Method for determination of the state of hazard of rock bursts on the basis of knowledge of natural and mining conditions (in Polish)

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824110 EFFECT OF A SURFACE ACTIVE AGENT ON THE OUTBURST BEHfVIOUR OF COAL (IN RUssIAN) Sorokoletov, V }I Ugol Ukr, ~ , Jan 1981, P33-34 L~boratory investigstlons were carried out to investigate the efficiency of water containing a surf~gce active agent, polyacrylamlde~ in reducing outburst hazard in coal. Injection of the polyacryl3~mide in water into outburst-prone coal reduced the coal's elastic properties. Creep of the coal sample increased~ indicating a reduction in outburst hazard. Underground tests showed that use of the polyacryla~[de, instead of Just water, increased the coai moisture content by 30 per cent, and reduced the co~ul strength by I0 per cent. 824111 DYN/$ffC JOKP HOD~ALING OF A ROCK PILLAR BURST (IN POLIS~ ) Dreseher, %] Lietz, J /.rch Corn, V26, N2, 1961, P383-403 A one-dimensional model of a pillar-roof system in which softening of the pillar rock and elastic unlo~;~ing of the roof rock can lead to internal inst,~bility is used in the analysis of outburst in a rock pillar. Numerical values for the mnximum kinetic energy of the burst and its time-lupse are given for a wide range of meehan~c:~l constants of rocks. 824]]2 EFFFCT OF POEOSITY ON THE PHENO~NON OF ROCK ~A~9 GAS HASS OUTBURSTS (IN POLISH) Litwiniszyn, J ~mch Gorn, %~76, KL, 1981, P3-15 Rock and g:~s outbursts, viewed as a process of detor~±tion c
824117 MEmfHOD FOR DETERMINATION OF THE STATE OF HAZARD OF ROCK BURSTS ON THE BASIS OF KNOWLEDGE OF NATURAL AND MINING CONDITIONS (IN POLISH) Bilinski, A Przegl Corn, V37, N7-8, July-Aug 198], P415-423 Rock bursts occur when se~is under thick, strong rock beds are worked. The risk of rock burst is proportional to the maximum ~mmount of rock breakage which can occur during working of a face, and a method of determining this risk is presented. The method can be used to select the safest mining conditions. 824118 PROBLEM OF STRUCk~JRAL CONTINUITY IN SEAMS LIABT~ TO GAS AND ROCK OUTBURSTS (IN POLISH) Fenc, W Przegl Gorn, V37, N6, June 1981, P291-299 The influence of mining on variations in the seam structure are discussed. The probability of propagation of these variations and their influenee on outburst risk are determined° 824119 TOWARDS THE PREDICTION OF FRE-KINING ~ R E s S E S IN THE EL~0PEAN CONTINENT Blaekwood, R L Proc Conference on the Application of Rock Mechanics to Ctf6 and Fill Mir/ng, Lulea, 1-3 June 1980 , P36-39. Publ London: I~,~,

1981 Discusses how in-situ pre-mining stress measurements can be used to predict the maximum stress magnitudes that are likely to occur in a given ~[ning context, le the worst stress case, for preliminary design or feasibility study purposes. 824120 STRESS KEASUPJggENTS IN NASLIDEN FINE Leijon, B; Carlsson~ H; Myrvang, A Proc Conference on the Application of Rock Mechanics to Cut and Fill Mining, Lulea, 1-3 June 1980, P162-168. Pmbl London: I ~ ,

198~ The Leeman 3-dimensiorml overcorlng technique was used at 5 locations on levels that r~nged from 210 to 460m below surface. The rmljor and intermediate principal stresses are sub-horizontal and directed, respectively~ perpendicul~ ~nd ptu~ul!e% tL the schistoslty of the wallrock
1981 Stress strain relations have been established in the lab by means of l-dimensior~ oedo~eter tests on fills of varying void ratios. Stresses may thus be calculated with a contribution from silo theory for the self-weight of the fill. Good agreement is obtained with measurements from Nasliden mine. In the mine the weight of the fill contributes 70-80 percent of the tot~l stress and convergence between the hanging wall and