Search Documents

Jan 1, 1895

In cooperation with the United States Bureau of Mines and the Idaho Bureau of Mines and Geology, the University of Idaho offers in the School of Mines a number of fellowships. These fellowships are open to college graduates who have had good training in mining, metallurgy, or chemistry, and who are qualified to undertake research work. The income of each fellowship is $720 a year for the 12 mo. beginning July 1, 1919. Fellows will register as students in the University of Idaho and become candidates for the degree of Master of Science in Mining or Metallurgy (unless this or an equivalent degree has been earned). Their class work-will he directed by the heads of the departments of instruction, but the greater portion of their time will be spent in research work under the direction of the Bureau of Mines staff resident at the University. The purpose f this work is to undertake the solution of definite problems confronting the mining and metallurgical industries of the State of Idaho. For 1919-20 the following subjects are being considered: 1. Flotation-with especial reference to differential separation of various minerals. 2. Availability of western wood oils for flotation purposes. 3. Treatment of the complex gold-silver ores of southern Idaho. 4. Ore-dressing problems. 5. Mining problems. Applications, with certified copy of collegiate record, statement of professional experience, and names and address of three references, should be addressed to The Dean. School of Mines. Moscow Idaho_

Jan 6, 1919

By Herbert Clark Hoover, Lou Henry Hoover

QUESTIONS of assaying were explained in the last Book, and I have now come to a greater task, that is, to the description of how we extract the metals. First of all I will explain the method of preparing the ore1 ; for since Nature usually creates metals in an impure state, mixed with earth, stones, and solidified juices, it is necessary to separate most of these impurities from the ores as far as can be, before they are smelted, and therefore I will now describe the methods by which the ores are sorted, broken with hammers, burnt, crushed with stamps, ground into powder, sifted, washed, roasted, and calcineda.

Jan 1, 1950

By Arthur Bell

(San Francisco Meeting, September, 1915) . PRIOR to 1908 the oil production in the State of California, had been almost entirely a heavy fuel, oil, with a high flash point, hut changed within a-short period to a large percentage of refining oil with a low flash, by reason of the coming in of the Santa Maria field, the Midway field, and the increased production of the Fullerton field. This is clearly shown in the following tabulation of California's production: Year Barrels . Below -20° Be, Above 20° Be,, Per Cent_ Per Cent. 1905 48,307,000 90 10 1910 77,698,000 SO 20 1912 90,075,000 6o 31 1914 10:3,600,000 47 53 The bringing in of these high percentage's of light oil with their dangerous low flash and the increasing demand for the refined products necessitated the devising of some cheap and efficient means of quickly separating the lighter elements either in the field or at the main distributing points; also it became necessary to remove the excessive percentage of water which many of the light oils carried in emulsion.

Jan 9, 1915

By Robert A. Rapp, Ronald L. Pastorek

Solid-state electrochemical measurements by three alternative experimental procedures were made with the cell FeO, Fe3O4 |Zro.85Cao.15O1.85 |Cu| Zr0.85CaO.15O1.85 | FeO, Fe304 to establish the solubility and diffusivity of oxygen in solid copper in the temperature range 800" to 1030°C. The solubility of oxygen in solid copper and the diflusivity of oxygen in solid copper Dgu = 1.7 X 10-2 exp(-16,000/RT) Cm2/sec were determined and confirmed in alternative experiments. The enthalpy of solution of oxygen in solid copper equals —10,000 cal per mole; the partial excess entropy of the oxygen atoms in the Cu-O dilute solution is approximately the same as that found for interstitial atoms in other metals. The diffusivity of oxygen in solid copper is consistent with that expected for an interstitial atom. RELIABLE values for the saturation solubility N(s) and diffusivity DO of oxygen in solid copper have not been unambiguously established in the literature. Following three early determinations by others,1"3 Rhines and Mathewson4 reported that the solubility of oxygen in solid copper increased from 0.007 at. pct 0 at 600°C to about 0.015 pct at 1050°C. Phillips and skinner,, using essentiially the same analytical procedure, reported that the solid solubility increases from 0.0018 at. pct 0 at 550°C to about 0.0075 pct at 1050OC. The only previous value for the diffusivity of oxygen in solid copper was reported by Ransley.6 Ransley deoxidized Cu-Cu2O alloys in an atmosphere of carbon monoxide gas to yield a solubility-diffusivity product. He used the solubility data of Rhines and Mathewson to calculate the diffusivity values. Another method for obtaining the solubility-diffusivity product (N(s) DO) is by measuring the widths of internal-oxidation zones in copper alloys as reported by Verfurth and Rapp.7 However, the calculated N(S)Do products depend upon the alloy content of the specimen, so that the internal oxidation of copper alloys does not follow ideal internal oxidation kinetics. As a result, unequivocal values for the N(s) DO product were not obtained by this procedure. A solid-state coulometric titration technique similar to that employed in this work was introduced by C. Wagner8 to study the dependence on silver activity of the Ag/S ratio in silver sulfide in the temperature range of 160" to 300°C. Similar experiments have been carried out by C. Wagner and co-workers9-11 to study the stoichiometry range of silver and copper tellurides, cuprous sulfide, and cuprous selenide. Numerous authors have carried out electrochemical measurements with a solid oxygen-ion-conducting electrolyte to determine the solubility and/or diffusivity of dissolved oxygen in several liquid metals.12-l6 Rickert and Steiner17,18 have used solid-state electrochemical measurements to determine the diffusivity of oxygen in solid silver from 760" to 900°C. Two different cell geometries were used. In the cell of linear geometry Fe, FeO | ZrO2 + (CaO) | Ag + [0 (dissolved)] [1] oxygen diffused from the interior of the silver electrode to the silver/electrolyte interface where the oxygen activity had been lowered from a fixed initial value to practically zero by the application of voltage to the cell. The diffusivity of oxygen in solid silver was determined from the solution of the diffusion equation and the time dependence of the cell current. However, this determination of the diffusion coefficient depended upon a knowledge of the solubility of oxygen in solid silver. A cylindrical geometry was used for the cell Pt, O2(Po2 = 0.21 atm) | ZrO2 + (CaO) | Ag + [0 (dissolved)] [II] which also allowed the diffusivity of oxygen in solid silver to be determined. These values were in agreement with other available data.l9 Recently, Raleigh20,21 used a method involving the measurement of diffusion-limited currents in a cell involving the AgBr solid electrolyte to determine the diffusion coefficient of silver in Ag-Au alloys at 400°C. Diffusivity values on the order of l0-14 sq cm per sec were measured in the alloy composition range 10 to 60 at. pct Ag in a single experiment. From numerous electrical conductivity and galvanic cell measurements,9'22"26 the solid solution Zr0.85 Ca0.15 O1.85 has been established as an electrolyte with predominant oxygen ion conduction over a wide range of intermediate and high oxygen activities. For interrelating the thermodynamics and the kinetics of the dissolution of oxygen in solid copper in this investigation, a galvanic cell was constructed with FeO-Fe3O4 as the reversible reference electrode, the Zr0.85Ca0.15 O1.85 electrolyte, and a pure copper specimen under-saturated in oxygen as the other electrode. THEORETICAL ANALYSIS Three variations of a high-temperature electrochemical technique were used in this study to provide two determinations each of the solubility and diffusivity

Jan 1, 1970

By Leon O. Hart

The nickel-chromium alloys of importance are those containing iron and those free from iron. The most important alloys containing iron, with regard to high tonnage, are the nickel-chromium steels. Straight nickel steel was introduced about the year 1889, but it was not until 1895, when it was found that the addition of chromium greatly increased the strength and resistance to shock, that nickel-chromium steels came into use. The three types of nickel-chromium steels developed at this time were: Type 1, containing 3.,50 per cent. nickel and 1.50 per cent. chromium; type 2, containing 2.00 per cent. nickel and 1.00 per cent. chromium; and type 3, containing 1.50 per cent. nickel and 0.50 per cent. chromium.

Jan 1, 1921

By Alfred F. Brainerd

A pure white sand, in a large deposit, favorably located with regard to water and railroad transportation, is very desirable for metallurgical and manufacturing purposes. Such a deposit occurs

Jan 1, 1886

By Ernest Klepetko

A NOTABLE amount of fossil resin exists in many of the bituminous coal beds of Utah. The upper part of these show a marked concentration of resin, which occurs primarily in the fracture seams. In general, these seams are less than 1/8 in. thick, but it is not uncommon to find coal with areas as thick as 3/8inches. The resin is of the hard kauri variety, with coloration varying from deep blood red to lemon yellow and almost colorless. There is also an almost black variety, which is not readily soluble in the same solvents as the lighter colored resins. These resins are valuable for many industrial purposes. When refined, they are suitable for uses similar to those for which lac resins are usually employed. They are particularly desirable for preparing dielectric varnishes. They are also desirable in preparing printing inks, waterproofing agents, special synthetic rubbers and rubber cements. They are especially suitable as an admixture in synthetic rubbers and cements, as they supply the essential tackiness the synthetics lack. The following chemical trade characteristics have been found by Inter-Chemical Co. research chemists in the refined resins: [Specific gravity (melted) 1.03 -1. o6 Acid number6-8 Softening point, mercury method 160 -165°C Iodine value (Wijs)140-1.50 Refractive index1.544 Color (Hellige, 25 pct toluol) ...14 Molecular weight, average732 Purity, 99 + pct pure hydrocar Bon] "Unaffected by alkalies and resistant to one hour fusion with solid potassium hydroxide. Completely soluble in aliphatic and aromatic hydrocarbons. Insoluble in alcohols, ethyl acetate and other commonly used alcohols and esters. Compatible with natural and synthetic rubbers, chlorinated and cyclized rubbers, waxes, vegetable oils, mineral oils, rosin, ester gum, phenolic and modified phenolic resins and other natural and synthetic resins of like solvent solubility. The recovery and refining of these fossil resins has been the subject of much research work and has intrigued many investigators. Broadly speaking, the problem involves separation of the resin from the coal into a very high-grade concentrate, and subsequent treatment of this concentrate to produce an acceptable refined resin for its various usages. Obviously it is also desirable to recover the residual coal without excessive size degradation. The late W. D. Green, concentration engineer for Combined Metals Reduction Co., obtained U. S. Patent No. 1773997 for the recovery of resin from coal through

Jan 1, 1947

Edmund Gybbon SpilsbURy, mining and metallurgical engineer of international reputation, died suddenly of heart failure on May 28, 1920, in the New York Eye and Ear Infirmary, following an operation for cataract, which had been successfully performed a few days before. Mr. Spilsbury was one of the early members of the American Institute of Mining Engineers, which he joined in 1873. During all this time he contributed freely of his time and ability. He was manager of the Institute from 1885 to 1887, vice-president, 1893 and 1894, and president in 1896. He was also a member of the Engineers Club, of which he was president in 1916 and 1917, American Society of Civil Engineers, American Society of Mechanical Engineers, Institution of Mining and Metallurgy, Mining and Metallurgical Society of America, American Electrochemical Society and the Rocky Mountain Club of New York. He was a trustee of the United Engineering Society from 1916 to his death; a member of United Engineering Society Library Board from its organization in 1913 until his death, being its chairman from 1918 to January, 1920; a trustee of Engineering Foundation Board from 1916 until his death; and member of the John Fritz Medal Board of Award. He was also a member of the Division of Engineering of the National Research Council. Born in London, England, in 1845, Mr. Spilsbury went to Liege, Belgium, at an early age, where he received his preliminary education. For his technical education he attended the University of Louvain, Belgium, graduating in 1862, and later he took a practical course at Clausthal, Germany. In 1864 he became assistant engineer for the Eschweiler Zinc Co., of Stolberg, one of the largest miners and smelters of lead and zinc in the world at that time, and the next year he took charge of that company's mines and works on the Island of Sardinia. From Sardinia he went to the Atlas Mountains in Morocco. In 1867 he entered the service of McClean & Stilman, of London, and had charge of the construction of the iron gates for the Surrey Commercial Docks. In 1868 he was designing engineer with J. Casper Harkort, and had charge of most of the detail work of the Keulenberg Bridge in Holland, the Danube Bridge in Vienna, and the Rhine Bridge at Düsseldorf. In 1870 Mr. Spilsbury came to the United States to investigate the lead and zinc resources for the Austro-Belgian Metallurgical Co. After spending two years in this work, he resigned in order to practice in the United States, and he was the first to introduce the Harz system of ore

Jan 1, 1922

By Kwong Yung Kwang

This mine, which is sometimes called Tong colliery, from its director, Tong King Sing, is about 80 miles northeast of Tientsin (see map, Fig. 1). Fig. 2 shows a vertical transverse section through the coal-beds. These beds have a dip to the south of about 45' and are interstratified with sandstone, shale, indurated clay and fire-clay. Of the

Jan 1, 1888

By Robert Ammon

THE milling practice at Mascot, at present, consists of dry crushing to 5/8 in., jigging, fine grinding, and flotation. The ore arrives at the mill from two mines, No. 1 mine shaft being located in the mill proper, and No. 2 mine shaft being situated about 2000 ft. east of the mill. No. 2 mine is served by a coarse-crushing plant and aerial tramway to the mill bins. In jigging the No. 2 mine ore, 50 per cent. of the mill feed is rejected by the jigs as a jig tailing ranging from 5/8 in. to 10 mesh; the balance of this ore, after removing a jig concentrate, is ground to flotation feed. In jigging No. 1 mine ore, approximately 80 per. cent. of the mill feed is rejected as a coarse jig tailing, and the balance is ground to flotation feed without the removal of a jig concentrate. The difference in the treatment is due to the fact that No. 2 mine ore carries a higher content of zinc than that from No. 1 mine. Of the total concentrates produced, 30 per cent. are made on jigs and 70 per cent. by flotation. At present, 1350 tons of No. 2 ore and 800 tons of No. 1 ore are treated each 24 hours. The recoveries for a typical week are as follows: Heads 3.55 Jig concentrates 61.30 Jig tails 0.80 Flotation concentrates 60.60 Flotation tails 0.09 Extraction 86.50 The associated minerals are a straw-colored sphalerite, dolomite, calcite, pyrite, quartz, and a small amount of greenockite, which occurs as a stain and sometimes small crystals along with sphalerite, but is comparatively rare. Pyrite is present in small quantities, usually less than 0.5 per cent.; quartz occurs in bands a few inches thick. A complete analysis of the ore is as follows:

Jan 9, 1924

By A. T. Miesch, L. B. Riley

An error occurred in the preparation of Fig. 3, p. 249, of Basic Statistical Measures Used in Geo-chemical Investigations of Colorado Plateau Uranium Deposits. This figure shows the relation of the arithmetic mean: geometric mean ratio to the geometric deviation. Curves for the cases where n, the number of samples, is 100, 10, and 5 are too high with respect to the ordinate. The error is negligible at low geometric deviations, but becomes increasingly greater wi,th higher values of geometric deviation. Arithmetric mean values in Table I1 are not effected by the errors in Fig. 3. The authors will endeavor to supply copies of the revised curves on request; write to: A. T. Miesch, Geologist, Branch of Radioactive Materials, U.S. Geological Survey, Bldg. 25, Federal Center, Denver 25, Colo.

Jan 1, 1962

By Lester Strauss

The fact that the loss of silver in the slag of the smeltingprocess increases with the amount of silica in the furnacecharge, was probably the ground of a general opinion that the silver is present in the slag as a silicate. Dr. Iles, in his inter-

Jan 1, 1901

By H. Y. Hunsicker

A graphic method has been devised for three-di-mensional analysis of hot deformation and for correlating the amount and directionality of the deformation with resulting directional properties. Deformation is evaluated in terms of dimensional change ratios referred to three orthogonal axes. Since all combinations of the three ratios can be represented in a triangular coordinate field with logarithmic scales, a two-dimensional chart of extent of deformation and degree of asymetry is possible. The entire gamut of shape changes from upsetting through flat-rolling to rod-rolling is accommodated. The resulting coordinate system is a base upon which can be represented the properties of the wrought products measured in the directions of the axes employed fir evaluating the deformation. When property data are available for many types and amounts of deformation, a three-dimensional figure can be constructed, and the projection of this figure is referred to as a ''3d'' chart. Experience in using such charts to plan fabricating operations for a variety of thick-section forged and rolled products of heat-treated aluminum alloys has verified its practical value for optimizing directionality relationships. MechANICAL anisotropy of thick section products of heat-treatable aluminum alloys is recognized by producers and users of these products, and the extent of the directional differences is apparent in property tabulations included in handbooks, standards, and specifications.' Attention has also been directed to the existence of important directional differences in the resistance of these products to stress-corrosion cracking. Metallurgical structure factors responsible for these directional differences include, among other possibilities, shape and alignment of grains, voids and nonmetallic inclusions (when present), volume fraction and spatial distribution of secondary phase particles and solid-state precipitates, crystal-lographic textures, and Bauschinger effect. The contributions of the individual factors vary with alloy composition, heat-treated temper, type of working process (forging, rolling, extrusion), and the amount and directional nature of the deformation. In general, the cast ingot used as the starting material for producing these wrought products exhibits only a modest degree of directionality. A monotonic and continuous transition from this nearly isotropic state with progressive hot deformation would appear probable, assuming that the working temperature is sufficiently high to cause continuous dynamic recovery. Several years ago a project was undertaken to evaluate the effects of hot deformation and metallurgical structures on the directionality of thick wrought aluminum alloy products, and the method to be described was developed as an analytical tool in this investigation. DIRECTION NOMENCLATURE The nomenclature system adopted by industry for the three mutually perpendicular directions employed in testing aluminum alloy products includes four terms: "longitudinal", "transverse", "long transverse", and "short transverse". These terms are conventionally related to the external geometry of the product but also by implication to the deformation and resulting metallurgical structure. Occasions arise in which through use of unusual fabricating methods, intentional or otherwise, the structure does not have the usual relationship to external geometry or may be very complex because of inhomogeneity of deformation throughout the piece. The longitudinal direction is generally parallel to the primary rolling direction or to the direction of extrusion. In the case of forging, it is parallel to the direction of maximum extension (not maximum "working" or "flow", as frequently stated). The term transverse is applied to any direction perpendicular to the longitudinal direction in a product having symmetry about the longitudinal axis, and generally, although not always, the deformation to produce these forms is nearly symmetrical in the transverse plane. This term then may be applied to a round, square, hexagon, or other polygonal, symmetrical shape produced by extrusion or rolling or by forging, if produced by a simple, symmetrical drawing procedure. The type of microstructure generally associated

Jan 1, 1970

Jan 1, 1921

Jan 1, 1935

Map

Jan 1, 1941

By B. E. Fernow

MINING interests in the Western mountains are very seriously affected by the danger to property and life from destructive snowslides and avalanches. This is a danger which the miner has largely brought upon himself by an improvident stripping of the timber from the mountain slopes, and, therefore, he might be expected to take an interest in the reforestation of the areas thus devastated. A canvass was lately undertaken by the writer to ascertain approximately the extent of the damage suffered from this source, but the difficulty of obtaining reliable data has proved too great to permit, as yet, even an approximation. So much, however, is certain : that the loss of life is considerable, and that much property is destroyed almost every winter. True, neither the number of avalanches, nor their destructiveness, nor the amount of loss compares with what Switzerland experiences. This is due not only to the greater precipitousness of the Alps and to different climatic conditions, but also to the fact that in Switzerland a larger number of settlements is exposed to these dangers. A very complete and interesting official report on the very numerous and destructive avalanches occurring in Switzerland during the season of 1887-1888 has just been published as a contribution to the inquiry, whether and how these dangers can be averted. Peculiar weather-conditions, in addition to heavy falls of snow, were the reasons for the frequency of the phenomenon during that winter. This report records 1094 avalauches, by which 850 houses were destroyed or severely damaged; 84 persons and 752 cattle were buried; traffic on railroads and on highways was greatly interrupted, and the damage to personal property alone was valued at over $100,000. One of these snow-masses covered about half an acre, with a cone 250 feet in height. During the same year in Tyrol the number of avalanches was 3647. Of these 1355 run over permanent beds; that is, they recur annually, so that they are

Jan 1, 1890

By Elmer R. Kaiser

COMBUSTION of coal and transfer of heat from flames and gases to boiler surfaces continue to be of great interest to engineers here and abroad. Numerous investigations have been in progress to improve furnace and boiler performance and economy. The importance of better understanding of the processes and opportunities for improvement is apparent when it is remembered that heat from at least 500 million tons of coal a year the world over is being transferred to boiler water at efficiencies ranging mostly between 50 and 90 pct. Even slight gains in efficiency, economy, and labor saving become very significant when multiplied by the enormous quantity of fuel consumed. Also the competitive position of the large coal, oil, and gas industries in satisfying the fuel consumers is greatly affected by the achievements made through technical progress with each fuel. This paper is part of a continuing activity of Bituminous Coal Research, Inc., to extend the knowledge of coal utilization for steam generation and to seek promising directions for future research and development in cooperation with others. Particularly in the latter regard, numerous interviews were held during the last three years to seek the experience and advice of boiler and combustion-equipment manufacturers, electric-utility executives, and fuel engineers. A wealth of published information was also reviewed, which together with the interviews pointed to the advisability of further work on ash and sulphur control. For the present purpose a number of factors important to efficient heat liberation and recovery have been grouped as follows: 1—combustion, temperatures, and rates of heat liberation; 2—radiation, convection, and furnace and boiler configuration; 3—sponge ash, slag, and hard-bonded deposits; 4— low-temperature deposits and corrosion (cooling flue gas below dew point and air-pollution control); 5—the limitations of coal cleaning and boiler size and cost as related to fuel characteristics; 6—future possibilities and conclusions. The development of combustion apparatus for power boilers is progressing at a lively pace. There has been no letup in improvements in design of pulverized-coal-fired boilers, and there is a strong trend at present toward improving dry-bottom units. Spreader stokers with overfire jets and dust collectors as standard equipment are gaining favor. Less than 10 years in commercial use, cyclone burners are going into numerous installations here' and abroad.' Underfeed and traveling-grate stokers have long since been developed for heavy-duty operation, yet new developments in overfire jets and humidification of air blast have improved their performance. A water-cooled vibrating-grate stoker of German origin is being introduced into the United States and Canada." The primary objectives of an ideal coal combustion device are: capacity to burn the variety and sizes of coals likely to be economically available during the life of the unit; capacity to burn the coals automatically for a wide load range and rapid load fluctuations and to burn the coals completely to CO2, H2O, and SO2, which means without smoke and cinders, or carbon in the refuse; capacity to control and discharge all the ash in final granular form without ash adhesion to walls or tubes, and without flue dust; minimum furnace volume; minimum labor and maintenance; low initial and operating cost. Regardless of the method of burning, the gaseous products of coal combustion are N2, CO2, O2, H20, and SO?. By way of illustration, the coal analyses in Table I is assumed from an installation described by E. McCarthy.' When coal is burned with 20 pct excess air (theoretical air, 9.23 lb per lb of coal), the quantities of combustion gas shown in Table II are produced. In addition, the gases carry particles of fly ash, unconsumed cinders, soot particles, and small but significant amounts of vaporized oxides and sulphates of sodium, potassium, lithium, phosghorous, iron, and other metals. In recent years, germanium, one of the rare metals found in coal, has been shown to oxidize and vaporize at combustion temperatures and to be concentrated by reconden-sation at lower temperatures." Pulverized coal and cyclone flames" have peak temperatures of 3000' to 3500°F. Temperatures in fuel beds of large underfeed stokers reach maxima of 3000°F, sufficient to fuse almost any ash and to volatilize some of it. These peak temperatures are above the optimum necessary for rapid combustion, but they hasten heat transfer for ignition as well as boiler heat absorption. Furnace and gas temperatures increase with combustion air preheat. Low excess air has the same effect. Fine coal pulverization and highly turbulent combustion shorten the distance for fuel burnout, increase flame temperature, and speed up heat transfer. Rates of combustion of pulverized coal exceeding 200,000 Btu per cu ft per hr have been demonstrated in atmospheric gas-turbine combusters,

Jan 1, 1955

By Claudio Barsotti, Leonard C. Kitchener

INTRODUCTION The major mining operations of the Ontario Division of Inco Metals Company are located in the Sudbury Basin. Around the rim of this geo- logical formation and within thirty miles of the City of Sudbury are located eleven under- ground mines of the Company, two of which are on standby. In addition, there is one mine in Northwestern Ontario at Shebandowan, 1127 Km (700 miles) northwest of Sudbury. In 1980 ore production totalled 10.6 x 10 mt (11.7 million tons) from underground and open pit operations. Underground mining methods include blasthole, vertical retreat, sublevel caving, cut-and-fill and undercut-and-fill. Inco reduction operations in the Sudbury area include two concentrators, one smelter, one iron ore recovery plant, a copper refinery a nickel refinery and a high purity plate rolling mill. As well, an electrolytic nickel refinery is located on Lake Erie at Port Colborne, near Niagara Falls. In the Sudbury District, Inco employees total 14,278 of whom 6,490 are directly employed in the mining and milling operations. I T H DRILLING Background - The use of long blastholes in underground operations at Inco mines in the Sudbury district started more than 30 years ago at the Levack Mine. At that time, diamond drills were used to mine ore by open stoping and for pillar recovery. By the 1950's the concept had been extended to all mines. The heavy percussion drill was also developed by this time and led to the acceptance of the 11.43 cm (4% in.) piston diameter drifter for bar and arm and fan drill applications. The use however, of the nominal 5.08 cm (2 in.) diameter blastholes drilled radially from the level or sublevel causes overdrilling at the periphery. As well, the smaller holes are subject to hole deviation, are difficult to drill beyond 38.1 m (125 ft.) and require the need for several drilling horizons or sublevels. The need to improve blasthole stoping techniques and our experience with large diameter blastholes in open pit mining led to the trial of an I T H drill in 1962. The test was unsuccessful however, since button bits were not available at the time and the tungsten carbide cross bit experienced short life, gauge loss, and caused hole deviation and poor penetration rates. The successful application of the raise borer beginning in 1964 and the ability to drill 20.32 cm (8 in.) to 27.94 cm (11 in.) diameter pilot holes led to the development of smaller, more portable, rotary drills for blasthole mining. As a result, a mining method based on the use of 20 cm (7 718 in.) diameter, 60.1 m (200 ft.) long rotary blastholes was developed and tested successfully at our C.C.North Mine. Between 1972, when the method was first tested, and 1973 over 4572 m (15000 ft.) of large holes were drilled with rotary drills in the recovery of 175,960 mt (194000 tons) of primary stoping and pillar remnants. A new mining method was developed that made use of this large hole drilling equipment. Instead of longhole carbide drilling by bar-and-arm or fan drill set-ups at sublevels, the large diameter holes were drilled full stope height from the top sill, which substantially reduced development, drilling time and improved fragmentation. These drills however, were difficult to move and set-up, and had a high maintenance cost and low productivity. The capital outlay and extensive technical development required to improve these drills and reduce the high drilling costs however, was economically unattractive. New development in drills and button bits INTRODUCTION The major mining operations of the Ontario Division of Inco Metals Company are located in the Sudbury Basin. Around the rim of this geo- logical formation and within thirty miles of the City of Sudbury are located eleven under- ground mines of the Company, two of which are on standby. In addition, there is one mine in Northwestern Ontario at Shebandowan, 1127 Km (700 miles) northwest of Sudbury. In 1980 ore production totalled 10.6 x 10 mt (11.7 million tons) from underground and open pit operations. Underground mining methods include blasthole, vertical retreat, sublevel caving, cut-and-fill and undercut-and-fill. Inco reduction operations in the Sudbury area include two concentrators, one smelter, one iron ore recovery plant, a copper refinery a nickel refinery and a high purity plate rolling mill. As well, an electrolytic nickel refinery is located on Lake Erie at Port Colborne, near Niagara Falls. In the Sudbury District, Inco employees total 14,278 of whom 6,490 are directly employed in the mining and milling operations. I T H DRILLING Background - The use of long blastholes in underground operations at Inco mines in the Sudbury district started more than 30 years ago at the Levack Mine. At that time, diamond drills were used to mine ore by open stoping and for pillar recovery. By the 1950's the concept had been extended to all mines. The heavy percussion drill was also developed by this time and led to the acceptance of the 11.43 cm (4% in.) piston diameter drifter for bar and arm and fan drill applications. The use however, of the nominal 5.08 cm (2 in.) diameter blastholes drilled radially from the level or sublevel causes overdrilling at the periphery. As well, the smaller holes are subject to hole deviation, are difficult to drill beyond 38.1 m (125 ft.) and require the need for several drilling horizons or sublevels. The need to improve blasthole stoping techniques and our experience with large diameter blastholes in open pit mining led to the trial of an I T H drill in 1962. The test was unsuccessful however, since button bits were not available at the time and the tungsten carbide cross bit experienced short life, gauge loss, and caused hole deviation and poor penetration rates. The successful application of the raise borer beginning in 1964 and the ability to drill 20.32 cm (8 in.) to 27.94 cm (11 in.) diameter pilot holes led to the development of smaller, more portable, rotary drills for blasthole mining. As a result, a mining method based on the use of 20 cm (7 718 in.) diameter, 60.1 m (200 ft.) long rotary blastholes was developed and tested successfully at our C.C.North Mine. Between 1972, when the method was first tested, and 1973 over 4572 m (15000 ft.) of large holes were drilled with rotary drills in the recovery of 175,960 mt (194000 tons) of primary stoping and pillar remnants. A new mining method was developed that made use of this large hole drilling equipment. Instead of longhole carbide drilling by bar-and-arm or fan drill set-ups at sublevels, the large diameter holes were drilled full stope height from the top sill, which substantially reduced development, drilling time and improved fragmentation. These drills however, were difficult to move and set-up, and had a high maintenance cost and low productivity. The capital outlay and extensive technical development required to improve these drills and reduce the high drilling costs however, was economically unattractive. New development in drills and button bits

Jan 1, 1981