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By E. Howard Lambert

"Operating costs of mining plants are increasing due to the increased cost of labour, materials and fuels. Labour and materials costs are factors not readily controlled. However, the use of energy from fuels may be controlled by plant operations. This paper describes the fossil fuels, their expected rate of depletion and their costs. The paper considers methods which may be used to provide an efficient use of energy from fuels. It includes an outline of obtaining energy, as heat, from mine milling operations (air compression) and obtaining the maximum use of energy from fuels used to generate electricity."

Jan 1, 1973

By M Saghaeian, M Zare, V Sheikhzadeh, R Hejazi

High-Pressure Grinding Roll (HPGR) is one of the efficient methods for increasing the specific surface area (SSA) of iron ore concentrate for pellet feed production. HPGR grinding mechanism implies that material should compressed between the two rolls, therefore layer of material must be able to resist required pressure for achieving suitable grinding conditions. In this study, by doing SSA increasing tests with pilot HPGR, the effects of silica reduction on SSA increasing results were investigated. For this purpose, HPGR tests were performed on an Iranian magnetite concentrate before and after reverse flotation silica reduction tests. Based on the laboratory test results, silicates have been concentrated in two fraction sizes of the sample comprises coarser than 150 microns in form of quartz and finer than 7 microns in form of iron silicates. These silicates have been effected on reduction of concentrate bed pressure resistance by creating a pasty and sticky mud. In this condition, HPGR cannot work properly and operation results are not acceptable. According to flotation silica reduction tests, with 90 per cent weight recovery, concentrate Fe grade is increased from 67.8 per cent to 69.5 per cent and SiO2 content is reduced from 1.98 per cent to 0.9 per cent and especially for lower than 7 microns fraction size, as a critical fraction, SiO2 content decreased from 4.45 per cent to 2.35 per cent. HPGR tests were performed on 8 per cent moisture in 4 N/mm2 specific force and according to the results after silica reduction HPGR operation conditions are optimised. Results showed that the working gap increased from 7 to 10.5 mm and specific throughput of material raised from 180 ts/hm3 to 250 ts/hm3 , and SSA increased by 300 cm2 /gr in a single pass.

Aug 24, 2022

By C. J. Newman, K. Molnar, A. G. Storey, G. Macfarlane

"The Kidd Creek copper smelter started operation in June 1981 using the Mitsubishi Continuous Smelting Process. A steady increase in plant production rates has been demonstrated, and the annual tonnage of concentrate smelted is now double the original design rate. This paper summarizes recent modifications made to increase concentrate feed rates, increase on-line time, reduce copper losses and control the impurity level in anode copper. It includes improvements made to furnace design, improvements to reduce downtime f or boiler cleaning, and improvements made to the acid plant to allow handling of increased gas flowrates and higher gas strengths while maintaining low acid plant emission rates. IntroductionThe Kidd Creek Division of Fal conbridge Limited operates a base-metal mining and metallurgical complex, located in Timmins, Ontario, which includes an underground mine, a 13 500 tonne/day concentrator, a 130000 tonne/year zinc plant and a copper smelter and refinery, The copper smelter and refinery were commissioned in 1981, with an installed capacity of 59 000 tonnes/ year of cathode. The smelter, utilizing the continuous smelting technology of the Mitsubishi Process, has subsequently been expanded in production capacity, and in 1991 produced 113 500 tonnes of blister copper The capacity of the refinery, which uses Onahama No. 3 tankhouse technology, has been increased to 96 000 tonnes/year of cathode. The capacity increase at the smelter has been realized through the input of additional oxygen to both the smelting and converting furnaces, without increasing the process off-gas flowrate through the associated waste heat boilers.In this paper, a brief review of smelter operation and modifications in the period 1982 to 1987 is presented, together with a more detailed discussion of operation during 1988 to 1991, and a discussion of future planned improvements."

Jan 1, 1992

By Johann F. Kerl

Autogenous batch grinding tests were performed in laboratory-scale tumbling mills with magnetite, limestone, and sandstone pebbles. The influence of pebble size, feed size, mill speed and loading, and grinding time on the fineness of grinding was investigated. Comparisons were made with the results from ball mill grinding experiments.

Jan 1, 1972

By Jack Mantel

The goal of this 42-month contract was to increase safety in low-seam underground coal mines through development and in-mine evaluation of a temporary roof support system for roof drills and floor-riding operator compartments for a loader and shuttle car. The program was performed in three phases. During Phase I, state-of-the-art canopy technology was investigated, and preliminary design and mock-up evaluations were performed for temporary roof supports for single-and dual-boom bolters and for transverse-mounted floor-riding canopies for a shuttle car and coal loading machine. The shuttle car and loader canopies were approved for further development, and the design, fabrication, testing, and certification were completed in Phase II. In Phase III, the Bureau of Mines furnished an FMC 6L shuttle car fur use in the evaluation of the canopy for 45 shifts. The shuttle car canopy was evaluated at Virginia Crews Coal Company in West Virginia. Efforts to secure an evaluation site for the loader canopy were unsuccessful. The loader canopy was shipped to Bruceton for possible future evaluation.

Jan 1, 1985

By Stanley Reichert

The manganese deposits of the Embree Iron Co., Embreeville, Tenn., are thought to be fairly typical and representative of the East Tennessee type of deposit, and so to warrent rather detailed description. The methods used by the Embree Iron Co. for prospecting and mining, and to a lesser extent for milling; should therefore be applicable to other East Tennessee manganese deposits, as yet' undeveloped. Early History and Discovery of Manganese Brown iron ore (limonite) was mined by the Embree Iron Co. at various times from 1890 to 1910. The early method was simply pick-and-shovel mining in open pits. Later hydraulic giants were used and sluice lines carried the ore down the mountain slopes to log washers.. During this phase of mining, manganese ore was discovered under the iron ore in some of the pits. In other areas oxidized zinc ore was found under the iron. It thus happened that the valuable zinc deposits were discovered in 1914. During the World War period, from 1914 to 1918, there was sporadic prospecting for manganese ore among the abandoned iron workings, but the main activity then centered around the recently discovered lead and zinc deposits. It was not until 1934 that manganese mining began in earnest, under the supervision of R. D. Pritchett, Mine Superintendent. Geology of the Manganese Deposits United States Geological Survey Folios 151 (Roan Mountain) and 118 (Greeneville show that Bumpass Cove is a synclinal structure thrust faulted along the southeast flank, but with normal sequence of strata along the northwest flank. Fig, l. shows the areal geology of Bumpass Cove as taken from the folios superposed on the U.S.G.S. -T.V.A. 1/24,000 topographic maps of the Erwin and Telford 7 ½ minute sheets. The manganese mines occur near the contact of the unfaulted Shady dolomite and the Erwin quartzite. This contact zone is deeply weathered, with overburden averaging 40 to 60 ft. thick. The material overlying' the bedrock along this normal contact is a very tough, plastic clay, termed "buckfat" or "ocher" by the miners. It is not a true ocher, however, in the sense of having commercial value. The manganese deposits occur along this "ocher" band. Fig. 1 also shows how the manganese deposits occur along the broad topographic terrace between the 2100 and 2200-ft. contour lines. This terrace lies at the foot the Erwin quartz ridge. Apparently it is the topographic is expression of the deeply weathered zone along the Shady-Erwin contact.

Jan 1, 1941

By Stephen Utter

Stresses induced by block-caving mining were estimated from in-place measurements of strain or deformation in rock and concrete around mine openings. The four types of gages used for measurements in the Climax Molybdenum mine during 1959-61 were Whittemore gage, Carlson strain meter,2 Valore strain cell, and Climax extensometer. Gage performance in the laboratory was evaluated by stressing instrumented rock and concrete specimens in a universal testing machine and by comparing measurements taken by the gages and a standard gage. Gage performance in the mine was evaluated by comparing measurements taken during an 18-month test. The Whittemore gage, Carlson strain meter, and the Climax extensometer proved suitable for the investigation; the Valore strain cell, effective in the laboratory tests, gave erratic measurements in the mine.

Jan 1, 1965

By Paul L. Russell

THIS is a progress report of an experiment being undertaken in cooperation with the Bethlehem Steel Corp., the Crucible Steel Co., and the Rock Bit Sales and Service Co., involving heat treatment of the shank ends of drill steel. This experiment is being conducted by the U. S. Bureau of Mines in its experimental mine, Mining Research Branch, Bluemont, Va. The purpose of the experiment is to determine the effect of an increase in the time the steel soaks in the furnace during the hardening heat. It has been thought that increasing this time produces a soft zone below the lugs resulting in a metallurgical notch that causes early failure. Each of the steel companies furnished enough 11/4 - in. straight carbon, hollow, round steel to make up 10 sets of drill steel, in each instance the steel bars were from the same heat. These sets of drill steel, consisting of 2-ft, 4-ft, 6-ft, and 8-ft lengths were fabricated by the Rock Bit Sales and Service Co. Special attention was given to the forging of the steel to produce the best rods possible. The heat treatment of all thread ends was identical and followed the best practice. The heat treatment of the shank ends of five sets of steel from each company produced a soft zone 2 to 4 in. in front of the lugs. It was decided that possibly the best way to obtain this effect was not to overlap the hardening heat but to let the steel soak for an additional 30 min before quenching. Therefore the only variable in the test steels is the length of time the shank ends were in the furnace. The remaining drill steel shanks were treated as follows: Heat treatment in pyrometer-controlled furnace at 1550°F. Quenching oil at 105°F to 125°F temperature. Areas for heat treatment were; shanks, 11 in.; threads, 9 in. Time at heat, standard practice, 20 min for 11/4-in. steel. Actual drilling tests were made in greenstone, (a metamorphosed basaltic rock), and in epidosite. Greenstone has a specific gravity of 2.96 and a compressive strength of 44,200 psi. Epidosite has a specific gravity of 3.26 and a compressive strength of 63,100 psi. All drilling tests were made using a 31/2-in. column-mounted, automatic feed drifter, with a controlled air pressure of 90 psi at the throttle. Tungsten-carbide bits of 2 in. diameter were used for all drilling. Contrary to expectations the drill steels that were allowed to soak for the additional 30 min before quenching performed better than the steels that were heat treated according to standard practice. This performance, as shown in Table I, was especially noticeable in the drilling of epidosite. The "longheat" drill steels furnished by Company "A" drilled 154 pct more minutes than the "standard-heat" steel. Expressed in feet, the "long-heat" steel drilled 114.60 ft more before failure than the "standard-heat" steel. The "long-heat" steel furnished by Company "B" drilled 37 pet more minutes or 60.39 ft more before failure than the "standard-heat" drill steel. The effect of the long heat treatment was not as evident when the steels were drilling in greenstone (Table II). In greenstone, the increase in minutes drilled by the "long-heat" steel over the "standard-heat" steel was 47 pet and 1 pet, respectively, for Companies "A" and "B."

Jan 1, 1952

By Quanjun Liu, Rongping Lin, Rongdong Deng

Arsenic contamination significantly affects the quality of copper concentrates, presenting challenges during smelting processes. Considering that covellite and enargite have similar surface properties, they are difficult to separate by flotation, resulting in copper concentrates with excessive levels of arsenic. To address this issue, this study systematically investigated the flotation separation of covellite and enargite in microflotation and bench-scale flotation tests using calcium lignosulfonate as a depressant, with the results indicating that calcium lignosulfonate can be used to separate covellite and enargite because it enables the separation of arsenic-bearing copper minerals into high- and low-arsenic (As 0.57%) copper concentrates. According to contact angle and adsorption tests, scanning electron microscopy–energy dispersive spectroscopy, and X-ray photoelectron spectroscopy, the differential adsorption of calcium lignosulfonate onto covellite and enargite is the primary reason for their distinct flotation behaviors in the presence of calcium lignosulfonate. The selective depressive effect of calcium lignosulfonate provides a novel approach for improving the flotation separation of arsenic-bearing minerals from copper sulfide minerals.

Feb 28, 2024

By J. R. Koehler

The failure of yield pillar-based gate mad designs to provide adequate ground control performance is primarily related to the use of "critically" sized chain pillars. A "critical" pillar is one that falls into a range of pillar sizes that are too large to either yield nonviolently or yield before the roof and floor sustain permanent damage, but are too small to support full longwall abutment loads. To directly compare the in-mine performance of critical and yielding pillar designs, the U.S. Bureau of Mines recently completed a field study in a tapering gate road at the Sunnyside No. 1 Mine, Sunnyside, UT. Extreme pillar stresses and associated coal bumps characterize the response to first panel mining of a 16.8-m-wide critical design. Significantly lower pillar stresses, early yielding of the pillar and adjacent panel rib, and an absence of coal bumps suggest that a narrower 12.2-m-wide design more closely approaches proper yield pillar dimensions. Probehole drilling of several 10.6-m-wide pillars revealed low stress levels and substantial pillar and panel rib yielding prior to abutment onset. suggesting a properly functioning yield pillar design.

Jan 1, 1995

By Carl Belser

This paper, covering Chaffee, Fremont, Gunnison, Lake, Larimer, Park, and Summit Counties, Colo., is the second of a series reporting on the tungsten potential of the Colorado region. The assembled information was obtained by examination of some properties, personal contacts with owners, and access to unpublished reports by other engineers. The tungsten-bearing areas of the 7 counties cover approximately 400 square miles and are in 10 distinct areas, which vary in size (fig. 1) from 1 square mile up to 290 square miles. The tungsten mineral wolframite was discovered by a man named Hackay near Dale on the Florence & Cripple Creek Railroad in the early 1900's, and wolframite and hubnerite were noted at Climax and the adjacent areas in Lake and Summit Counties at an early date, but no records of shipment from any of the areas are available before World War II. It is not known when scheelite was first discovered, but it was recognized in the Stockton mine during World War I. In the counties listed 64 properties are known to contain tungsten; of these, 18 have had some commercial output, although only 3 of them produced in 1953. The total production through 1953 is estimated at 115,000 short-ton units of tungsten trioxide. In 1953 by far the major portion came from the Climax mine.

Jan 1, 1956

By S. H. Ash

No single factor in modern civilization has played a more important part in the lives of our people than mechanization in industry and to it civilization owes much of its progress. In no industry has mechanization met more opposition than in coal mining, where ?the introduction of mechanical equipment has been opposed on many fronts for economic and social reasons. The term 'mechanization? as used in this report refers to the application of machinery to cutting, loading, and transporting coal from the face to the mine cars. During 1933, 84.7 per cent of the underground production of the bitu-minous-coal mines of the United States (1) was cut by machines, while in Washington only 17.6 per cent was machine-cut. Information in this report has been obtained from personal observations and from operating officials in the Roslyn-Cle Elum coal fields, especially D. R. Swem, manager of coal operations, and Thomas Murphy, superintendent, of the Northwestern Improvement Company, to whom the author is indebted for assistance. INTRODUCTION Although Washington coal-mining problems relating co mining methods, ventilation, drainage, and preparation of coal have been discussed in many publications, little has been published on mechanization in this region, principally because it has not been accepted generally that mining machines, mechanical loaders, and conveyors are necessary or economically adaptable to the variable and steeply inclined coal beds of Washington. Production of coal in Washington reached its maximum in 1918, when 4,128,424 short tons were produced; from that year, the trend was downward until 1934, when production was 1,383,103 short tons, the lowest since 1898; for the past two years, production has risen steadily.

Jan 1, 1937

By Robert C. Stephenson

Large deposits of titaniferous magnetite occur associated with anorthosite and gabbro in the Lake Sanford area, Essex County, New York. The ore, gabbro, and anortbosite show consanguineous relations. Anorthosite grades through gabbroic anortbosite into gabbro but is locally intruded by gabbro. Structural and petrographic evidence suggests that gabbro was differentiated from anorthosite by filter pressing. Field and laboratory study of ore occurrences indicates that an ore residuum concentrated in the gabbro through magmatic segregation' by normal crystallization and flowage. Ore occurs as bands which grade into gabbro, and also as large masses which replace anorthosite. Ore in the gabbro is finer grained and richer in ilmenite than ore in anorthosite. Introduction The Lake Sanford area lies in the heart of the Adirondack Mountains, in the southeast portion of the Santanoni Quadrangle (Fig. I), and there are four ore bodies in the area immediately surrounding Lake Sanford. The area lies 30 miles by highway from the railroad at North Creek. The deposits were discovered in 1826, and from then until 1858 iron was produced in small quantities. They were idle from 1858 to 1906. Between 1906 and 1913, extensive development work was carried on. These early attempts to produce iron ore were thwarted by transportation difficulties and by the titanium content of the ore, which, ironically, has been the element responsible for the present development. In 1941 the National Lead Co., Titanium Division, developed the Sanford Hill ore body and is now producing ilmenite and magnetite concentrates.18 The Defense Plant Corporation is extending the railroad to the property from North Creek and is building a sintering plant to treat the magnetite concentrate. Investigations OF the Deposits* Early studies of the Lake Sanford titaniferous magnetite deposits were made by Emmons in 1842,l2 by Kemp, in 1897-98'0 and by Newland in 1908.22 Singewald26 and Osborne23 considered these deposits along with numerous other titaniferous magnetite deposits in 1913 and 1928, respectively. None of these reports entailed a detailed study of the ore occurrence in this area. The present study was begun in 1940. Seven months were spent in the field, and considerable time was spent in labora-

Jan 1, 1949

By Robert C. Stephenson

Large deposits of titaniferous magnetite occur associated with anorthosite and gabbro in the Lake Sanford area, Essex County, New York. The ore, gabbro, and anortbosite show consanguineous relations. Anorthosite grades through gabbroic anortbosite into gabbro but is locally intruded by gabbro. Structural and petrographic evidence suggests that gabbro was differentiated from anorthosite by filter pressing. Field and laboratory study of ore occurrences indicates that an ore residuum concentrated in the gabbro through magmatic segregation' by normal crystallization and flowage. Ore occurs as bands which grade into gabbro, and also as large masses which replace anorthosite. Ore in the gabbro is finer grained and richer in ilmenite than ore in anorthosite. Introduction The Lake Sanford area lies in the heart of the Adirondack Mountains, in the southeast portion of the Santanoni Quadrangle (Fig. I), and there are four ore bodies in the area immediately surrounding Lake Sanford. The area lies 30 miles by highway from the railroad at North Creek. The deposits were discovered in 1826, and from then until 1858 iron was produced in small quantities. They were idle from 1858 to 1906. Between 1906 and 1913, extensive development work was carried on. These early attempts to produce iron ore were thwarted by transportation difficulties and by the titanium content of the ore, which, ironically, has been the element responsible for the present development. In 1941 the National Lead Co., Titanium Division, developed the Sanford Hill ore body and is now producing ilmenite and magnetite concentrates.18 The Defense Plant Corporation is extending the railroad to the property from North Creek and is building a sintering plant to treat the magnetite concentrate. Investigations OF the Deposits* Early studies of the Lake Sanford titaniferous magnetite deposits were made by Emmons in 1842,l2 by Kemp, in 1897-98'0 and by Newland in 1908.22 Singewald26 and Osborne23 considered these deposits along with numerous other titaniferous magnetite deposits in 1913 and 1928, respectively. None of these reports entailed a detailed study of the ore occurrence in this area. The present study was begun in 1940. Seven months were spent in the field, and considerable time was spent in labora-

Jan 1, 1949

By Albert L. Toenges

This paper is the third of a series4/ that describes some methods and practices of mining coal mechanically where operations are conducted on more than one shift. The mining of coal by means of mechanical devices has emphasized the need for continued study of the relationship, of these devices to existing physical conditions and to planning of the operations for increased safety and economy. The purpose of this investigation is to stud the operations of different types of mechanization used in mines under various systems of mining and physical conditions to reach conclusions as to the safest and most economical methods and practices of mining. Physical conditions very in different and in the same mining districts and determine, together with economical conditions, the systems of mining and the types of mechanical loading equipment used. The information presented in this paper

Jan 1, 1941

By A G. Tomkins

"Approximately 32 per cent of the worldÆs total gold production has come from greenstone belts (Frimmel, 2008). In these regions numerous small to large, quartz vein-associated gold deposits are hosted in metamorphic rocks ranging from lower greenschist to granulite facies. Historical exploration has focused its efforts on rocks of greenschist to lower amphibolite facies because these seem to contain the most deposits. Consequently, these regions are now reaching mature brownfield status, particularly in developed nations, and finding new deposits is becoming progressively more difficult. In comparison, regions of similar tectonic setting, but instead containing high-grade metamorphic rocks of mid-amphibolite to granulite facies, have received little attention because the first explorers found fewer deposits there.However, these regions certainly do contain some very significant gold deposits such as Hemlo in Canada (~684 t Au), Renco in Zimbabwe (~31 t Au mined since 1980), the very profitable Challenger deposit in South Australia (~36 t Au; recovered + reserve + resource), and the most recently discovered Tropicana deposit in Western Australia (~182 t Au; reserve + resource). High-grade metamorphic terrains therefore offer explorationists an excellent opportunity to move onto relatively green fields within developed nations, which carry less risk associated with development. However, explorationists have comparatively little knowledge of the geological controls on gold distribution in high-grade terranes because: industry experience lies in traditional lode-style gold deposits these gold deposits are geologically more complex there has simply been minimal research conducted on these deposits as a holistic group.Furthermore, research conducted in the last five years has shown us that the previous widely accepted model for gold genesis in these terranes, the crustal continuum model, is incorrect. Here, I discuss features from several gold deposits hosted in high-grade metamorphic rocks and use these to define two categories for explorationists to consider: deposits that formed prior to peak metamorphism (metamorphosed gold deposits) deposits that formed well after peak metamorphism (post-metamorphic gold deposits). There are none that have been convincingly shown to have formed during peak metamorphism.CITATION:Tomkins, A G, 2013. Gold deposits in highly metamorphosed terranes, in Proceedings World Gold 2013, pp 23-26 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 26, 2013

By Shigeatsu Nakazawa

Activities of Bi and In in the Bi-In liquid alloy were measured over the whole range of eomposition at the temperatures from 850K to 1050K. An alloy was vaeuum-sealed in a quartz cell and heated at the temperature of interest. The absorption for 307nm radiation from Bi lamp was measured for Bi atom vapor in the cell. By heating a pure metal as a standard and measuring the absorbance as a function of the temperature, an analytical curve for Bi atom vapor was constructed and used for conversion of the absorbance to the vapor density. Bi activity was determined as the ratio of the Bi atom vapor density over the alloy to that over a pure metal. The same procedure was applied to the In 304nm radiation from In lamp and In activity was determined independently of Bi. Results showed that the liquid Bi-In system behaves like a regular solution.

Jan 1, 2003

By Adrian J. Mathias

This report presents the results of an investigation of a mine production-scheduling model and a critical path analysis for long-range mine planning. An example is given to illustrate how these techniques might be used to plan long-range development and production scheduling for a large underground mine. The model, based on estimated ore block grades and tonnages, and on designed mine development layout, simulates mining of ore blocks in a sequence necessary to fulfill mill requirements for ore tonnage and grade evaluation within pre-established system restrictions. Simulated production schedules are obtained as output from the model. These production schedules are then incorporated into a critical path analysis to determine the sequence for the long-range development work so as to fulfill the production schedules and thereby meet the ore grade and tonnage requirements of the mill.

Jan 1, 1967

By M. E. Hawkins

Mineral analyses and electrical resistivity measurements of 324 representative samples of oilfield brines from 24 oil-productive counties in Mississippi and Alabama are presented in tabular form. Results of the mineral analyses, which include calcium, magnesium, carbonates, bicarbonates, sulfates, chlorides, sodium, and barium (with strontium if present), are reported in milligrams per liter. Electrical resistivity measurements in ohm-meter2 per meter at 75° F are reported in ohm-meters in the tables. Chemical analyses of formation waters are helpful to operators having water problems associated with petroleum recovery; electrical resistivity values are helpful in making interpretations from electric logs.

Jan 1, 1963

By R. Shimpo

Equilibrium calculations by a computer may sometimes fail in giving solutions when the system includes a large number of components and more than three phases, and especially when no definite information about stable phases is given. An improved method of calculation is presented in which the number of phases need not to be initially fixed, phases can appear or disappear in the course of' calculation and a new method is combined with the Newton-Raphson method to obtain solutions easily. The improved method is applied to the copper smelting operation and all the successive stages of the operation are successfully simulated.

Jan 1, 1983