Design and performance of shotcrete-bolting support for a tunnel in a special weak rock

Design and performance of shotcrete-bolting support for a tunnel in a special weak rock

151A 874175 Detonation driven air shocks in the air gap between a charge and its confinement Bjarnhoh. G: Smedberg. U Swedish Detonic Research Founda...

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151A 874175 Detonation driven air shocks in the air gap between a charge and its confinement Bjarnhoh. G: Smedberg. U

Swedish Detonic Research Foundation report DS 1986.5, 26 Not" 1986, IOP The detonation front and the precursor air shock (PAS) of air decoupled explosives were studied by high speed photography of charges in a plexiglass tube of square cross section, half filled with explosives. The expansion of the explosive products (EP) into the air gap, and the reflection of the PAS against the confining roof, and the following expansion along the air gap were followed for several different explosives. Computer modelling was also carried out. The effects of PAS induced compression of the explosive on detonation are discussed, and practical methods to optimise the speed of the PAS are suggested.

874179 Water-jetting techniques: existing and potential uses for underground services Fairhurst, R M: Saunders. D H In: NO-DIG 85. Trenchless Construction for Utilities (Papers

to the Conference, London, 16-18 AprU 1985) P235-249. Pub/ London: Institution o/" Public Heahh Engineers. 1985 Water jets are used for a wide range of cutting and cleaning activities. Existing applications to plain water jet drilling and water jet assisted mechanical drilling, pure water jet tunnelling in soft ground, and water jet assisted disc cutters and roadheaders are described. The recent development of abrasive-containing water jets for rock cutting is also presented. Applications to trenchless construction are considered. Much of the machinery described is still in the development stages, and hoped-for advances in this technology are discussed.

Avail." The Foundation, Box 32058, S-126 11 Stockholm, Sweden

Rock and Soil Reinforcement and Support

Crushing and grinding 874176 Predetermining average fragment size: a case study Gozon, J S: Britton, R R: Fodo, J D

Proc Symposium on Application of Rock Characterization Techniques in l~line Design, New Orleans, March 1986 P190195. Publ Littleton." AIME. 1986 An ongoing concern of surface mine operators is the control of rock fragmentation. The average size distribution of broken material is important to economical and efficient hauling and crushing. A method utilizing the Kuz-Ram technique modified using a Weibull distribution function has been proposed and some of the results obtained during the laboratory and field tests of this research are examined.

874180 Design and performance of shotcrete-bolting support for a tunnel in a special weak rock Tao Zhen-yu

Tunnlg Undgr Space Tech VI, NI, 1986, P49-51 A special condition of weak rock, where a hard rock contains developed and concealed microcracks in a highly geostressed region, is examined. The basic properties of such a rock mass in a highly' geostressed region and the tunnelling method used with this type of rock are discussed.

Bolts and anchors See aL~o. 874154

Machine excavation 874177 Bucket wheel excavator performance at Neyveli lignite mine Kumaraswamy, S; Mozumdar, B K

AIin Scl Technol V4, N3, .~[arch 1987, P213-223 Bucket wheel excavators have been in use at the Neyveli Lignite mine, India, since the early' 1960s. The performances of the BWEs at Neyveli have been statistically analysed to determine the effects of physico-mechanical properties of overburden, blasting and rainfaIl on machine productivity, availability, wear-and-tear of bucket teeth, power consumption, production efficiency' and cost of mining. 874178 Introduction of the Robbins mobile miner to Mount lsa Mines Limited Grills, R G: O'Neill, T J; Howarth, D F Proc 13th Congress of the Council of Mining and

Metallurgical Institutions, Singapore, 11-16 May 1986 I/3, P211-219. Publ Parkrille. CMML/AIMM, 1986

874181 Re-assessment of strata bolting Newson, S R

Min Engr V146, N306, March 1987, P585-597 The use of roof bolts as a means of primary support between the tips of powered supports and the face on face salvage operations, and as a supplementary support in roadways is increasing, with satisfactory' results. Some of the major criteria regarding bolted support design are outlined. The current state of knowledge on bolt design, design theories, bolting machinery and monitoring techniques is briefly reviewed and evaluated. The need for controlled monitoring trials is stressed, and it is concluded that this could lead to the introduction of safe and efficient systems of roof bolting as a primary means of support in underground roadways. 874182 Mechanism of full-column resin grouted bolts (In Chinese) Li Xiren; Zhu Fusheng: Jin Yindong

Nonferrous Metals V38, Not, 1986, P19-28

Rock bolts are widelv used in under~round and surface rock The Robbins Mobile Miner MM 120-3001 is a continuous _ engineering. A study~ of the mechanism of the full-column hard rock mining machine which uses a swinging vertical resin grouted bolt is presented. The distribution of the axial wheel-type cutter head, and is mounted on a crawler. It proforce along the bolt, the shear force acting on the rock mass, duces near rectangular drifts with much less wall damage, and and the additional stress and displacement fields resulting thus lower support requirements, than those excavated by from that shear force are examined. A method for designing blasting. Field tests in a quarry and its use to drive a decline at rock bolting systems is discussed. This work considers support the Mount Isa Mine, Australia, are described. of a circular underground opening. 1987 Pergamon Journals Ltd. Reproduction not permitted