132,000 ounces of gold at US $560. 5. On Forward Sales, Puts and Calls • Gold, Silver, Canadian Dollars, Swiss Francs THE FINANCIAL RULES AT ECHO BAY 1. Never bet the company 2. Equity is the primary form of capital for a gold mining company 3. On debt 4. The Yardsticks for Corporate Decisions 5. Financial Community Relationships 6. Dividend Policy No Text Available Tables Follow

Jan 1, 1990

By Basil Prescott

Resume.—The district of Santa Eulalia lies 12 miles to the southeast of the city of Chihuahua, Mexico. The ore deposits occur in a Cretaceous limestone of unknown thickness, overlain by a series of rhyolitic tuffs and flows. The limestone is very gently folded and is cut by several systems of fissures, of which only those with a general north-south strike are pre-mineral and control the deposition. The deposits are of two main types; the earlier silver-bearing iron sulphide type occurs as high-grade tabular bodies resembling veins and as large masses of relatively low-grade ore, The gangue of this type is composed of lime-iron silicates that point toward a close association with an igneous rock mass which has not yet been encountered. In the later silver-lead-zinc type the ore occurs in vertical chimneys and horizontal mantas, principally as oxides, though at a depth of 1,500 ft. some sulphides have been encountered. During oxidation the ore chambers have increased in size owing to the solution of the walls by the sulphuric acid generated in the process, and a substitution has taken place of nearly one-half part by weight of the original constituents of the ore, by newly introduced elements and radicals. Both types are believed to have come from greater depths than those yet reached by mining, and their ultimate source, from a consideration of similar deposits, is believed to be an igneous rock in contact with the limestone at some horizon below. The deposits are believed to have been formed at unusually great depths, as indicated by the proved great vertical range of the silicate minerals coupled with the absence of the igneous rock, and by the practically unchanged character of the silver-lead-zinc ores as far as developed. The volcanic capping is believed to be distinctly later than the economically important ore deposition. Introduction The Santa Eulalia district is situated in the State of Chihuahua, Mexico, and lies about 12 miles southeast of the capital, the city of Chihuahua. (See map, Fig. 1.) The district embraces the Sierra de La

Jan 1, 1915

By Donald W. Gentry

The recently established SME-AIME Education Board has completed its first full year of operation, and its six constituent committees-Accreditation, Career Guidance, Continuing Education, Educational Statistics, and Scholarship-have been extremely active in identifying and initiating programs to serve the educational needs of the Society of Mining Engineers and its members. The Continuing Education Committee-primarily concerned with the needs and problems associated with providing a continuing education program for SME members-is responsible for: (1) determining the need for short course offerings; (2) developing needed courses, along with new means and opportunities of presentation; and (3) scheduling and evaluating course presentation. In response to this charge, the committee has sponsored two short courses at the SME-AIME Fall Meeting in St. Louis and three short courses at the AIME Annual Meeting in Denver. Its major effort, however, has been directed toward the 1978 SME-AIME Fall Meeting to be held in Orlando, Fla., where 18 days of short-course instruction have been scheduled. A portion of these courses will be presented prior to the meeting, with the remainder to be presented in Nassau, Bahamas, immediately following the meeting.

Jan 7, 1978

Members of Fifty Years or More Lawrence Addicks &apos;02 T H Aldrich &apos;98 Walter H Aldridge &apos;89 Eugene Ant. &apos;99 George H Ashley &apos;99 R M Atwater, Jr &apos;97 James B Bailey &apos;00 Samuel Barker, Jr &apos;00 John F Berry &apos;93 Charles A Bohn &apos;93 W S Boyd &apos;02 H C Boynton &apos;01 H A Brassert &apos;99 Arthur C Brinker &apos;01 James F Brophy &apos;01 Davenport Brown &apos;02 Donald C Brown &apos;01 Victor B Buck &apos;98 Frederick Burbidge &apos;87 Frederick P Burrall &apos;97 John Cabot, Jr &apos;99

Jan 1, 1952

By Fred C. Bond

SIX years have passed since the last grindability table was published.1 In that time the list has been increased with many new tests, and the development of the new Third Theory of Comminution2 has made possible the reduction of all results to a consistent work index value. In this tabulation all grindability and crushability test results are given in terms of the work index, with formulas for reversion to the older units if desired. The average values for 57 different classes of materials are listed in Table I. The total number of work index values listed is 1211, and the overall average work index is 14.42.

Jan 3, 1953

By Ray W. Arms

DRY cleaning, or pneumatic separation, is not, strictly speaking, a recent discovery. Among the archives of the Patent Office may be found many patents dating back as far as 1850 which cover early attempts to separate materials of varying specific gravity or of different shape by means of air. Hundreds of patents covering this art have been issued, which may be roughly classified into four general groups, as follows: 1. Stationary devices with pulsating air currents. The separating surface is usually riffled and air is supplied by bellows or compressors. This group also includes air jigs, which have been used rather extensively. 2. Stationary devices with continuous air currents. These submitted the material to a continuous current of air, either horizontal or vertical. Chaff is blown from wheat by such a device. 3. Reciprocating or vibrating devices with pulsating air. A small group in which the pulsating air is supplied by bellows and some motion provided in the separating surface to move the stratified material to various discharge points. 4. Reciprocating or vibrating devices with continuous air supply. This is by far the most important group and all recent developments have been along this line. All of the above groups involve the stratification of material by air and include none of the dry methods that use other principles, such as coefficient of friction, magnetism, etc. Air Stratification In all of the above groups of air separating devices, the same phenomena are found as exist in water concentrators; that is, free settling will be found in some and hindered settling in others, with a complex action on the reciprocating tables similar to the wet tables. The experimental value of the settling ratios of particles in air has never been determined but, following the formulas given in Richards&apos;

Jan 1, 1924

Jan 1, 1923