938 KIRSC"HKE, D Contribution to rock seepage studies. Congress. Discussion. In German. IF. PROCEED. 2 CONGRESS.INrERNAT. SOC.ROCK MECH.BELGRAD, 1970,V4,1974,P497-498. The writer suggests the following methods of measuring the seepage of rocks: i. Systematic comparison o~ results o~ idealised rock bodies with those obtained in studies of rock masses; 2. Cc~parison of mathematical correlation between seepage in rock samples and water flow measured by using water ~au~es; 3. Investiggtlon of accuracy of Joint measurements.
Underground excavations 939 OB~T, L Reporting of underground failures; Congress. Discussion. PROCEED. 2 CONGRESS, INTE~AT. SOC .ROCK MECH. BELGRAD, 1970,V~, 1974, P~06. TO encourage the reporting of undecground failures it is suggested that at the next Congress at least a part of one session be devoted to the reporting of failures and the corrective procedures that were effected. Also it is suggested that the Society might consider establishing a Com~dssion to document similar oc curances. 94O HABENICHT, H INST. FUER B~GBAUKUNDE, LEOBEN, A Roof structure in underground openlngs.Congress.Discussion.ln German, PROCEED 2 CONGRESS, INTERNAT.SOC.ROCK MECH.BELGRAD, V4,1970, P403-405 •
Mines See also abstract 1083. 941 HARGRAVES, AJ The longwall face in coal mining. Congress. Discussion. PROCEED. 2 CONGRESS, I ~ N A T . S O C . R O C K MECH, BELGRAD, 1970, V4,1974, P406-407. The time factor is important when considering the longwall face. In the coal ahead of the face are three gradients, at least two of which are markedly related to rate of advance, the temperature gradient and the gas pressure gradient. Both gradients are steepened by increase in rate of face advance. Because of such considerations, the tilt and breaks of roof take place ahead of the face and the slower the face advances, +he further ahead of the face do these cracks occur. Measurements in Australia of thermal and serption coefficients of expansion of coals and roof tilt on faces indicate the significance of these factors. 942 KOSTAL, Z Projected system for mining horizontal seams in the saddle strata of the Ostrava-Karvina basin by lomgwall methods. In Czech. UHLI, V21, Nll, 1973, P453-458. This article deals with +.he principles of extracting such seams by longwall workln~, and quotes operational experience and research results. A schematic model for mining thick seams, taking into account roof and floor conditions, is presented.
943 LATADIE, H Rapid depreciation of modern equipment in drifting operations. In French. INDUST. MINERALE, SERIE MINE, N4,1973, P242- 247.
PABKER, J How to design better mine openings. Part 5 of Practical rock mechanics for the miner. 25F. ENGNG.MIN. J.V174, N12,1973, P76-80. 945 MAMEN, C Canadian mine technology - 1973. Fi~s,2T. CAN. MIN. J.V95, N1,1974, P20-39. A general report is presented considering the productivity of Canadian mines, and a review of char~es and developments, during 1973, in m i n i ~ methods etc. is given by considerln~ reports from fourteen minin~ companies concerning operations at their mines in Canada.
ANONYMOUS Copper mining at Cobar.-An account of the mining, stoping, stope filling, hoisting, grinding and ore handling operations at this mine. 5F. AUSTRAL. MIN. V65, N12,1973, P16- 22. 947 SKEPHERD, R The forward abtd~ent in lor~all mlnin~.lOF,16R. COLLIERY GUARD.MAY, 1973, 6P. This article aims to show how roof breaks can original through abutment action but cannot be sufficient to induce satlsfactc~y caving unless the mode of application of pressure through support legs is effective. It is shown that better caving could be obtained when conventional supports are used if the fc~ward legs have a higher rating and hence give higher support density than the intermediate or rear legs. 948 HEEWIG,H The effects of face edges on the condition of the roo~ in the coal face.In German. GLUCKAUF, V109, N23,1973, Pl139-1142 • Face ribs affect the roof of seams beir~ worked under. neath them and can give rise t.o an increase of at lea: 30% in rock pressure° A rib running in the direction the working face at a separation of 60m can increase the pressure by 30%. 949 JACOBI, 0 The relationship between rock pressure and conver=encq in =ateroads.In German. GLUCKAUF,V109, N23,1973, Pll42-1147. As a result of mod~l tests, calculations of strata pressure and measurements of convergence, characteris~ curves for roadways have been constructed, plotting conv~gence against pressure. The shape of these cur is discussed and their applicability to different shal of raadway under different working conditions is illustrated. 95o BI SHOP, EE Newstead colliery. Progress through experience. 5F, 3T, 2R. MIN. ENGR.Vl33, MARCH, 1974, P225- 236 • The author describes the various face designs used and experiences Rained whilst being a Colliery General Manager. Outlines are given of +he various develolmnents which have taken place s i ~ e the ROLF (Remotely Operated Longwall Face) system was introduc in 1962. .~.dzalis are given of v a t , u s problems which arose and how the co~lete mechanizabion of stsble holes hss come shout over these years.