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By J. Kelleher, R. Saulters, K. H. McDaniel, L. Griswold

To improve underground safety and visibility during mining applications, the Waste Isolation Pilot Plant designed and built a dry-dust filtration unit. The unit works in conjunction with a Spendrup 1120-70 fan with ventilation tubing to filter the face exhaust air during mining operations. The closed- loop system is designed to filter 17 m3/s (36,000 cfm) and is intended to screen 10- µm (1,250 mesh) and larger particles at 90% efficiency. To accomplish this, the unit uses a combination of Dollinger Staynew Inertial Spin filters, cyclones and traditional mesh filter media.

Jan 1, 2002

By L. W. Ashton

Geochemical exploration guidelines were developed from a study of 460 rock chip samples collected at nine disseminated gold deposits in Nevada. Obtaining high grade Au samples is difficult because gold content is extremely variable, even over 8 m (25 ft) distances. For reconnaissance sampling, pathfinder elements are reliable indicators with threshold values of 100 ppm As, 1 ppm Hg, and 50 ppm Sb. Arsenic is the most reliable of the three elements, being significantly enriched in all deposits. If the pathfinder threshold levels are reached with low Au content, more samples should be collected. Successful disseminated gold exploration requires large numbers of samples.

Jan 1, 1990

By R. N. Rothan, V. Khunova, C. M. Liauw, G. C. Lees

The interphase modification activity of 1,3-phenylene dimaleimide (also known as m-phenylene bismaleimide (BMI)) has been studied in composites based on magnesium hydroxide (60% w/w) and a polypropylene block copolymer (PPBC) that featured an ethylene-rich elastomeric impact modifier phase. BMI was found to be a unique product that led to significant simultaneous improvements in composite strength and toughness, even at the high filler levels. BMI modification was found to promote encapsulation of filler particles with the elastomeric phase of the PPBC together with formation of a PP boundary layer of increased crystalline content.

Jan 1, 2003

By Anthony T. Eyton

Intelligent Systems: Advantages for Mining ? Increased safety (reduced risk to workers) ? Increased productivity (reduced downtime) ? Reduced maintenance costs ? Customized solutions for different mines ? Growing acceptance among mine managers A Typical Precarn Project ? Meets definition of intelligent systems ? Involves at least two Precarn members ? a technology developer partner and a user partner ? in a true collaboration ? Involves at least one university and may have various other players ? Leads to a demonstrated prototype ? Costs $2-4 million, and lasts 12-30 months ? Gets up to 40% of its funding from Precarn (max. $1 m) ? Produces new intellectual property -- owned by the project team

May 1, 2002

Queensland hosts vast deposits of brown and black coal, significant accumulations ranging in age from Permian to early Tertiary. The great diversity of coal resources in the State to some extent reflects the proximity of Queensland to plate-marginal tectonic processes through much of the Phanerozoic eon. Coal is contained within sedimentary basin fills of four fundamental types; 1. extensional, 2. foreland, 3. strike-slip, and 4. intracratonic. Thick (10 m+) though laterally restricted coal bodies are characteristic of extensional and strike-slip basins, whereas coals of more modest thickness but much greater lateral extent are typical of foreland and intracratonic basins.

Jan 1, 1991

By Viney K. G, Molinia A. B

The Hellyer Pb-Zn-Ag orebody in western Tasmania was discovered in 1983, and mine production at a rate of 250 000 tonnes/yr commenced in 1987. Expansion to 1 million/yr will be completed by early 1989. Exploratory development to gain access to the orebody, to provide a 20 000 tonne bulk sample for pilot plant work and to confirm mining conditions and orebody continuity was undertaken using conventional drill and blast techniques and large diesel trackless equipment. A ventilation shaft was raisebored. Development in this phase totalled 2 815 m and provided a sound basis for rapid expansion of the mine.

Jan 1, 1988

AARONS, J. BOYD, Major. AGNEW, FRANK VANS. ALLEN, HERMAN H., Private, D Co., 8th -Reserve Engineers. BAINS, THOMAS M., Major, Engineer Officers' Reserve Corps. BANKS, H. R., Lieutenant, Canadian Engineers, B. E. F. BARBOUR, PERCY E., Deputy Supt. (Captain), New York State Troopers; Captain, 22d Regiment, N. Y. N. G. BARLING, H. B., Ist Lieutenant', Engineer Officers' Reserve Corps. BIGELOW, BRAXTON. BLOOMFIELD, E. C., Lieutenant. , BORROW, F. K. BROCK, R. W., Major, 19th Reserve Battalion of Canadians. BROOKS, ALFRED H., Captain, Engineer Officers' Reserve Corps. BROWNE, DE COURCY, 1st Lieutenant, Ordnance Dept., Fortress Monroe, Va.

Jan 9, 1917

By Takashi Sakaguchi, Takehiko Tsuruta, Akira Nakajima

Some attempts were made to recover gold from aqueous systems using immobilized persimmon tannin. This adsorbent adsorbed gold from solutions containing hydrogen tetrachloroaurate (III) with high efficiency, whereas there was minimal adsorption from solutions containing gold (I) sodium thiomalate and sodium dicyanoaurate (I). The adsorption of gold was rapid, and was affected by the pH of the solution, temperature, external gold concentration and amount of adsorbent. Adsorbed gold was easily desorbed with 1 M thiourea solution, indicating that immobilized persimmon tannin can be repeatedly re-used for the recovery of gold using adsorption-desorption cycles.

Jan 1, 1995

By Douglas A. Blankenship, Randall G. Stickney

The corejacking test is a field test designed to measure the response of salt to known boundary conditions. A 1.0-m-diameter salt core is externally pressurized using curved flatjacks placed in the annulus surrounding the core. Time-dependent deformation of the salt is measured by monitoring the diametrical closure of an inner borehole. A finite element elastic analysis of the jack loading system has been performed. The purpose of this analysis was to determine if the original assumption of axisymmetric loading is correct. Six loading cases were investigated, each representing either hypothetical or previously encountered jack configurations.

Jan 1, 1982

By Bradford NL

The Isa Mine of Mount Isa Mines Limited produces 5.1 million tonnes of copper ore and 2.2 million tonnes of silver-lead-zinc ore from sublevel open stopes annually. Extraction of the narrow, steeply dipping silver-lead-zinc orebodies requires a strategy quite different to that used in the massive copper orebodies. A range of blasthole diameters, explosive types and initiation systems gives the flexibility needed to adapt open stoping to a variety of situations. Hole diameters from 70 mm to 200 mm are being used, with lengths of up to 100 m common for the latter.

Jan 1, 1982

By F. R. Hensel

ACCORDING to statements by Guertler,1 Smith and Hamilton were the first to study the copper-titanium alloys, but owing to the presence of large amounts of impurities their data are inconclusive. M. A. Hunter and I. W. Bacon later investigated the electrical conductivity and the temperature coefficients at room temperature. The present writers reported their results2 in November, 1930. Recently Droll published data on copper-titanium alloys3 which agree closely with those obtained by the authors. MATERIAL TESTED The titanium used was in the form of square sintered rods, the analysis of which runs as follows: titanium, 95.4 per cent; silicon, 0.7; iron,1.8; aluminum, 1.4; copper, 0.1; manganese, 0.05. . The ingots were prepared in a high-frequency induction furnace in air atmosphere. Their analyses are given in Table 1. Up to 5 percent titanium the alloys could be forged. Above that amount they were red short and broke up easily. Owing to their rapid absorption of nitrogen and oxygen from the air, the alloys with the higher amounts of titanium tend to form surface films which greatly increase the casting difficulties, especially when small masses of metal are handled. It was, however, possible to prepare sound ingots up to 25 per cent titanium.

Jan 1, 1931

By K. E. Mantell

1. TRACKLESS MINING AT OAMITES by K. E. MANTELL Oamites Mine, brought into production in late 1971, is located 50 km south of Windhoek, South West Africa, on the northern boundary of and just outside the Rehoboth Gebied. Oamites was known as a possible mining proposition at the turn of the century when Hanseatische Minen Gesellschaft was adit mining on the adjacent farm Kamzwas. Rand Mines Limited carried out a small amount of prospecting in the early 1960s, Falconbridge Explorations Limited later taking over the prospect. Approximately 4600 m of diamond drilling was carried out between 1965 and 1967.

E. DEGOLYER,-New York, N. Y. (written discussion*).-Since the eastern part of the Gulf Coastal Plain is receiving considerable attention from various operators at the present time, it occurs to me that it brief review of most recent operations may be of interest in this connection, as well as a discussion of some of the points suggested by Mr. Hager. During the latter part of January, 1918, the Alahoma Oil Co. completed and abandoned a 3400-ft. (1036-m.) dry hole in Section 25, Township-8 North, Range 1 West. This well was drilled near the axis of the

Jan 4, 1918

By Rock M. Poulin, Bruce G. Moulton, Daniel E. Nowak, David T. Cass

The Yacambu Irrigation Tunnel Project of 34 km, 5 meter diameter circular and horseshoe section, has been under construction since the early 1970's. Notable among the excavation challenges is high ground cover of 3,000m creating large lithostatic pressures in the tunnel alignment with subsequent plastic flow of the ground in the tunnel walls. The tunnel may converge from small amounts to 1 or more meters of diameter over long sections. Several excavation techniques have been attempted but all without desired results. The paper proposes a new machine concept that uses the history of ground experience as its basis for design.

Jan 1, 1995

By Charles H. Arnold

This topic addresses historic and current techniques of excavating, supporting and lining tunnels of 4 m (13.1 ft) and smaller. Special considerations relate to the economics of working in close quarters and the sizes of tunnel which achieve the required facility in the optimum economic manner are discussed. The excavation discussion includes TBM, conventional and special techniques for hard rock, soft ground, subaqueous, free and compressed air tunnels. Internal and external support methods discusses timbering, steel ribs, bolting, strapping, shotcreting, grouting, and freezing. Lining methods include cast-in-place concrete, concrete pipe, segmented linings, shotcrete, and others.

Jan 1, 1981

By Kenneth R. Dickson, I. Michael Gowring, Gary M. Davey

The Kemano Power Tunnel is currently being constructed by a joint venture of Atkinson, Kiewit, and Commonwealth. The 5.73 m diameter, 16.1 km long tunnel is part of the Kemano Completion Project in British Columbia, Canada which is being developed by Alcan Smelters and Chemicals Limited. The discussion includes the refurbishment and development of Robbins TBM 189-229 previously used at Calaveras (RETC Proceedings, 1987), the logistics of conducting a tunneling operation in a remote area with adverse weather conditions, in addition to a description of the work and the performance details in the various geological conditions encountered to date.

Jan 1, 1991

By Deane Tunaley, Paul Tidman, Qian Liu, John Mullay

Laboratory studies have indicated that the crystallization and desensitization of microballoon sensitized emulsion explosives start immediately after shocking or pre-compression. However, the question of whether or not the shocked emulsion could be worsened by the growth of crystallization or recovered by rebounding back to lower densities has been rarely examined under actual rock blasting conditions. This study was primarily intended to investigate the desensitization characteristics of two commonly used emulsion products in terms of blasthole spacing and delay duration. In the experiment, two parallel blastholes, 32 mm in diameter and 1.7 m deep, were drilled downwards in an underground drift.

Jan 1, 1995

By D. M. Buck

D. M. Buck, * Pittsburg, Pa.-During the first 5 months of 1918, approximately 11,000,000 lb. per month of pig tin were consumed in the United States. Solder, hearing metals, bronzes, etc. used about 5,500,000 lb.; collapsible tubes a little more than 250,000 lb.; tin-foil about 500,000 lb.; and the tin- and terne-plate industry somewhat less than 5,000,000 lb. In an effort to reduce this consumption and thus conserve our tin supplies, several methods of procedure suggest themselves: 1. Salvage. The most careful and systematic collection and re-use

Jan 12, 1918

By R. G. Hudson, L. Yang

In electrochemical separation of metals, it is necessary to control the potential applied between the electrodes so that only the desired electrode reactions can occur. A knowledge of the minimum potential needed for a given electrode reaction to take place continuously is therefore pertinent to the success of the process. In molten chloride systems at high temperatures, activation polarization is believed to be small,1,2 so the minimum potential needed for the electrolytic decomposition of a molten metal chloride MC1n (n = valence of the metal ion) is therefore essentially the equilibrium electrode potential E of the metal-chlorine galvanic cell in the solution. If the decomposition products are pure M and chlorine at a pressure of p atm, E*Eo-rt/nf in [i] Since EO (the standard electrode potential of MCln) is a constant at a given temperature and R (the gas constant), and F (the Faraday's constant) are all constants, the variation of E with the electrolytic bath conditions is largely determined by the effect of the latter on the activity of the metal chloride amcln (standard state = pure MC1,). Measurement of E and study of how amCin varies with temperature and concentration, the nature of the solvent, and that of the coexisting solutes are therefore pertinent in the selection of optimum operating conditions for the electrochemical separation of metals. Because of its low melting point, high decomposition potentials of its components, and the low solubility of heavier metals in it, the LiC1-KC1 eutectic melt is a useful solvent and has been used in the electrodeposition of Mo,3Ce,4 and u5 metals. Senderoff and Brenner3 measured the potentials of Zn/Zn++, Fe/Fe++, Cu/Cu+, Mo/Mo+++, and Ag/Ag+ against an Ag/AgCl (pure) reference electrode at 600°C and a concentration of 4.1 mole pct of each chloride and came to the conclusion that complex ion formation occurred in some of the melts. Laitinen and LiUe gave an electromotive force series at 450°C for a number of {Metal/Metal ions (unit activity)) electrodes in LiC1-KC1 eutectic melt, the {pt/pt++ (unit activity)) electrode being chosen as the reference. Walker and Danly7 studied the ther-modynamic properties of NiC12 in LiC1-KC1 eutectic melt over a wide range of temperatures and concentrations by measuring the electrode potential between a nickel electrode and a chlorine electrode in the melt. Since potential measurements made by using the chlorine reference electrode are of more direct significance both in the study of electrochemical separation and in the evaluation of the thermodynamic properties of the melt, it is therefore decided to measure the electrode potentials of cells of the type {M/MCin (mole fraction = N) in LiC1-KC1 eutectic melt/Cl2 over a range of N values and temperature for a number of metal chlorides. The results should indicate the order by which the various metals plate out on the cathode and how this order is affected by temperature and the concentration of the metal chloride in the solu-

Jan 1, 1960

By Rafael A. Rivera

"Since the dawn of construction, there has been a need for excavations, which sometimes need to occur below the groundwater table. Excavations in themselves are difficult enough, with the myriad of requirements, such as engineered support of excavations, considerations for stability and numerous other concerns. Excavations executed in rural landscapes can be accomplished easily without significant consideration to accessibility, adjacent properties or structures, and construction limits and deformations. However, all of these factors can have an impact on excavation considerations in an urban landscape. When digging below the groundwater table, these conditions, along with concerns associated with groundwater drawdown requirements, discharge limitations, groundwater contamination, property limits, adjacent buildings and subsidence concerns, can lead an experienced dewatering contractor to consider diverse installation methodology and equipment to allow construction to occur below the groundwater table.534 W. 29th St. New York, N.Y.There are many things that must be considered when constructing a new high-rise building within a small property footprint measuring 25 ft (7.6 m) wide by 80 ft (24.4 m) in length. When you take into account that the foundation needs to go several feet below the groundwater table and that there are two existing multistory buildings with shallower foundations on either side of the proposed structure, this task now becomes much more difficult. Consideration of geology, groundwater levels, depths of excavation and shoring for the excavation becomes critical to the success of the project. On a regular basis, dewatering contractors confront similar situations in congested cities where available real estate is limited.To minimize the negative impacts of construction dewatering, it is important to mitigate the potential effects of construction dewatering to the surrounding buildings, sidewalks, underground structures, tunnels, subways and other existing infrastructure. Such an instance occurred at the project located at 534 W. 29 St. in New York City. On this particular project, the required drawdown was greater than the typical 15 ft (4.6 m) of suction lift, so a vacuumed can pump system was utilized. The tubing was connected to a vacuumed perimeter dewatering well-point system, which is a predrainage system that is installed prior to the start of excavation for the underpinning of the adjacent structures and for the overall foundation. Each well-point, which was composed of a PVC pipe that was 1.5 in (38 mm) in diameter by 25 ft (7.6 m) long, was drilled to a depth of about 23 ft (7 m) using a hollow stem auger and was installed around the perimeter at a centerto- center spacing of about 7.67 ft (2.3 m). In lieu of a traditional perimeter collection header, and to allow for greater flexibility for the contractor, the well-points were interconnected to a modified vacuum can pump system utilizing ¾ in (19 mm) drop tubes that were “spaghetti” around the perimeter."

Jan 1, 2017