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By Claus Becker

At the RETC 1979 in Atlanta/Georgia it was reported about the beginnings of the Hydroshield system and the first site experiences. Since that time over 10 miles of tunnels in various diameters have been built with that system, and the discussion of the two most interesting projects will be the main topics of this paper. AURELIA TUNNEL, ROME In Rome, the railway system is going to be completed and modernized. Therefore, it is necessary to tunnel through the Roman hills. Part of the new railway system is the Aurelia Tunnel, located some 100 feet below the famous Via Aurelia Antigua, close to the Vatican. The double track railway tunnel has an internal diameter of 9.44 m and a length of 2.410 m. It runs through completely differing soil conditions. (Fig. 1) The first 1000 t are situated in watertight clay, the rear part in water bearing loamy, clayey sands with interlayers of loamy clays. The figure shows the soft change-over from clay to sand. The groundwater head is between [ ]

Jan 1, 1983

By Monica Pavlik, Thomas Wildeman

Water from the Forest Queen mine adit near Silverton, Colorado drains into a natural wetland. Because the pH of the water averages 5 and the iron concentration averages 18 mg/L, it was thought that the wetland might naturally treat the water. Of most concern with respect to the aquatic environment is zinc whose concentration averages 0.60 mg/L. Starting in October 1997, the surface waters, ground waters in the peat substrate, and the sediments in the wetland were sampled and analyzed four times over the course of four months. The adit water primarily remains as surface water where Fe, minor amounts of Al, and no Zn are removed. After the adit water enters the peat, then it is found that the pH rises to 5.8-6.5 and sulfate is reduced. The removal of Zn and A1 is caused by these two changes. However, Fe in its reduced state is quite soluble and may be remobilized in the reduced environment of the peat.

Jan 1, 2000

By Kenneth S. Johnson

Oklahoma is a region of complex geology where a mobile belt of Paleozoic geosynclines and uplifts on the south abuts against the margin of the North American craton to the north. The state contains many classic areas where fundamental concepts of sedimentation, stratigraphy, structural geology, historical geology, mineral investigation, and petroleum exploration have been formulated through the years. In the southern Oklahoma mountain belts, there are exposed a great variety of igneous and sedimentary rock units seen at few other places in the Midcontinent area. Major geologic provinces of Oklahoma (Fig. 1) include: (1) the cratonic and relatively stable northern shelf areas, including the Ozark uplift; (2) the Ouachita geosyncline (now the Ouachita Mountain belt) and associated Arkoma basin in the southeast; and (3) the southern Oklahoma aulacogen (geosyncline), comprising the area of Anadarko, Ardmore, Marietta, and Hollis basins, as well as the Arbuckle and Wichita Mountain uplifts. The three principal fold belts, the Ouachitas, Arbuckles, and Wichitas, all originated from a series of Pennsylvanian orogenies (about 300 million years ago) in the two Paleozoic geosynclines.

Jan 1, 1999

By Donald E. Stump

Subsidence from underground coal mining alters surface water discharge and availability. The magnitude and areal extent of these impacts are dependent on many factors, including the amount of subsidence, topography, geology, climate, surface water - ground water interactions, and fractures in the overburden. These alterations may have positive and/or negative impacts. One of the most significant surface water impacts occurred in July 1957 near West Pittston, Pennsylvania. Subsidence in the Knox Mine under the Coxton Yards of the Lehigh Valley Railroad allowed pan of the discharge in the Susquehanna River to flow into the mine and create a crater 200 feet in diameter and 300 feet deep. Fourteen railroad gondola cars fell into the hole which was eventually filled with rock, sand, and gravel. Other surface water impacts from subsidence may include the loss of water to the ground water system, the gaining of water from the ground water system, the creation of flooded subsidence troughs, the increasing of impoundment storage capacity, the relocation of water sources (springs), and the alteration of surface drainage patterns.

Jan 1, 1986

The processing capability of a semi-autogenous (SAG) mill is greatly affected by ore geology and operating variables within the mill. The SAG mill is problematic because it cannot be conveniently studied on a smaller, laboratory-scale mill. The interior of the mill, where grinding takes place, cannot be observed using instrumentation available today. Yet the motion of the rock and ball charge determines the power draft and hence capacity of the mill. Therefore, mill optimization is pursued with a charge motion simulation software. This software uses the discrete element method to describe the individual motion of numerous ball and rock particles in the mill. It is shown that by simply increasing the chord length between the lifters and increasing the face angle of the lifters the capacity of the mill can be increased. Such a configuration of lifters allows the operator to increase mill speed, hence drawing higher power while considerably minimizing direct ball strikes against shell plates and lifters. A case study of a 36 ft. diameter x 15 ft. long mill is presented. Reducing the direct ball strikes leads to lesser steel consumption both in terms of balls and lifters.

Jan 1, 2000

By Qing Wang

Open pit mines require substantial capital investment at the beginning of the operation and replacement investment at later years. The objective of obtaining the highest possible return on investment in a mining project can only be achieved with an efficient long term production plan. This plan consists of optimally determining four principal elements: 1) the amount of ore and waste to be mined each year, 2) the specific blocks to be mined each year, 3) the optimum mine life, and 4) the ultimate pit limits, which delineate the total reserve to be mined. The existing methodologies only provide solutions to one or two elements, by assuming the others known. Furthermore, the cost of mining each block in the deposit is assumed to be known and independent of the production schedule. The four elements of production planning are interrelated and the cost of mining any block is a function of the production schedule. The ultimate goal of this study, ,whose first steps are' discussed in this paper, is to develop a solution methodology that can simultaneously optimize all four elements of the production planning problem in open pit mines without making a priori assumption on any of the four elements.

Jan 1, 1992

By T. van Sandwijk, G. Van Weert, E. Molleman

This paper reports on test work that explored the dissolution/precipitation reaction: ZnS + 2HCl - ZnC12 + H2S, which is part of a process used in the production of pure ZnS. The research focused on the influence of proton activity on the dissolution of zinc concentrates obtained from the Brunswick Mine No. 12 in Canada (Brunswick Mining & Smelting); the Red Dog deposit in Alaska (Cominco Ltd.); and the Tara deposit in Ireland (Outukumpu Zinc). A comparison between the results of the experimental dissolution as a function of pH and the dissolution predicted by thermodynamics suggest that the three concentrates contained sig¬nificant amounts of the more reactive mineral wurtzite, although XRD analysis showed mainly the presence of the mineral sphalerite.

Jan 1, 1999

By R. Velkova, D. Bojinova

The objective of the present investigations is to establish the effect of the preliminary mechanical activation of phosphates on the degree of phosphorus extraction by bioconversion of Bulgarian and Tunisian phosphates using A. niger fungi and T: thiooxidans microorganisms. The influence of the phosphate concentrations, the type of the nutritive medium and the incubation times on the process of biological mobilization of the phosphates was studied. When the concentration of phosphates in the medium is twice as high, an equal and/or higher degree of phosphorus extraction can be achieved through the bioconversion of mechanically activated phosphates compared with non- activated phosphates under similar conditions. A maximum degree of 90+% phosphorus extraction in utilizable form was achieved at definite conditions.

Jan 1, 2002

By John K. Hollmann

The use of the direct method of determining coal methane content has grown in the last decade from a research technique into a practical coal exploration tool. However, the literature available on the subject is somewhat lacking in site-specific guidance and observations on the conduct of the method and the use of the resulting data. This study discusses some practical lessons learned in conducting a large scale direct measurement project at an operating mine, describes the initia1 interpretations and uses of data from the project, and presents observations from subsequent mine operations into the success and limitations of using direct measurement data in mine planning. The site studied is in central Pennsylvania on the Appalachian Plateau and includes coal seams in the Allegheny series.

Jan 1, 1987

By R. E. Johnson, L. V. Araújo, B. R. Palmer, L. M. Abrantes, G. W. Warren

The behaviour of chalcopyrite - mineral specimens and a Portuguese concentrate - in 2M chloride solutions prepared from hydrochloric acid and sodium chloride, has been characterized by cyclic voltammetry. The study has shown the influence of the potential and of the presence of impurities in the reaction schemes and their relative extent. The dissolution of chalcopyrite concentrate under potentiostatic control has been investigated and found to confirm the effect of the selected potential on the surface modification/rate of dissolution. An attempt has been made to correlate the information obtained with the response of the concentrate electrode to constant current treatments.

Jan 1, 1993

By John R. Woodcock

The Kitsault molybdenum deposit lies along the east margin of thecoast Batholith Complex near the head of the fiord of Alice Arm. It is 800 km (497 miles) northwest of Vancouver, British Columbia. The deposit is located on Lime Creek 8 km (5 miles) from the coast on a wide dissected upland valley at an elevation of 600 m (1969 ft). It is an area of coastal rain forest with high annual precipitation and extremely high winter snowfall. Although the area is of high relief, outcrops are largely restricted to ridges and canyons. Most of the area is covered by the coastal vegetation or wet swampy upland areas. The south edge of the molybdenum deposit was exposed in a sharp canyon; however, outcrops over the remainder of the deposit were largely restricted to a few small exposures of resistant hornfels. The mineralization is related to an elliptical porphyry stock of 52.3 m.y. age which intrudes argillites and microgreywackes of the Late Jurassic Bowser Group. A circular zone of alteration, with a diameter of about 700 m (2297 ft), occurs in the north end of the stock and the molybdenite mineralization is concentrated in the outer parts of this zone of alteration. Thus, the northern part of the mineralization occurs partly in the hornfels and partly in the stock, whereas the southern side of the ring of mineralization cuts across the middle of the stock. Zoning within this system includes a central circular area of almost complete replacement of quartz plus K- feldspar and this grades sharply outward into a phyllic zone. Clay alteration is largely localized along late faults. The ring of molybdenite mineralization is partly overlapped and partly surrounded by a zone of pyrite mineralization. Some chalcopyrite is coextensive with the pyrite zone. Late polymetallic veins fill two conjugate fracture sets. These quartz veins contain galena, pyrite, some chalcopyrite, and a number of lead-bismuth sulfosalts.

Jan 1, 1991

By John C. Wangaard

A method of raising by use of a cage has been used with considerable success at the Cary Mine, Hurley, Wisconsin, on the Gogebic Range. The Cary Mine is owned by the Odanah Iron Company, Pickands, Mather and Company, Managers. This method is known to have been used previously at Tennessee Copper and probably in other districts. The Cary Mine was engaged in deepening the main shaft from the 34th to the 37th level. To accomplish this, and to facilitate development, a ventilation shaft 930 feet north of the main shaft was sunk from the 34th to the 37th level and crosscuts were driven on the 35th, 36th and 37th levels to the main shaft location, These levels are at 200 foot verticalintervals. All of this work was done in granite and the majority of the workings were not timbered. The next step was to get a raise through from the 37th to the 36th level, and from the 36th to the 35th level, which would later be stripped to full shaft size. Several methods of raising were considered including double-compartment cribbed and two single raises interconnected at regular intervals, but the cage method was chosen as it appeared to be a safe and efficient operation. The method in general consists in the use of a drill hole between levels through which to pass a hoisting rope to raise and lower a light cage.

Jan 1, 1958

By Morris Loshinsky, George Ziegler

NEW ROUTES - 63rd STREET CROSSTOWN The New Route construction along East 63rd Street in Manhattan began in 1969 with the East River tunnel connecting Manhattan and Queens. The 63rd Street Line, once in Queens, is planned to connect to another new route called the Queens By Pass or Super Express (See Exhibit 1) which would connect to the Queens Boulevard Line at Forest Hills. The purpose of the Queens By Pass was to alleviate subway congestion to and from the Borough of Queens, whose population had rapidly expanded during and after World War II. The existing Queens Boulevard subway lines (the "E" and the "F" trains) are almost filled to capacity at their terminal stations with passengers from Long Island. Passengers boarding trains enroute from the local Queens stations have difficulty boarding crowded trains, and, at times, cannot board the trains. The New Routes, thus, were to give additional train capacity into Manhattan and thereby relieve the crowded conditions along the Queens Boulevard corridor. PROFILE - METHOD OF CONSTRUCTION The portion of the New Route passing east-west under East 63rd Street on Manhattan (See Exhibit 2) had to snake beneath intersecting structures running north and south, such as the Con Rail tracks below Park Avenue and the 80 ft deep Lexington Avenue Express track structure along Lexington Avenue. Further, the Lexington Avenue Local tracks are in a separate structure which has a high profile close to the street surface. Therefore the 63rd

Jan 1, 1981

By Antoni Czubak

It is difficult to simulate properly the vibratory transport. One does not know how to describe the influence of a bulk material layer on the transporting trough. There are few approaches, but none is satisfactory enough. Author proposes to apply a model of a dynamic dumper which simulates periodical collisions between material and the trough, when they are coming to the contact after the free flight of material above the trough. Computer calculates average speed of transported material and handling output as well. When the quantity of material on the trough is known, then the force of the dynamic dumper could be calculated. This force together with the exciting force of the vibrator are introduced into equations describing the model of a mutti- mass conveyor. The basic goal of simulation is to find the required exciting force and the power of an electromagnetic vibrator. it is possible to find optimal data of designed elements of vibratory conveyors as well.

Jan 1, 1996

By Y. M. Jiang

From underground instrumentation data and from direct observation of longwall panels, it was demonstrated that growth of the main-roof overhang causes an extremely high roof weighting on the face supports. This can result in catastrophic effects on the supports when the roof-weighting intensity far exceeds the support capacity. In this paper, a comprehensive study was conducted on the characteristics of main-roof breakage and its effects on shields at different locations along the face. The study was based on monitored shield data, theoretical analysis and finite element analysis. With the help of theoretical analysis and numerical modeling, stress distribution and redistribution in the main roof were analyzed to define the main-roof failure modes and to understand the maximum roof-weighting intensity imposed on the shields. From this study, it was found that the effects of main-roof breakage on shields are chiefly related to the shield's initial-setting condition and to the final failure mode of the main roof.

Jan 1, 1996

By Meliton M. Garcia, Satya Harpalani

The volume of gases produced in major and trace amounts as a result of detonation of explosives in an underground mine was determined. The volumes of major gases (CO, CO2, NO and N02) were measured immediately following detonation, during the mucking operation, and following the removal of muck. Tests to identify and quantify the gases produced in trace amounts were performed following the detonation only. The composition of the gases produced varied significantly depending on the composition of the explosive/blasting agent. An average of 95% of the gases produced were found in the test chamber immediately following the detonation, while 2% was found in the chamber following the removal of the muck. Several compounds were identified in trace amounts. Of particular interest was the detection of benzene, toluene, butenes, ethyl benzene and naphthalene since exposure to some of these compounds, even in trace amounts, could present a serious health hazard.

Jan 1, 1987

By Eric C. Schwamberge, Clem A. Pelletier, Deborah L. Muggli, George W. Poling

The Pit Lake at Island Copper has evolved into a 3-layered meromictic system. Acid Rock Drainage (ARD) is collected and injected into the lake at 220 m depth via 2 diffuser systems. In situ dye studies were conducted during 2 differing hydrological regimes in order to determine the behavior of the ARD plume within the Pit Lake. Results indicated that when runoff from the waste dumps was low, the injected ARD remained within the bottom half of the intermediate layer of the Pit Lake, initially below depths of 90 m. However, when runoff from the waste dumps was high, the injected ARD at -220 m depth rose through the intermediate water column layer rapidly, but did not breach the top pycnocline at -10 m depth. Overall, the system is currently performing as a mixing bowl with a strong boundary or cap at the upper pycnocline. maintaining mixing below the 10 m depth water level.

Jan 1, 2000

By R. L. McNearny, K. A. Barker

A study was conducted to compare physical and numerical models of the block-caving mining method. Results from the numerical analysis closely simulated the blocky behavior of the physical model, including bridging and interlocking of the simulated orebody during draw. The draw-down patterns and the rate of draw developed during numerical modeling also closely simulated the physical models. An unexpected result from the numerical modeling was the development of a zone of downward deflection which preceded the development of the zone of material movement.

Jan 1, 1999

By K. G. Correia

The replacement of the dry mining method at Guajú Mine by the dredging method was a means of ensuring its feasibility by maintaining the production levels. Dry mining increased the cost of the deposit with the distance and presented a limited mined volume, while the decreasing grade of the deposit led to a production drop. With the new methodology, there was a considerable reduction in unit cost of the mine and an increase in the production level of a deposit with low heavy minerals content.

Jan 1, 2005

By Kalle Hakalehto

Automation and mechanization in mining has no value of its own. It has to be measured in economic terms or in Increased safety or in the utilization of deposits which otherwise were unavailable. The mechanization and automation of workphases in the mining and rock construction process has led to the decrease of manual work. This has had a very essential importance in the countries where the labor is expensive or where there has been difficulties in the availability of labor. The work has become much more efficient. We would like to argue that the need of mechanization has been initiated mostly from the above mentioned reasons. The origin has seldom been the "process" approach or the real need or will to change the way mining is done. Through mechanization bigger unit sizes of machines and operations have become possible and better efficiency is achieved. This has led to new problems as well, but in most cases they have been solved so that better and more economic outcome than before has been the end result. The changes have thus been justified. It is perhaps feasible to state already at this stage that we see that the mechanization andautomation steps in the difficult conditions of mining have been remarkable. There is not a slightest underestimation of the achievements and importance of this development in our mind. Where we are to- day is the result of the experience, know-how and technological excellency of all the parties involved. The natural approach to automation has been through mechanization and automation of individual unit operations and machines. This has been the way as well in manufacturing industry as in mining. There may not have been any other way. The other presentations in this session tell us very clearly of the approach .which the machine manufacturers have taken. They have not done it alone but 'most of the initiatives have come from them. A good use of their present achievements gives many possibilities to increase the, efficiency in mining. We would, however, like to extend the view one step further to the future:

Jan 1, 1989