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By R. H. Duval

"In May 1936, Pamour started producing gold by cyanidation of flotation concentrates, and in 1939 was milling about 1, 600 tons per day.Refining records dating from 1939 show two oil-fired furnaces in use, (Rockwell type 46 11 x 29 11 inside oval shell).Refining time averaged 7. 83 hours during the year 1939, indicating a complete refining shift of about 9. 33 hours. That year appears to be characteristic of the period with regard to time required and results obtained.For that year total fineness (gold + silver) of the bars averaged 940 (approx.), but it frequently dropped below this figure, sometimes far below.Furnace lining life varied widely from three to seven or more months. Sillimanite was the standard lining but Mullfrax 41 was frequently used.For many years refining practice remained practically unchanged, and in 1960 procedure still consisted essentially of mixing a flux(% Composition Borax 41, Silica 11, Soda-Ash 11, Nitre 15, Mn02 22) with cyanidation precipitate in the ratio of l. 2 to l and heating to a medium heat (yellowishred, 2000° F) with a low flame for a long time. Time required was about 10. 5 hours per refining. Results were still much as detailed above.At this time it was decided to revise refining procedure, in an effort to shorten refining time and obtain consistently good bullion fineness."

Jan 1, 1965

By A. W. Fahrenwald

THE absolute efficiency of crushing and grinding in a ball mill is not known. A number of investigators have made calculations to this end and have presented efficiency figures. Two factors have prompted further investigation of this subject: (1) the unbelievably low magnitude of the values offered, and (2) a desire to obtain, if possible, true relationships between the relative efficiencies of a ball mill operating under varying conditions. A useful forward step in the study of mill efficiency was made when Martin1 and Gross and Zimmerley2 proved the correctness of Rittinger's law, and incidentally the incorrectness of the so-called Kick law, and when Gross and Zimmerley3 determined and gave surface values for Tyler sieve-sized quartz. These data are probably accurate throughout the range of the sieve scale, but on -400 mesh (which is the finest sieve available), the surface data, as obtained by the hydrofluoric acid disso-lution method, are of doubtful reliability. Any inaccuracy existing in surface determinations of -400-mesh material, especially when comparing runs in which varying quantities of this product are formed, will cause the resulting relative mill efficiency values to be distorted. Moreover, knowing surface accurately, the efficiency calculations require a surface energy figure. Two such figures are to be found in literature, one by Edser4 and one by Martin.5 Edser's surface energy

Jan 1, 1931

The following tables showing the output of coal during the year 1913 have been secured y R. H. Morris, of Pocahontas, Alberta, Canada, for the use of the Committee through the kindness of John T. Stirling, Chief Mine-Inspector of Alberta. The principal mining districts are, Crow's Nest Pass, Calgary, Lethbridge, and Edmonton, the outputs from which were as follows: Tons Crow's Nest Pass 1,849,435 Calgary...: 627,461 Lethbridge ; 966,020 Edmonton 863,430 Total 4,306,346 Of this quantity there was exported to the United States, principally from the Crow's Nest Pass district, 138,201 tons of 2,000 lb., that being the ton used throughout the Province. This production consisted of lignite, bituminous coal, anthracite, coking coal and coal used in making. briquettes, as follows: Tons "Lignite coal" (lignitic?) 1,763,225 Bituminous coal 2,374,401 Anthracite coal 168,720 Coking coal 104,012 Coke produced 65,167 Briquettes produced 130,861 The only district in which coke was made is the Crow's Nest Pass district, and the entire product was consumed in Canada. The total number of persons employed is as follows: Above ground 2,231 Underground 5,837 Total 8,068 The per capita production was as follows: Tons of coal mined per employee 533 Tons of coal mined per underground employee 737

Jan 7, 1914

By Lon Santis

Although unproven, it is suspected that there have been eleven locations since 1988 where explosive generated carbon monoxide (CO) gas moved through the earth and accumulated in nearby underground enclosed spaces. This paper summarizes the incidents, which involved about 30 suspected or medically verified CO poisonings and 1 fatality. Ten incidents occurred in residences and one occurred in a manhole. Although practically nothing is known about the mechanism behind the suspected gas migration, review of the incidents and available information indicates there are certain warning signs and a successful remediation technique available. In each case, overburden heavily confined the explosive in the blasts, preventing release of explosive-generated gases to the atmosphere. All the blasts were in residential areas, and none were excavated immediately. Where the distance from the blast was recorded, 5 of the blasts were within 20 to 50 feet (ft) (6 to 15 meters [m]) of the underground enclosed spaces, 3 were 100 to 150 ft (30 to 46 m) away, and 1 was 400 to 500 ft (120 to 150 m) away. Investigators often identified suspected pathways from the blast site into the underground enclosed spaces. One technique appeared successful at quickly correcting an existing condition. This technique involved applying negative pressure to the earth and removing the CO from the ground surrounding the underground enclosed space.

Jan 1, 2001

By Carlo Grandori

Early experiences The first double shield hard rock tunnel boring machine, manufactured in 1973, belonged to the generation of machines that were equipped with 12" dia. cutters. The experiences made with the 4.3 m diameter prototype ROBBINS mod 144-151 have been reported at the 1976 R.E.T.C. of Las Vegas (1): it might be worth recalling here that, with a specific cutter load not exceeding 10 to 12 metric ton and a 4.8 r.p.m. cutterhead speed, the average advance rate was of 350 meters per month of 21 working days with a peak production of 1,050 m of advance in 40 working days, in widely weathered and fractured granitic rocks of generally precarious stability, where a precast segmental lining was routinely installed as tunnel support. Over the 8.2 km of the Sila Tunnels, several badly crushed or sheared rock zones were bored through without major problems, even with water inflows of up to 30 1/sec. The same machine, with an improved design of the telescopic-and-floating shield area and equipped with flameproof drive motors, was taken to Colombia where, from September, 1979 to March, 1982 it drove 7.5 km of the Rio Negro-Chivor Tunnel in competent siliceous shales of up to 130 MPa at an average rate of 20 m/day.

Jan 1, 1987

By F. J. Klingler, K. M. Swaffar, M. M. Rabbaig

The Detroit Water and Sewerage Department has undertaken a $1.2 billion effort to capture and treat combined sewage overflows from various outfalls along the Detroit and Rouge Rivers in Detroit, Michigan. This program is planned to include a 455,000 m3 (120 million gallon) storage and treatment tunnel which will capture overflows from 19 outfalls along the Rouge River. The tunnel is currently in the conceptual design phase, with the bid date planned for mid-year in 2001,and completion planned for August 2005. The total design and construction cost is currently estimated to be approximately $450 million. Current concepts are for the storage and transport tunnel will be 6.1 m (20feet) in finished diameter, with a total alignment length of approximately 12,200 m(40,000 feet). The main tunnel will extend through the Traverse and Antrim Shalerock formations, while approximately 5,500 m (18,000 feet) of various diameter connecting tunnel will extend through both rock and soft ground. The project will include a total of 10 drop shafts, 13 riser shafts, various connecting structures, and a 455,000 m3/day (20 mgd) pumping station. This paper will present a discussion of the design philosophy, subsurface conditions, the various planned components, and the expected design and construction considerations for the proposed Upper Rouge Combined Sewage Overflow Tunnel.

Jan 1, 1999

By R. G. Davies

THE effect of ordered structures upon steady state creep has not been extensively studied although it has been demonstrated that the brass,' ie,' and Fe3Al3 superlattices increase the creep resistance. Suzuki and Yamamoto observed an acceleration in the creep rate of Ni3Fe below the critical temperature for order, (T, - 505"), for both the ordered and disordered states, and that the activation energy for creep was independent of the applied stress. They concluded that a dislocation climb creep mechanism was operative down to 300°C which is - 1/3 TM where TM is the absolute melting temperature. This is quite remarkable in that it is usually observed that climb controlled creep in both pure metals and alloys ceases below - 1/2 TM (590" for ie). With this anomaly in mind it was decided to reinvestigate creep in a 75 at. pct Ni-25 at. pct Fe alloy. The creep apparatus and operating conditions have already been decribed. Since Ni-Fe alloys order very slowly, it is possible to have a disordered alloy at a temperature below T,. A long anneal at a temperature just below T, produces considerable long-range order;5 the ordering treatment in the present investigation was 150 hr at 485°C which gives an antiphase domain size of-SOW

Jan 1, 1963

By E. B. Branson

Introduction to Geology, by E. B. Branson, W. A. Tarr, and W. D. Keller, revised-by Carl C. Branson. McGraw-Hill, 1952. $5.50.-Dealing with physical and historical geology, the book has been revised from an earlier edition. An attempt has been made to eliminate unnecessary detail in discussing processes and history. Revisions bring technical and statistical data up-to-date, and follow suggestions by teachers who used earlier editions. The book carries an eye witness account of the severe earthquake in Assam, India, in 1950 and the story of Paricutin and other major examples of volcanism. Charts summarize chemical weathering, and the results of metamorphisms. The book also contains many new illustrations, including aerial photographs. A History of Phelps Dodge 1834-1950, by Robert Glass Cleland. Alfred A. Knopf, 1952. $4.00.-The book traces the growth of Phelps Dodge from the day Anson Greene Phelps opened a small saddle shop in Hartford, Conn., to the present day. As the country grew, so did Phelps Dodge. The company took part in large affairs from its very beginning. It bought and sold, exported and imported, built factories and railroads, and widened its scope of operations economically and geographically. Entrance of Phelps Dodge into copper mining and the gradual giving up of other interests in favor of the new venture is traced.

Jan 1, 1952

(The following list contains the names of those members of the Institute of whose connection with military service we have only recently become acquainted; it also includes the names of a few who have recently been promoted or transferred, indicated by a *. A complete list was published in the Year Book, issued as a supplement of the Bulletin for March, 1918.) ANDERSON, AMIL A., Co. A, 309th Regiment Engineers, 84th Div., American E. F., Care Postmaster, New York. ARMSTRONG, HAROLD K., Pilot, Naval Aviation, U. S. Naval Air Station, Miami, Fla. BASSETT, ARTHUR F., Co. 6, -E. 0. T. S., Camp Humphreys, Va. BEDDALL, THOMAS H., Adjutant, 1st Battalion, 1st Gas Regiment, American E. F. BERNARD, CLINTON P., Candidate, 12th Observation Battery, F. A. C. 0. T. S., Camp Taylor, Ky. BROOKE, LIONEL, 50th Co., 13th Battalion, 5th Replacement Engineers, Camp Gordon, Ga. BROWNING, EDWARD, Corp., 1st Regiment Engineers, Co. D, American E. F. BUGBEE, EDWARD E., S. A. T. C. Headquarters, Raleigh N. C. BUTTERFIELD, G. BRUCE, CO. C, 605th Engineers, American E. F. CADOT, J. J., 1st Lieut., U. S. Air Service, American E. F., Care Post- master, New York. CARLOCK, J. B., Major, 2d Battalion, 1st Gas Regiment, American E. F., France.

Jan 12, 1918

By Jim Hall, Denis Rickman, Jon Windham, John Ehrgott, Stephen Akers, Byron Armstrong

With the growing concerns about terrorism world-wide, numerous agencies conduct experiments to investigate the effects of terrorist vehicle bombs. In many cases, the vehicle bomb of interest utilizes some form of ammonium nitrate/fuel oil (ANFO) as the explosive source. Due to the high cost of fullscale testing, it is advantageous to conduct at least some vehicle bomb experiments at reduced scale. Extensive testing has shown that ANFO is a non-ideal explosive, and its explosive output does not scale reliably at explosive masses below approximately 400 lb (182 kg). Most scale-model testing requires explosive masses 1 to 5 orders of magnitude smaller. Thus, scale-model testing is typically conducted with “ideal” explosives, such as composition C-4, which perform in a scalable manner at virtually any charge mass. The utilization of an ideal explosive to model ANFO requires the existence of an accurate means of equating the performance of the two explosives. The airblast equivalence of C-4 and ANFO has been well established. However, the cratering equivalence of these explosives is not thoroughly quantified. This is especially true for the case of an above-ground detonation, which is precisely the scenario of interest in vehicle bomb studies. A study has been conducted to better define the cratering equivalence of C-4 and ANFO for above-ground detonations. This paper presents a discussion of results from this research.

Jan 1, 2008

By Kissell F. N, Volkwein J. C

The U.S. Department of Interior's Bureau of Mines has the opportunity to visit many U.S. mines, including some that claim 2 to 5 times the national average of 334 raw tonnes/unit shift (tps) from a continuous miner section. In a project to assess the reasons for this high production, the Bureau conducted two studies. The first study focused on the 25 highest producing continuous miner sections. What stood out during the visits-was the quality of the labor-management relations. In each of the mines there was a positive labor/management relationship based on mutual trust and a sense that the employees were the company's most valuable resource. Discussions with labor revealed a universally positive attitude toward the company. Interviews with the mine superintendents invariably ranked the quality and attitude of workers as more important than anything else. Also during the mine visits of the 25- mine study, no engineering factors obviously stood out. Time at the face was greater than average, most were in coal over 1.52 m and the roof was generally good. Also, none of the 25 mines had to contend with high methane levels. Because this study found that a high percentage of mines were in seams less than 1.52 m thick, the second study examined thin seam mines only.

Jan 1, 1988

By John S. Jones, Ralph E. Brown

INTRODUCTION For more than a century, artificial ground freezing has been used for groundwater control and structural support for excavations. Most of the early uses of the freezing method were for sinking deep access shafts for mines and tunnels (1,2,3,4). More recently, ground freezing has increasingly been used for construction of large diameter cofferdams and soft-ground and mixed-face tunnels (5). Although ground freezing has been used in the past-for tunnels, it was invariably used as a last resort measure, where more conventional measures could not be used. The more recent freezing applications, however, have become increasingly cost competitive with more conventional techniques, and are now being included as part of the design concept (6,7,8,9,10,11,12). The purpose of this paper is to describe some of the more recent applications of ground freezing for tunnel construction. The paper begins with a brief description of the most commonly used freezing system, the Poetsch process. Recent tunneling projects utilizing ground freezing for structural support are then discussed. DESCRIPTION OF THE FREEZING METHOD The most commonly used freezing method is the Poetsch process, which was originally developed by F. H. Poetsch in the late 1800's. The system consists of a brine coolant, typically calcium chloride and water. Freezepipes are placed into boreholes or are

Jan 1, 1979

By Sooi P. Chong

Expansion of concentrator capacity at Iron Ore Company of Canada's Carol Lake plant resulted in a dramatic increase in the production of fines. With iron recovery from the fines running only 18%, Carol Lake engineers initiated an extensive test program which resulted in the installation in July 1977, of a full-scale plant utilizing Reichert cone concentrators. Results to date have indicated a 100% increase in iron recovery from the concentrator's fines product. Carol Lake is located near the western boundary of Labrador, Newfoundland, some 960 km (600 mi) northeast of Montreal. Concentrator operations began in 1962 with a design capacity of 7 million t/y (7.7 million stpy). The bulk of the concentrate was pelletized at a 6 million t/y (6.6 million stpy) pelletizing plant completed in 1963. The remaining concentrate was sold in the international market. The concentrator was first expanded in 1966 to 10 million t/y (11 million stpy) capacity. In 1967, the pellet plant was expanded to match the increase in concentrate production. Sales increases led to a further expansion in 1973. By 1977, more than 40 million tons (44 million st) of crude ore were processed to recover in excess of 17.42 million tons (19 million st) of concentrate and 10.4 million tons (11.5 million st) of pellets.

Jan 12, 1978

By Michel Guillot

Gaz metal arc welding is commonly used for producing large frames and assemblies. Even for light aluminum and thin wall assemblies, the GMAW technique is increasingly preferred over the GTAW technique. This is particularly true where the welding gun motion is achieved accurately with automated or robotic systems and when using pulsed or regulated metal deposition. In this study, butt joints in floor welding position are tested at speed ranging from 1.5 to 16 m/min. Attempts are made of find parameters providing good and repeatable joint quality with minimal distortion and good appearance even at high travelling speeds. Taguchi experimental plans are proposed with different parameters tested with sheet metal samples. The parameters include typical GMAW machine settings, joint preparation geometries, wire gages, gun angles, wire feeds, and more. The robot motion speed and the proximity of the part are also considered. Direct monitoring of machine welding current and voltage is achieved. Once is found the best set of parameter settings, additional tests are carried out to verify the repeatability of weld quality. Secondly, these conditions are applied for joining and testing a floor panel made of several extrusions. Weld quality is established with Vickers micro-hardness measurements, cross section geometries of the weld pool including penetration, tensile tests and metallographic observations to establish the amount of porosity and weld microstructure in the HAZ.

Jan 1, 2011

By W. E. Wallace, P. Bolsaltis, M. J. Keane, B. L. Rauaboni

Thermal treatment of respirable size silica dust samples results in marked changes in their hemolytic activity. These changes can be correlated with changes in the characteristics of the particle surface as measured by infrared spectra, zeta potentials, and specific surface area. Silica samples from various sources (Min-U-Sil, fumed silica, and a NIOSH standard sample) were heated or calcined at temperatures ranging from 100-1095C. The hemolytic activity of the crystalline materials decreased after thermal treatment. The behavior of the fumed material was found to be more complex. Material of very large surface area (small particle size) exhibits an initial increase in hemolytic activity upon calcination. This result confirms other experimental observations pointing to a particle size of maximum toxicity. Tre changes in hemolytic activity can be related to infrared spectra and zeta potentials of the materials. The absorption band in the 3200-4000 cm-1 frequency region of the fumed material disappears upon heat treatment while a sharp, characteristic band at 3750 cm-1 increases in intensity. Zeta potential measurements conducted in the pH range of 2.0-10.5 exhibit a unique change in zeta potential v.s. pH profile with heat treatment. These findings indicate that the removal of active surface silanol groups by calcination results in reduced cytotoxicity, as measured by a hemolysis test.

Jan 1, 1988

By Derek Ellis

There are two environmental issues which have only recently begun to need planning in detail for marine mining. One is the environmental consequences of mine closure; the other is environmental terrorism. In principle it is not difficult to predict the pattern and rate of biodiversity recovery after mine closure on metalliferous depositional seabeds. 1-5 years to a self-sustaining community of organisms is a generalized guideline, depending on depth and particulate composition. The rate and pattern of biodiversity recovery on some metalliferous hard-rock habitats is far less predictable due to the patchiness and rareness of the habitat. Ecoterrorism at mines, whether on-land or marine, is now to be expected. A good example of resource industry ecoterrorism is the fire-bombing of logging and cement trucks in Oregon in 2001. But there have also been bombs at mine sites, as at Asbestos, Quebec. It is also possible to regard some resource-loss lawsuits as frivolous, hence forms of ecoharassment. Marine mining operations should take note of the development of environmental terrorism (and terrorism in general) and its various manifestations and impacts. Potentially these range from minor work stoppage inconveniences, to serious financial risk jeopardizing the economics of a mine, to jail for company executives, managers and environmental staff, and to harassment and killing of mine personnel.

Jan 1, 2005

By J. J. Bourquin

"The Keely mine at Dagger, Indiana, is one of the few mines that is being operated successfully on a cooperative basis. This shaft mine is developing 133 acres of coal in the Indiana No. 6 bed, which here averages 5-1/2 feet thick and. lies about 110 feet below the surface. Thirty seven (37) miners and twenty (20) company men or day man are employed, and the daily output is around 300 tons. Practically the entire production is sold by contract for railroad use. No mining machines are used and all coal is produced by pick work.The mine was originally owned and operated by the Stockton Coal. Co. of Dugger, but about eight years ago it was leased to Mr. Roy Price. He sub-leased the property to ten miners, who formed an association known as the Dugger Mutual Coal and Mining Co., to work the mine cooperatively.At first many difficulties were encountered; the cooperative idea is an old one, but the practice was new to those interested. Some of the men were energetic, ambitious workers; others were inclined to let their associates produce the coal but wanted to share in the profits. In time, after a hard struggle and many changes in the personnel of the company, business-like methods were adopted and the mine was put on a paying basis."

Feb 1, 1983

By Leonhard Weixler, Peter Platzek

The Company Bauer Maschinen is very well known in the field of specialist foundation equipment. In the diaphragm wall market, we have experiences both in manufacturing and executing projects all over the world since 1984. We have a population of more than 300 units working all over the world in all climate and soil conditions. Especially for hard soil and rock conditions, we have developed several cutting tools and systems to optimize the performance, e. g. the “flipper tooth” Besides the execution of land based foundation projects, we have performed our firs offshore project with the trench cutter in 1994. Our task was to take samples out of the alluvial soil off the coast of Namibia in a water depth of max. 200 m. We converted a drill vessel and launched the cutter thru the moon pool. The samples had a cross section of 3,40 m² and a max. depth of 5 m. They were used to estimate the content of diamonds. The first time, we reached the seabed of the deep sea was together with our seafloor exploration rig MeBo, where we can take cores up to a length of 160 m in a maximum water depth of 4000 m. With our customer MARUM, we have done several expeditions since 2005. The last expedition took place in the Black Sea to explore gas hydrates.

Jan 1, 2018

By Leonhard Weixler, Peter Platzek

The Company Bauer Maschinen is very well known in the field of specialist foundation equipment. In the diaphragm wall market, we have experiences both in manufacturing and executing projects all over the world since 1984. We have a population of more than 300 units working all over the world in all climate and soil conditions. Especially for hard soil and rock conditions, we have developed several cutting tools and systems to optimize the performance, e. g. the “flipper tooth” Besides the execution of land based foundation projects, we have performed our firs offshore project with the trench cutter in 1994. Our task was to take samples out of the alluvial soil off the coast of Namibia in a water depth of max. 200 m. We converted a drill vessel and launched the cutter thru the moon pool. The samples had a cross section of 3,40 m² and a max. depth of 5 m. They were used to estimate the content of diamonds. The first time, we reached the seabed of the deep sea was together with our seafloor exploration rig MeBo, where we can take cores up to a length of 160 m in a maximum water depth of 4000 m. With our customer MARUM, we have done several expeditions since 2005. The last expedition took place in the Black Sea to explore gas hydrates.

Jan 1, 2018

By D. D. Lauriski

The Mining Division of Utah Power and Light Company is located in the coal fields of southeastern Utah -main office in Huntington, Utah. The Division will produce 6.5 million tons of low sulfur steam coal in 1988, making UP&L the largest underground mining operation west of the Mississippi. Coal is mined from three underground mines utilizing continuous miner and longwall mining methods. All coal produced by the Mining Division is utilized at UP&L's two largest steam-electric power plants, the Hunter and Huntington plants with a combined capability of 1,995,000 Kw. At UP&L we believe that to achieve success a company must have clearly defined goals which are understood, communicated and shared at each level of operation. We have also found from experience that a safe operation is generally an efficient and productive operation. As a Division, we have established a goal to achieve the safest, most efficient operation in the country. This is an ambitious goal. To achieve such a goal requires real commitment and a safety/training program capable of achieving needed results. The following is an overview of the program we have established at UP&L which has enabled us to reduce our accident frequency rate from over 40 in 1980 to 8.00 at present, as illustrated in Figure 1.

Jan 1, 1989