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On. Tuesday, Apr. 8, the Rocky Mountain Club held its 12th annual dinner at the Waldorf-Astoria, New York. In reporting the dinner the Evening Telegram says: "General Coleman du Pont was sort of master of ceremonies, and he conducted the affair at the end of a Colt .45. It was the General's `forty-five' which filled the banquet hall of the Waldorf-Astoria with the brand of smoke which Uncle Sam showered so generously upon Germany's hordes. It was General du Pont's `forty-five' which bellowed and thundered and echoed through Fifth avenue, scaring horses and shell shocking pedestrians: But no one was hurt or badly shocked except those who could not discern the artistry of Miss Doraldino's dance. "There were Western men around the table who have just come hack from over there. For instance, there were Brigadier General G. H. McManus, General Shanks and a score of others. And there were Thomas H. Watkins, who is said to own half the State of Pennsylvania and is known as the `Coal Baron'-of Pennsylvania,, and Alba B. Johnson, president of the Baldwin Locomotive Works, each one a Westerner, with personality and type suggestive of some of the wonderful men Bret Harte wrote so much about. "It seemed as though General du Pont, who was chairman of the Reception Committee, tried to eclipse all former meetings, and he succeeded if congratulations are a criterion. " General du Pont startled the management of the Waldorf and surprised the diners by staging a three-round bout between Frankie Fay and Phil Wagner. The clash between these two featherweights made Waldorf history, because it was the first boxing contest ever held in the hotel. Tex Rickard, who is going to chaperone Jess Willard and Jack Dempsey in a fight in the near future,-was scheduled to referee the contest, but at the last moment, for some obvious reason, M. E. Schermerhorn was sent in as third man. The bout was a slashing one. Miss Amparito Farrar, lately returned from France, where-she sang for the 'dough-boys;' Eleanore Wetmore, the Rath Brothers and Phil Baker were among the others who entertained.

Jan 5, 1919

By D. J. Young

Alloys used at high temperature must resist both creep and corrosion. Design for corrosion resistance is based on the formation of a slow-growing, protective oxide scale by selective oxidation of an appropriate alloy component, usually chromium or aluminium. A successful scale will exclude other corrodents, notably carbon, which can otherwise cause extremely rapid corrosion at high temperatures. Selective oxidation of an alloy component necessarily lowers the concentration of that metal in the alloy subsurface region. Under thermal cycling conditions, mechanical damage to the scale leads to renewed oxide growth and accelerated alloy depletion. Eventually, a point is reached where diffusion of a corrodent into the alloy becomes competitive with the outward diffusion of alloy metal to repair the protective scale. Two examples of alloy failure by carbon attack are considered. In the steam cracking (pyrolysis) process, centrifugally cast tubes of heat-resisting alloy are exposed to a gas stream of hydrocarbon and steam, at a carbon activity of unity. Formation and repair of the surface chromia scale causes alloy depletion, Kirkendall void formation, and subsequent internal precipitation of chromium-rich carbides. Their formation makes chromia scale formation much more difficult, and generates internal stress. Eventually, the tubes fail by creep rupture. In other processes (e.g. steam reforming, heat treatment), synthesis gases are supersaturated with carbon at intermediate temperatures. Once the alloy's protective scale is breached, carbon attacks the depleted substrate. In the case of ferritic alloys, it forms a surface scale of Fe3C. As this scale thickens, the supersaturated carbon precipitates as graphite within its outer regions. The resulting volume expansion causes disintegration of the cementite in a process known as metal dusting. In the case of austenitic alloys, no metal carbide is formed. Instead, carbon dissolves in the depleted metal to diffuse inward and precipitate as graphite within the metal matrix. Again, volume expansion causes disintegration of the alloy, and metal dusting results. Dusting occurs at an extraordinarily rapid rate, and leads to failure by section loss or even penetration.

Jan 1, 2013

By C. D. Thompson

Pile load test programs were carried out in 1984 and 1985 at Stelco's and Dofasco's Steel Making Plants in the Hamilton Bayfront area. 323.9 mm outside diameter by 9.5 mm wall thickness Grade 3 steel closed-end pipe piles were driven to practical refusal at depths of 21 to 30 m in very dense silt till with Delmag D30 open-end diesel hammers. Ultimate bearing capacities of up to 5330 kN were proved by dynamic monitoring and static load tests. Allowable bearing capacities of 1780 kN were achievable on production piles without undue difficulty. It was found that the impact stress at the top of the pile was controlled by the yield strength of the steel rather than a useable upper limit based on the modulus of elasticity. A bearing to impact stress ratio of 1.2 at practical refusal was observed to be reasonable but conservative at this site, and is felt to be generally applicable for piles driven to practical refusal elsewhere. Dynamic monitoring during production pile driving was able to show that apparent relaxation was caused by pre-ignition of the hammer when visual observations indicated that pile driving was proceeding satisfactorily.

Jan 1, 1987

By L. W. Bahney

Many methods for the determination of gold or silver, or both, in cyanide solutions have been published, which with care in manipulation, and modification in some cases, will give results that are satisfactory. It is possible to classify or group these methods as follows: 1. Evaporating the solution in a porcelain or agate-ware dish containing litharge,l or in a "boat" made of lead foil. 2. Forming a lead sponge containing the precious metals by means of zinc shavings,2 zinc dust,3 or a piece of aluminum.4 3. Decomposing the cyanide solution with an acid and precipitating the precious metals by the use of one or a combination of some of the following: Copper sulphate,5 sodium sulphite,6 hydrogen sulphide,' cement copper.ll 4. Precipitating the silver by zinc dust held in a Gooch crucible and determination with a standard solution of sulphocyanate.9 5. Electrolysis.l0 . 6. Colorimetry.ll

Jan 1, 1915

By R. G. Kidel, S. C. Doming

The project has shown that it is feasible for a junior company to reopen a narrow vein-style gold mine and successfully take it into production. An intimate understanding of the mineralisation and a flexible approach to mining are crucial, as are stringent cost control and efforts to keep overheads low. The project has confirmed the geological complexity of the Main Lodes, which consist of highly sheared quartz-sulphide infill in strongly sericitised granodiorite. The existence of discrete high-grade zones within the Hangingwall Lodes has also been confirmed. Broad low-grade zones continue to be recognised and require the local application of bulk longhole mining methods. The initial mine plan called for predominantly longhole stoping, but adverse ground conditions have meant that a switch to air-leg mining has produced higher run-of-mine grades. The excess capacity at the processing plant can best be used by batch processing, with its reduced maintenance requirements

Jun 21, 1905

By Lv Guozhi, Ren Xiaodong, Liu Yan, Dou Zhihe

"This paper investigated a new desulfurizer, dolomite and ferrosilicon. Magnesium vapor produced by silicothermic reduction of dolomite and ferrosilicon in an immersion tube of molten iron was injected into the molten iron by carrier gas through the underpunch of the tube and desulfurization reaction occurred. In order to explore the desulfurization process of molten iron by the new desulfurizer, the thermodynamics, and experiments of magnesium vapor production and desulfurization have been studied. Through thermodynamic calculation, the reaction temperature of magnesium vapor production by 75ferrosilicon and light-burned dolomite is 1838K in the standard state and decreased with the decreasing partial pressure of magnesium vapor, PMg· When PMg=25kPa, the reaction happens at 1673K. From experiments of magnesium vapor production, reduction efficiency of Mg vapor is about 60 % in 15 minutes at 1673K. From hot metal experiments, the desulfurization efficiency is 89.35%, and the lowest sulfur concentration after desulfurization is 46ppm.IntroductionPretreatment desulfurization of hot metal has become a necessary step in modem optimizing steelmaking process for its cheap cost, which can not only liberate of blast furnace productivity and reduce the burden of produce steel, but also effectively improve overall economic efficiency of the iron and steel system[l-ZJ_ At present, injection magnesium particle is one of the two main methods of desulphurization in hot metal owing to its strong affinity for sulphur, low amount of slag produced, low iron loss in slag skimming and low equipment investment[3l. However, there are still some insufficiencies on the hot iron pretreatment with magnesium particles at present[4-5l"

Jan 1, 2013

By T. E. Wakefield

Over several decades in Southern Africa the advance rates when sinking vertical shafts have declined significantly. The upside has been a substantial improvement in shaft bottom conditions and a commensurately improved safety performance, with an increasing number of shafts being sunk without fatalities and disabling injuries. This paper briefly reviews historical sinking rates and matches changed sinking productivity to the introduction of new sinking methods that have been adopted to eliminate/mitigate safety risks. Meeting the challenge of returning to historical advance rates whilst progressing in the quest for zero harm by utilizing three dimensional animated computer modelling is described. Making use of commercial modelling software makes it easier to evaluate different methods, sequencing, in shaft barrel ergonomics, and stage and shaft bottom layouts before procuring project plant and equipment. Benefits accrue not only in better communicating methods and configurations for detailed planning and design, but also during crew training. The traditional engineering ?as-built? drawing practice has been extended to the concept of an ?as executed? sinking model which seeks to capture operational experience and learning for future best practice. The paper concludes with some of the organizational culture challenges being overcome as this non traditional approach to shaft sinking optimization is being introduced.

Jan 1, 2009

By M. C. Irani

This Bureau of Mines report tabulates methane emissions from U.S. bituminous coal mines with daily emission rates of at least 100,000 cfd according to States, counties, and coalbeds. Most of the methane emitted is from mines in the Appalachian States. Total daily emission in 1975 was 216.3 MMcfd, compared with 227.0 MMcfd in 1971 and 214.5 MMcfd in 1973. Thirty counties in nine States hid daily methane emissions of 1 MMcfd or more. These emitted 93 percent of the total methane. The highest emissions were from Monongalia County, W. Va., which accounted for 18.9 percent of the total. This was followed by Marion County, W. Va., 9.6 percent; Buchanan County, Va., 8.3 percent; Jefferson County, Ala., 6.1 percent; and Washington County, Pa., 5.9 percent. The Pittsburgh coalbed emitted 45.7 percent of the total methane, followed by the Pocahontas No. 3 coalbed with 12.9 percent. The report lists 196 mines, of which 60 had daily methane emissions of 1 MMcfd or more. Included in this compilation are the identification and thickness of the coalbed, methane emission, coal production and ventilation rates, number of drifts, shafts, and slopes used for ventilation purposes, shaft depth, age of mine, and gas-to-coal ratio.

Jan 1, 1977

ALABAMA Aldrich.-Lloyd, T. W. Ashland.-Downs, F. G. Geary, E. S. Auburn.-Brown, R. L. Bessemer.-Abbott, C. E. Ball, T. L. Ferguson, V. Salmon, H. S. Stuart. Q. W. Birmingham.-Adams, J. H. Aldrich, T. H. Aldrich, T. H., Jr. Allen, A. W. Armstrong, W. D. Ball, E. M. Bonnyman, J. Bush, M. W. Crawford, G. G. Davis, C. B. Ellis. E. E.

Jan 1, 1923

By F. W. Wood

The use of consumable.-electrode arc melting as a production technology is growing. One advantageous feature of this process is that it avoids ingot contamination by soluble crucible materials by employing a chilled metal crucible. Because the thermal balance under these conditions is rather delicate and does not necessarily provide a favorable environment for solidification, catastrophic imbalances can occur. The effectiveness and mechanistic roles of various factors are mostly unknown, and more intelligent insight regarding the distribution of temperature and heat is needed. Experience has provided several pertinent observations, some of which are quite superficial. The most meaningful data have resulted from studies of molten pool shapes and sizes and from measurements of heat flow through crucible walls. Overall experience, intuitively interpreted and supplemented, is sufficient nevertheless as a basis for a boundary-value treatment of the problem. A mathematical analysis based on a separation of variables, using conventional differential equation methods, provides a useful solution. For a cylindrical ingot, the temperature varies as a Bessel function of an argument proportional to the radius and as an exponential function of longitudinal position. Trial calculations using the problem solution seem to verify the general correctness of the result as compared with experience. The role and nature of solution parameters are also clarified, though not entirely resolved. It is revealed that the barrier to heat flow at the ingot-crucible surface has a prominent influence. Utility of the model embodied in the problem solution is readily demonstrated by considering a variety of contemporary questions about arc melting, and it is hoped that utility can be enhanced by improvement of the model.

Jan 1, 1968

By Jim Bruce

The Transformation AGO project, constructed between 2005 and 2008, featured a foundation trade contract that included design of pile caps and grade beams and construction of 138 permanent micropiles. The new foundation works were constructed within seven different settings ? each featuring a host of attributes challenging to constructability ? inside and outside the existing Art Gallery of Ontario, all while the gallery remained open for business. Transformation AGO resulted in several firsts for micropiles in the Toronto construction market: this was the first micropile trade contract with a multimillion dollar contract value; it featured the first static compressive load test performed beyond 7000 kN on a single micropile; the first static compressive load test beyond 8000 kN on an experimental pile cap supported by two test micropiles; and it was the first publicly funded project to go to tender with micropiles listed as the preferred foundation option. This paper outlines the successful application of micropiles at the landmark Transformation AGO project.

Jan 1, 2011

By V. B. Achanti, A. W. Khair

Laboratory studies were carried out at West Virginia University to investigate the rock fragmentation mechanism by continuous miners using an automated rotary cutting simulator. The primary factors influencing the fragmentation process were found to be: bit spacing, bit geometry, depth of cut and cutting drum rotational speed. This paper presents the influence of these parameters in achieving optimum energy consumption and minimizing dust generation during rock fragmentation process. Tree bits were used simultaneously on Indiana limestone while the bit tip angle was varied from 60° to 900. Bit spacing was varied from 2.54 cm (1 in.) to 5.08 cm (2 in.) while the cutting process was assessed for varying cutting depths. Restorable dust generated during the course of the experiments was analyzed utilizing cascade impactors. Assessment of these parameters has led to a better understanding of the cutting mechanism by continuous miners in terms of energy consumption and dust generation.

Feb 24, 1997

Coal cleat and faulting influence failure, gas release, and choice of preferred mining directions, locations, and sequences. Unfortunately soil and younger rock cover restrict direct mapping of these structures ahead of mining operations. Aerial photographs of cover contain indirect indications of concealed structures in arrays of linear photostructures. These arrays are commonly too complex for interpretation by simple visual inspection.Analytical techniques applicable to complex arrays are illustrated for a covered part of the Galilee Coal Basin, Queensland. These techniques are: optical determination of sets in arrays of photostructures; correlation of these sets with sub-surface structures; filtering of m-rays for particular sets; detection of anomalies associated with concealed structures in the density distributions of particular sets; fitting filtered arrays to trajectories; correlation of trajectories with the regional directional variations of concealed structures; contouring of ratios of sets to discriminate anomalies associated with concealed fractures and variations in the total and bed thicknesses of cover; kinematic and dynamic inference on the basis of fracture-trace angular and spatial relationships.

Jan 1, 1979

The Zeehan field has yielded over 190 000 tons of lead and 26,000,000 oz of silver. Moh of the production took place between the initial discovery of silver-lead ore in 1882 and 1920, and the greatest part was extracted from fissure lodes in the Proterozoic to (?) lower Cambrian rocks. It is demonstrated that the prosperity of the mines relied upon the silver content, which is apparently highest in these beds, particularly where spilitic rocks are associated with them. In contrast, galena occurring in orebodies emplaced in the Gordon Limestone is low in silver.Most of the workings are relatively shallow due in some cases to enrichment related to erosion surfaces.Fault zones within a complex anticlinal structure exposing the Proterozoic to (?) lower Cambrian formations appear to have been major factors in the control of mineralization.

Jan 1, 1968

By S. L. R. Lenharo, H. Kahn, H. Born

Different ore types result from the irregular spatial distribution of the associated alkaline/carbonatite rocks and the zoned alteration profile within which apatite may have undergone reprecipitation. Different flotation responses are caused by their mineralogy, iron oxide impregnation and grain-size characteristics. Samples from seven deposits were crushed, screened and separated before being studied by chemical analysis, optical microscopy, X-ray diffraction, FTIR spectroscopy, cathodoluminescence and scanning electron microscopy. Two main apatite varieties with peculiar crystal morphology were identified: hydroxy-fluorapatite as the primary phase and carbonate-fluorapatite as the reprecipitated phase. The former occurs as prismatic or ovoid grains and the latter as polycrystalline aggregates or crusts on the primary grains; both are associated with iron oxide coatings (primary) or intergrowths (secondary). Microflotation tests showed variations in flotability for particular apatite associations as well as intensity of iron oxide coatings. The differences in flotation behaviour can be related to morphological properties and chemical substitution in the apatite structure

Aug 1, 1996

By J. B. Hiskey

Introduction The domestic copper industry has suffered for some time from declining ore grades; rising costs associated with conventional mining, milling, smelting and refining; tightening environmental restrictions; and shrinking markets due to materials substitution. Ore grade depletion is a major problem. It is illustrated by the decline in average copper yield shown in Fig. 1. From 1979, copper grade has dropped 60%, lowering yields from 1.2% to 0.49% (Sousa, 1981). The US copper industry is taking drastic measures to enhance its competitive posture and to guarantee its future worldwide position. In a sense, this involves a general restructuring of the processing philosophy of US copper producers. Judging from recent trends, this restructuring relates to the application of solution mining techniques to the treatment of copper ores and low grade waste material. Recovering copper by leaching techniques has been practiced for centuries. As early as the mid-16th century, some Hungarian copper mines were recycling copper bearing leach solutions through waste heaps (Nash, 1912). In the US, recovering copper from dilute mine waters has been carried out for more than 100 years. There are, however, certain technical innovations that have elevated the importance of solution mining as a process for copper recovery. These include: • Advances in solvent extract-electrowinning (SX-EW); • Developments in acid and acid ferric cure processes for oxide and mixed oxide sulfide ores; • Improvements in heap and dump construction; and • Advances in in situ leaching technology. Generally, solution mining enjoys certain intrinsic advantages over conventional mining and milling. Compared to conventional milling, the combined capital and operating costs of leaching facilities are normally lower, start-up times are faster, and the leaching operation usually has less impact on the environment. Furthermore, solution mining represents an expedient way of extracting metals from small shallow deposits, and is particularly suited to the treatment of low grade sources. And, in the case of waste dump leaching, there is a tremendous resource in-place that has the mining cost already off the books. This paper updates current US copper solution mining trends. Solution mining systems Schlitt (1980) summarized the characteristics of the principle leach systems in the US. He pointed out that the wide variations in copper deposits make solution mining a more site-specific activity than conventional mining and milling. Heap leaching is usually selected for moderate to high grade ores having a copper mineralization that is amenable to acid leaching (oxides, silicates and certain sulfides). Higher grade ores mined specifically for heap leaching are usually treated to optimize copper extraction, therefore, crushing and some pretreatment (acid curing) may be justified. On the other hand, dump leaching practice usually involves leaching low grade waste rock placed on large dumps as dictated by topography and haulage costs. Mine waste is therefore treated in an uncrushed run-of-mine condition. Finally, in situ leaching is appropriate for either very deep ore bodies or for recovering copper from low grade rock left behind in abandoned pit walls, stopes, and subsidence zones from earlier mining activities. True in-situ solution mining should be defined as the leaching of ore in its original geologic setting. Heap leaching Heap leaching has a long history as a hydrometallurgical process for copper recovery. The methodology of heap leaching established at Rio Tinto in Spain more than 300 years ago is basically the same as that used today. Processing concepts, such as solution management (sprinklers and leach/rest cycles) and copper

Jan 11, 1986

By D. Laguitton, D. Hodouin, V. K. Gupta, R. Spring

"The CANMET SPOC project aims at inducing progress in process evaluation and optimization by developing user oriented software based on state-of-the-art theory. The present work is the result of a joint effort by CANMET, Noranda Mines and Université Laval to develop two computer packages: one (RTD) to calculate the residence time distribution that best describes the material transport through the mill, the other (FINDBS) to estimate the rate of breakage and distribution function of the population balance model in a ball mill. The RTD package can handle data from various experimental methods (impulse or complex tracer feed, with or without recycling, etc...). The FINDBS package provides options for the functional description oj both model parameters Band S. The full detail of the methods and programs appears in a users guide. The program capabilities and several sample runs are presented.IntroductionSimulation of mineral dressing operations by computer has been largely contained within academic and research circles and has not yet gained a status of routine practice in the ore and coal industries. It is however a matter of time before process simulators are available on every process engineer's desk to assist process optimization tasks, flowsheet design and professional training. The CANMET SPOC project (Simulated Processing of Ore and Coal) was initiated in 1980 to assist the Canadian industry in integrating computer-based methodology for process evaluation and optimization(1). Software development, documentation and transfer is one of the main priorities of the project which will mature in 1985 by releasing a complete package of manuals and programs covering sampling, material balance computation, unit modelling, flowsheet simulation and optimization . This paper is a condensed description of a typical project element in its 1982-1983 state of development. The required methodology for ball-mill modelling and simulation was consolidated an d merged to other project elements during a joint study under contract financed by CANMET and Noranda Mines Ltd . The first part of the study dealt with documenting experimental methods and software for ball-mill computer simulation. Université Laval GRAAIM (Goupe de Recherche en Automatistion Appliquée à l'Industrie Minérale) acted as sub-contractor for this part of the study(16,17). A second part dealt with applying the model calibration techniques to a large industrial data base and is reported elsewhere(2,18,19)."

Jan 1, 1984

By Thomas A. Simpson

Traveling through the moors and valleys of Cornwall, England, one is reminded of the extensive mining activities of the past. Abandoned shafts, remains of granite block wheel houses and engine houses, battered brick stacks, old calciners, overgrown water wheel pits, count house remains, overgrown waste pits, and old portals are gaunt monuments to a once flourishing mining industry. Cornwall is bordered on the north by Devon and occupies the south-western most tip of Great Britain. The Atlantic Ocean borders the promontory; to the north, the mouth of the famous Bristol Channel faces the open sea; and to the south, the English Channel separates the land masses of Great Britain and Europe. This part of England is probably the most extensively mined ground in all of Europe. Such great mines as Dolcoath and Wheel Vor, Consols and South Carodan, Levant and Bottalack, remain legendary in the annals of metal mining in the nineteenth century. Many US mining districts hold close ties with Cornwall, Devon, and Wales through ancestors who emigrated from there to work in US mines in the eighteenth and early nineteenth centuries. Their descendants can be found in many major US mining districts, and their terms, expressions, customs, and methods have left an impact on the US mining scene that remains with us today.

Jan 9, 1981

By Peter Swanson

A seismic monitoring network has been installed in western Colorado (USA) in the vicinity of three underground coal mines to (i) distinguish and characterize seismic activity as either mining related or naturally occurring, (ii) implement a real-time event monitoring and notification tool, and (iii) collect data for use in research studies aimed at quantifying impacts from mining-related and natural seismicity. These potential impacts include dynamic rock mass failures such as coal bumps as well as strong shaking in the vicinity of critical structures such as impoundment dams, reservoirs, mine seals, mine openings, and steep slopes. Examples of two damaging seismic events are presented and the mining and geologic factors attending these dynamic failures are described.

Jan 1, 2008

By P E. H Gregg, R B. Stewart

Restoration trials established in 1985 included a treatment where pasture seed was sown directly into fertilised tailings. After seven years, accumulated soil data was used to compare physical and chemical changes in the plots with the original tailings control area nearby.   A known amount of annual fertiliser additions over the seven year period allowed nutrient balances to be calculated. Losses of S and P were relatively high at 72% of applied S and 28% of applied P. Calculations show that at least 240 kg N/ha/yr was fixed by clovers and this is likely to be under-estimated given that the calculation did not allow for leaching losses.

Jan 1, 1993