Search Documents

By James C. Barker

Concern over the availability of domestic critical and strategic mineral supplies has led the Bureau of Mines to evaluate the reserve development potential of alternative sources in Alaska. Near the village of Platinum, on the southwest Alaska coast, the Red Mountain concentrically zoned ultramafic complex is a source of onshore alluvial placers containing platinum-group-metals (PGM). It has long been suggested that valuable placers may also underlie the shallow coastal waters of the Bering Sea. A direct correlation of placer PGM and chromium to ultramafic rocks in the area was studied by the Bureau and the extent of the complex was mapped. Magnetometer and gravity data and geological studies suggest the complex is a large lensoidal body trending several kilometers offshore to the southwest with a probable steep southeasterly dip. Multiple Pleistocene glaciations and marine transgressions have eroded the western and southwestern portion of the complex. Sediments containing PGM, chromium, and associated gold (largely derived from glacial till) have been transported northward along the advancing coastline by littoral currents. Beyond the breaker zone, these sediments are generally buried by recently winnowed sand and gravel transported by strong longshore tidal currents. There is also evidence that paleoplacer channels underlie the marine sediments.

Jan 1, 1986

By L. J. Gurevich

IN the course of the examination, at the Bureau of Standards, of fusible tin boiler plugs for the Steamboat Inspection Service, it became evident that an investigation should be undertaken to determine the precautions necessary in the manufacture of acceptable plugs. The results of the tests of these plugs show that their manufacture has improved, though at present not all of the plugs tested are satisfactory. Table 1 gives the result of tests of some 1500 plugs from about 100 makers. Records of the tests show that several of the makers were able to produce satisfactory plugs with every pouring. The Steamboat Inspection Service has the following specifications for fusible plugs: "Fusible plugs for use in boilers of steam vessels under the Jurisdiction of the Steamboat Inspection Service shall be made of bronze casing with the bore tapering continuously and openly from end to end, and filled from end to end with tin not less than 99.7 per cent. pure and to contain not more than 0.1 per cent. of lead and not more than 0.1 per cent. of zinc. The small end of the bore may be countersunk not more than 1/32 in. in depth and width, but no recess, thread, or cavity other than this countersink shall be allowed."

Jan 8, 1919

By Tony Weeks, J. Loah, Ian Mcgaffin

PT Newmont Minahasa Raya (PT NMR) operates a 700,000 tonne per annum open cut gold mine in the Minahasa region of North Sulawesi. The operation commenced production in the second quaiter of 1996 and is expected to produce an average of 150 000 to 180 000 ounces of gold per year for the mine life. The deposit is predominately refractory in nature and requires a complex treatment route incorporating dry milling and whole ore roasting followed by conventional cyanidation and adsorp­tion of the gold onto activated carbon. Gold is eluted from the carbon to produce <lore bars assaying approximately 94 percent gold. A scrubbing system for the removal of mercury from the roaster off gases was commissioned in late 1997. Due to the location of the operation, close to the coast and in seismic region with high rainfall submarine tailings placement (STP) was the preferred method of tailings disposal. Prior to dis­posal into the ocean the tailings from the CIP plant are detoxified in a three stage detoxification circuit to treat cyanide, arsenic and mercury. This paper reviews some of the design and operational fea­tures of the whole ore treatment process employed at the Minahasa Gold Mine.

Jan 1, 1998

By W. E. Young

Iron ore occurs in abundance in Iron and Washington Counties in southwestern Utah. Outcrops are encountered over a wide area extending from Paragonah on the northeast to Bull Valley on the southwest. Outcrops also occur on the Wah Wah Range and on Blue Mountain on the north edge of Iron County. The greater concentration of known deposits occurs in and around the margins of three mountainous uplifts - Iron Mountain, Granite Mountain, and Three Peaks - comprising a belt about 3 miles wide and 23 miles long (fig. 1). This area was partly explored by the Bureau of Mines in cooperation with the Geophysical Division of the Bureau of Mines and the Geological Survey under the strategic minerals program during 1942 to 1945. The exploratory work comprised geological and topographic mapping, geophysical prospecting with a magnetometer, diamond drilling, trenching and test pitting, sampling ore exposures and old workings, and constructing and repairing roads. The Pinto-Iron Springs district is the most important known source of iron ore for the steel plants of the West. The future economic status of the Intermountain and Pacific coast regions will depend largely upon the successful development and exploitation of substantial iron-ore bodies in this district.

May 1, 1947

Illustrated guidebooks treating in a popular descriptive way of the geology and other features of the Western United States have been issued by the U. S. Geological Survey. They will be of much interest to mem¬bers in connection with the Arizona Meeting of the Institute and espe¬cially the guidebook of the Santa Fe Route, with side trips to the Grand Canyon, containing as it does relief maps, topographical and geological maps, covering the entire route of the railroad, illustrations from photo¬graphs and other interesting descriptions of this great country. The method of treatment is adapted to the lay-reader, although it includes much valuable and interesting technical information concerning the geographical and other features. The books are well indexed. These volumes sell for 50 c. each and may be obtained from the Superintendent of Documents, Washington, D. C. These guidebooks originally sold for $1 each, but the reprint edition has been reduced to 50 c. A list of the different guidebooks follows: Bulletin 611. Guidebook of the Western United States, Part A, The Northern Pacific Route, with a Side Trip to Yellowstone Park, by M. R. Campbell, and others. 1915. 212 pages, 27 route maps, 27 plates, 39 text figures.

Jan 6, 1916

At its meeting on February 21, 1933, the Board of Directors passed the following resolution defining and expressing the policy of the Institute with respect to official participation or action in controversial matters: WHEREAS, the Board of Directors at its last meeting passed the following resolution: "The Board of Directors, having been appealed to by several Local Sections for advice concerning the attitude and policy of the Institute relating to the endorsement of candidates for public office, the following statement of policy is formulated: "Whereas, the American Institute of Mining and Metallurgical Engineers is organized for purely professional and scientific purposes, and whereas diversity of opinion among its members on partisan or political questions is inevitable, it is the expressed policy of the Institute to refrain from official participation or action in political and semi-political matters." AND WHEREAS, appeals for additional advice have been received: NOW, THEREFORE, IT IS RESOLVED: (1) That the policy of the Institute is to refrain from official participation or action in controversial non-technical economic subjects; further (2) That if any Local Section is in doubt as to the application of this policy to any particular subject, it should communicate with the Secretary of the Institute for advice.

Jan 1, 1940

No early records of coal in Iowa have been found, although it is very probable that coal along the Mississippi, in the northeastern corner of the state, was seen very early. The United States Census of 1840 showed a production of 400 tons, mined of course in 1839, and the earliest mining, was in Jefferson and Fairfield Counties where the coal was hauled by wagons to shops in the Mississippi River towns years before any railroad was built in the state. In 1840 mines were opened in Van Buren County, near Farmington and Douds, and in Scott County, near Jamestown, all of the product being used locally.&apos; In 1844 D. D. Owen reported seeing mines in the tongue of land between the Rock and Mississippi Rivers, in one of them the coal being 5 to 6 ft. thick, and several other seams south of this locality? In the, late forties a number of small mines were opened in various parts of the state, and in following years in practically every county having coal. The Mystic seam was first opened in 1857 in Appanoose County, since then consistently one of the large producing areas in the state. Consumption was local until the Milwaukee Railroad was built through the county in 1887.1

Jan 1, 1942

By Dan Johnson

The discovery of rich alluvial diamond deposits on Namibia?s Skeleton Coast in 1908 began a period of intense exploration and mining off the coastal sand; and shallow surf zones. In the mid-60s a Texas entrepreneur, Sam Rollins took the search to the seafloor. The inhospitable conditions encountered made the early going difficult. After a slow start, the past 10 years have seen much progress in geologist?s understanding of the deposition mechanics and the use of sophisticated geo-physical and sampling techniques to aid in the discovery of economic deposits. Diamondfields, in a joint venture with BHP and Benguela Concessions, began an exploration program in 1994 for sea-bed diamonds off the Port of Luderitz in Namibia. This program has progressed to a mine development program with the potential of creating a 500,000 carat per year operation. The mining technologies being considered include state-of-the-art, remotely operated sea-bed crawlers and high volume dredges feeding to semi-mobile processing platforms. The company&apos;s objective is to use the best proven technology to create an environmentally responsible operation with the lowest fixed operating costs and the longest and safest weather operating window of any offshore operator working Africa&apos;s diamond coast.

Jan 1, 1998

At its meeting on February 21, 1933, the Board of Directors passed the following resolution defining and expressing the policy of the Institute with respect to official participation or action in controversial matters: WHEREAS, the Board of Directors at its last meeting passed the following resolution: "The Board of Directors, having been appealed to by several Local Sections for advice concerning the attitude and policy of the Institute relating to the endorsement of candidates for public office, the following statement of policy is formulated: "Whereas, the American Institute of Mining and Metallurgical Engineers is organized for purely professional and scientific purposes, and whereas diversity of opinion among its members on partisan or political questions is inevitable, it is the expressed policy of the Institute to refrain from official participation or action, in political and semi-political matters." AND WHEREAS, appeals for additional advice have been received: NOW, THEREFORE, IT IS RE¬SOLVED: (1) That the policy of the Institute is to refrain from official participation or action in controversial non-technical economic subjects; further (2) That if any Local Section is in doubt as to the application of this policy to any particular subject, it should communicate with the Secretary of the Institute for advice.

Jan 1, 1946

The following petition for amendment of the constitutional provisions relating to qualifications for membership in the Institute, signed by 75 members, of whom 27 are members of the Committee on Increase of Membership, was received by the Board of Directors, was printed on the program of the New York Meeting sent to all members early in January, and is now being voted upon by the membership: In accordance with the terms f Article X, we hereby propose the following amendment to the Constitution, Article II, Section 2: Members shall comprise all those persons who on the third Monday of February, 1918, were members of the Institute, and in addition thereto, all those thereafter, elected or transferred into the, class of Members. A person to he eligible for election or transfer into the class of Members must he at least 27 years of age and must have had at least six years&apos; employment in the practice of engineering, mining, geology, metallurgy or chemistry, during at least three years of which he must have held positions of responsibility in one or more of these fields. Graduation from the scientific course of a college, approved by the Committee on Membership, shall be considered equivalent to two years&apos; employment, as required in the previous sentence.

Jan 2, 1918

By Sherrill Gardner

Vibratory drivers have been used since the 1930s to drive and extract piles. Vibratory pile drivers have the capability of significantly decreasing pile installation time, especially in granular type soils. However, they have not been widely accepted because of the uncertainty in estimating the bearing capacity of the driven pile. When driving bearing piles, the industry standard method for obtaining load carrying capacity of a pile installed with a vibratory driver is to redrive with an impact hammer. The advantage of improved productivity is lost with the redrive procedure. Currently, there is no other method to predict the capacity of these bearing piles installed with a vibratory driver. The Naval Civil Engineering Laboratory (NCEL) is making progress towards being able to estimate the bearing capacity of these piles. This paper describes field testing and corresponding analytical modeling of the vibratory driver-pile-soil system. The following sections describe the development of the numerical model and techniques for collecting field data. A discussion of the prediction of the pile driving process based on field test data is followed by suggestions as to the additional work that should be done to further verify the model to a point where it can be used with confidence.

Jan 1, 1987

The Office of Price Stabilization broke the copper price loggerhead between the U. S. and Chile when it permitted copper wire and brass mills to add to their ceiling prices 80 pct of the increase in cost of foreign copper above the 27 1/2 cents per pound specified in the agreement with Chile. Another step forward in the processing of taconite seems to have been made with the patenting of a process for the strengthening of taconite pellets. The patent was issued to Fred D. De Vaney and assigne to the Erie Mining Co., of Hibbing, Minn. Strength of the pellets is improved by adding from one to five pounds of starch or sodium silicate. A new iron ore deposit discovered on Vancouver Island will start producing soon, and is expected to yield 2 million tons of magnetite over its span of operation. A new mill will be built by the Argonaut Construction Co., of San Francisco, at the deposits of the Utah Construction Co., its parent organization. The Organization for European Economic Cooperation banned the use of nickel and nickel alloy in the manufacture of about 500 products in an attempt to conserve nonferrous metals in short supply. Some 18 members of the organization have already volunteered to restrict nickel consumption.

Jan 1, 1952

By Roswell H. Johnson, W. E. Bernard

To know the rate of declinc of oil wells is very important, yet ordinarily we are prevented from getting this rate because the oil from several wells is put into one or a few tanks as soon as the wells have been connected to the power. The object of doing this is economy of tanks, pipes, labor, and accounting. But we are making a great sacrifice for this small economy. The advantages of the individual records are that we would know better: 1. When the well has ceased to be profitable. 2. When a well has gotten into bad condition. 3. The real record of the yield per acre and the rate of decline of the wells. The lease total is too mixed as to age of the wells for existing records to have much significance. To obtain such individual well records and more accurate logs are the great desiderata of satisfactory management of oil properties. 4. Which wells show the slowest decline—information which is valuable in locating new wells or purchasing adjoining leases. The truth of this statement is evident, when we reflect upon the large number of purchases of producing property. Intelligent appraisal is of the utmost advantage and it is impossible without individual well-pro-

Jan 1, 1918

By Clark J. Gilbert

The mining method at the Cannon mine uses heading and bench stopes, which are subsequently backfilled with cemented high-strength fill before pillar removal. The dimensions of the pillars are 7.3 m wide by 19.8 to 28.9 m high (24 ft by 65 to 95 ft). They require careful blasting in order to not damage the rock, compromising pillar strength and complicating later removal. Additionally, the proximity of dwellings makes vibration control a must for good neighbor relations. A blast monitoring study was conducted in order to optimize bench blasting practices to maximize fragmentation, reduce costs, and to minimize wall damage and ground vibration. The Cannon mine is a joint venture between Asamera Minerals (US) Inc., a 92% owned subsidiary of Gulf Canada Ltd., and Breakwater Ltd. Asamera is the operator. The mine is located at the south end of Wenatchee, WA, a town of roughly 45,000 people on the eastern flanks of the Cascade Mountains. Gold is the primary product at the mine. The rock is extracted using a sublevel end-slicing method on 15 m (50 ft) lifts, with subsequent backfilling and pillar removal. The stope widths, dictated by rock conditions at 7.3 m (24 ft), are the same in the primaries as in the pillars, or secondaries.

Jan 1, 1990

By J. A. Eisele, G. E. McClelland, M. D. Wroblewski

The Bureau of Mines is conducting research at its Reno Research Center to develop a staged agglomeration-heap leaching system and to electrowin the dissolved precious metals from the pregnant leaching solution. For direct electro- winning to be successful, the pregnant solutions generated during the Initial stages of leaching must be higher grade than obtained by conventional heap leaching. The precious metal concentration of the pregnant solution can be Increased by agglomeration pretreatment with cyanide solution which starts the leaching process during the curing period, by leaching with small volumes of solution and by cycling the leaching solution through more than one heap in a staged manner. The resulting pregnant solution is passed directly through an electrowinning circuit. The barren solution from electrowinning is recycled to the leaching circuit. Bench-scale research on the development of the staged leaching system and on the development of an efficient electrowinning cell are described. The Bureau of Mines developed agglomeration- heap leaching technology. This technology was readily adopted by the mining Industry for heap leaching crushed ores and mine wastes. Current research involves the application of this technology to finely ground feed materials such as precious metal-bearing milled tailings. Tailings agglomeration-heap leaching has also been used commercially.

Jan 1, 1984

This paper describes an investigation of the sampling problems which contributed to erroneous Concentrator production forecasts at the mining operation of Bougainville Copper Ltd (BCL) in the North Solomons province of Papua/New Guinea.Reference figures provided by independently verified commercial shipment data demonstrated the existence of a bias in the calculated Concentrator production; the challenge was to identify systematic errors in each of the contributory measurements (feed tonnage and feed, tailings and concentrate grades).The uncertainty surrounding specific sampling and measurement errors precluded optimum metallurgical control and performance of the milling circuit, encouraged disputes about the difference between Mine versus Concentrator production estimates, and cast some doubt on efforts to follow political guidelines concerning a maximum feed tonnage or recovery oriented mill operating concept.An evaluation of routine results as well as specifically targeted test work identified the sampling errors associated with measured individual parameters.The emphasis in this report is on the procedure for quantitative error assessments.The measured performance of a mineral dressing plant is subject to a systematic error balance which can be derived from the more familiar weight and metal balances such as the two- or three-product formula.The resulting equations are generally valid, and they are applied to the measurements obtained at BCL&apos;s Concentrator to illustrate the method.

Jan 1, 1976

By Masafumi Maeda

Metal recycling and waste treatment have become common issues in various metal industries, notably, the iron and steelmaking industry and the nonferrous industry. The former tends to treat mass wastes such as municipal wastes or plastics. However, volatile compounds are condensed in dusts of their incineration processes and they should also be treated, likely by the nonferrous industry. Those "end-of-life" products contain heavy metals that might be harmful to mankind and should be handled by the non-ferrous industry. Not only revenue derived from regeneration of metals from the secondary materials but also the revenue generated from the treatment charges is a strong attraction for nonferrous industry to process secondary materials. The present study presents some statistical data of the Japanese corporations in the iron and steelmaking industry as well as the nonferrous industry on their revenues generated from processing of secondary materials. Some of the companies are now concentrating their business resources on new areas of the market. Although the quantity of waste or recyclable material is still small at present, the quantity will increase in the near future, and it is anticipated that international collaboration is required to handle the greater variety and the larger quantity of secondary materials.

Jan 1, 2004

By Brent K. Nelson, D. Lee Petersen, Charles R. Nelson

INTRODUCTION The Soudan 2 Cavern was completed in 1986 as a physics research laboratory located 713 m below ground in northern Minnesota. A paper in the 1985 RETC proceedings presented the background and planned usage for the cavern, site investigation and rock conditions, contract documents, and a bid summary. This is a follow-up paper describing construction of the cavern. The Soudan 2 excavation, 71.8 m long by 13.9 m wide by 11.6 m high, was excavated by drill and blast methods and mucked by crawler tractor and mine hoist. The excavation sequence consisted of twin top-heading pilot tunnels followed by removal of the top heading pillar and finally the bench. Various blasting designs were used to achieve adequate breakage and acceptable levels of blast damage control at the cavern perimeter. The geologic conditions exposed in the cavern, and the support needs of the rock encountered, are compared to the conditions interpreted from the site investigation. The influence of specific geologic features on cavern performance will be described. Initial support and final lining consisted of full length grouted rockbolts and reinforced and plain shotcrete. Trials were conducted with steel-fiber reinforced shotcrete and microsilica additives. The performance of the rock and support systems was tracked with single point extensometers, convergence measurements

Jan 1, 1987

By E Wan, K Stokes

Since 1978, the nickel concentrator at Leinster has been subject to continuous change. In 1971 a significant nickel sulphide deposit was discovered on Leinster Downs Station, within three years the extent of the deposit was determined. In 1978 the Agnew Mining Company began production of nickel concentrate from the Perseverance Mine and continued to do so until production ceased in 1986. In 1988 WMC purchased the mothballed project and began the first phase of many expansion initiatives. Milestones in the life of Leinster have included:open cut mining of the Perseverance orebody and the discovery of the RockyÆs Reward orebody, as well as the metallurgical challenges in treating each of these; underground mining at both Perseverance and RockyÆs Reward; construction and commissioning of the WMC grinding and flotation circuits; variations in the reagent schemes, including the introduction of æliquidÆ reagents; development of mill linings to reduce maintenance; circuit re-configuration and simplification; development of Harmony open cut; strategies for increasing throughput at the drier; and changes to tailings facilities to cope with increased throughput. This paper outlines the steps which have been required to expand the Leinster Nickel Concentrator from 650 000 tpa to 2.5 Mtpa and those steps which will be required in the future.

Jan 1, 2000

By Thomas J. Regan

The first stage of the Massachusetts Bay Transportation Authority&apos;s Red Line Extension Northwest, is a two-track rapid transit extension from Harvard Square in Cambridge, through three stations, to the Alewife Station/Garage complex in North Cambridge. The extension, about 5.0 km. (3.1 miles) in length, is entirely in tunnel, with the Alewife Station/Garage complex and adjacent line sections of tunnel constructed by cut-and-cover methods. The Station/Garage complex, just west of Alewife Brook Parkway, is in an area underlain by deep deposits of very soft highly sensitive clays. It is proposed to construct the station and adjacent tunnel sections by the slurry trench method, using the slurry wall as the permanent structural wall of the station and tunnel. The unusual nature of the underlying clay and its very high sensitivity raised questions concerning the feasibility of the proposed construction. Since research failed to reveal any construction precedent for the specific conditions encountered, a test section was undertaken to determine construction problems, resolve uncertainties, and to establish acceptable parameters for the construction of the slurry walls. PROJECT ORGANIZATION Sverdrup & Parcel as tunnel and transit systems consultant for the Red Line Extension-Davis Square to Alewife had overall responsibility for determining program objectives, project management and test implementation.

Jan 1, 1979