318A rock movement, and impermeability against liquids. For prevention of corrosion, theory and laboratory tests have shown asphalt and bitumen should be selected. Studies of longevity. damage and safety of the whole system are discussed.
Underground construction methods 905512 Machine mining of narrow, hardrock orebodies Scoble. M; Dimitrakopoulos, R; Peck, J; Brackebusch. F CIM Bulletin V83, N395, March 1990, P105-112 Mechanisation of extraction from narrow, hardrock orebodies is of great interest to enhance stope productivity and safety. Typical Canadian conditions of vein environment are first illustrated, considering morphology and structure, grade variability, orebody properties, ore and wallrock quality, and in situ and induced stresses. In-stope mining machine development is considered, including disk, pick and drag bit cutting, percussion boring, and percussion ripping/impact breaking. R and D from British Coal and from South Africa, and the US Narrow Opening Mining Machine (NOMM) are described. 905513 Sandvik conquers Italian Alps Ground Engng V23. /72, March 1990, P14-14 Because of the presence of very large boulders which make drilling difficult and frequent water inflow which diluted the grout, conventional jet grouting for construction of a tunnel roof could not be used. These problems were overcome using conventional overburden drilling equipment, the Tubex (Odex) system, with simultaneous drilling and casing of boreholes. The casings were injected with grout, and at a predetermined pressure "valves" in the wall burst, allowing grout to escape into the surrounding moraine. 905514 Neolithic site kept safe under Italian umbrella Pelizza. S: Barisone. G; Campo, F; Corona, G Tunn Tuunig 1/22. N3. March 1990, P33-34 The 12m wide, 10m high Ramat tunnel was driven 500m through water bearing glacial deposits containing large boulders. Cover was low and an the archaeological site above the tunnel could not be disturbed. Jet grouting from the surface was used to fill voids where possible. An umbrella arch (Corona micropiles) was constructed above the top 7.5m of the tunnel, using 12m long tubes drilled from the tunnel face. Excavation using an excavator and large hammer to break boulders proceeded in 9m stages before the next arch was constructed. Final lining was steel arches and concrete.
905515 Big shield drive heats NATM in Algiers Martin, D Tunn Tunnig V22. N4. April 1990, P20-23 Construction of twin bore, 1000m long by 150 sq m section road tunnels through poorly consolidated sequences of clay, sands, and sandstone with overburden depth 5-25m is described. Control of surface settlement and restraint of costs of lining the tunnel in poor ground were major considerations. NATM was rejected on economic grounds, ground reinforcement by jet grouting or installation of horizontal piles to form a roof on technical reasons. A very large parabolic shield drive, with roadheader excavation and precast concrete segmental lining was used successfully.
905516 Wroclaw pipejack Sciskala. T; Kuc, H: Kozlowski. J Warld Tunnlg I/3, N2, April 1990, P99-101 Two short tunnels were required to carry sewers under roadways in Wroclaw.Poland. Pipe jacking was selected for one 33m long section. Restricted access and presence of utilities at shallow depth led to problems. The water bearing mixed alluvial soils required dewatering. Careful planning of drain pipe layout was necessary to minimise settlement. Im long by 2.6m square concrete sections were jacked from access pits. Relations between thrust and ground type and advance rate are illustrated. 905517 Cooling water for Tihange Lasudry, R; Dclbaere, D World Tunnig I/3. N2, April 1990. P114-118 Modifications to the cooling system of the Tihange nuclear power plant, Belgium, required pipe jacking with total length 600m of 3.2m diameter sections. Flow rates of 33 cubic m/s at 3bar were required. Site investigations revealed 3-5m of clay and loam over 6-8m high permeability sand and gravel with cobbles and boulders, then weathered and intact schist bedrock. Pipes were jacked at depth 10m after dewatering between slurry walls. A canal crossing was achieved using a Denys shield following ground freezing.
905518 Shaft boring application in South Africa: report on the Oryx 1B ventilation shaft project Roos. F C Proc SANCOT Seminar on Mechanised Underground Excavation, November 1989 P39-51. Publ South Africa: Gold[ields Press, 1989 The application of the large hole raise boring concept as a reliable and cost effective method for shaft construction is outlined. The V-mole shaft construction system is discussed. Different types of shaft linings, lining techniques, ventilation, muck-handling, and the cost comparison between conventional shaft sinking systems and the V-mole system are also examined. A case study based on the Oryx mine in South Africa forms the basis for discussion. 905519 Development in drill and blast techniques MacConachie, H I Proc SANCOT Seminar on Mechanised Underground Excavation, November 1989 P97-112. Publ South Africa: Goldh'elds Press. 1989 The economics of using labour intensive, low capital cost methods or of using high capital cost imported or, if available, local machinery to fully mechanise underground mining operations is discussed. Three major areas where successful mechanisation using locally available equipment has been possible in South Africa are shaft sinking, station cutting, and stoping.
905520 Current development in conventional and mechanical shaft sinking in the Federal Replblic of Germany Wollers, K Proc Conference on Skafl Engineering, Harrogate, 5-7 June 1989 P375-378. Pub/London." IMM, 1989 Developments in conventional shaft sinking techniques are outlined. Continuous monitoring of thickness of the ice wall in freeze sinking is possible by computer simulation using sensor
~f~ 1990 Pergamon Press plc. Reproduction not permitted