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The operation of a photoelastic sensor outside the zone of influence of extraction operations can be represented as follows. After the drilling of an isolated borehole of small diameter and the installation of the sensor in it, the latter operates in combination with the rock, i.e., reacts to changes in its state of stress and deformation caused by the drilling of the borehole. If the rock has creep properties, the action of the sensor will be the same as the action of an elastic ring support in a circular working with total cohesion with the solid rock, as described in [1]. In this case, the stresses in the sensor due to the creep properties of the rock will take [1] the following form:%0=--'if-3 R' ---~--a-1 r 2 --3 2r' J (1--k) sln20.(1)The coefficients in (1) depend on the elastic constants ax, bt, a-l, b_l, as, b-s of the sensor material and rock, the ratio between the internal and external diameters of the sensor, the creep parameters of the rock, and the time.It is known that the stress components o r, o 0 , rr0 at any point in an elastic sensor are related as follows to the maximum tangential stresses Vma x by the elasticity relation:~lll aX --

Among the various forms of dynamic manifestations of rock pressure, rock bursts have been moved to the focus of attention of investigators as a specific form of uncontrolled conversion of accumulated potential energy into kinetic energy and brittle destruction, particularly in conjunction with the increasing depth of mining operations and their high concentration.The store of experience [i, 2] in this area and new results at the juncture between mining and geophysics provide a base for formulating new problems important for practical mining.Among the new results, one should cite the data of Sadovskii [3, 4] on the relationship between earthquake energy and source size and the data of Knoll on similar energy relationships for rock bursts.The dynamics of the evolution of a rock burst and a smallsource crustal earthquake are regarded as similar phenomena [4].Classification of rock bursts has always been an important aspect of their study. Petukhov noted the following facts used by various investigators to classify rock bursts [i]: distance of the burst source from the exposure [2], the site of manifestation of a rock burst [5], the mechanical properties of coal seams [6], and the magnitude of seismic energy [I]. In discussing these factors, Petukhov noted that "none of the classifications proposed covers the entire variety of conditions and manifestations of rock bursts."In the framework of the theory of rock bursts as it existed in 1972, Petukhov believed that two types of classification of rock bursts would be convenient [i]: a) by intensity of manifestation of a rock burst and the resulting destruction, and b) by distribution of rock bursts according to their locations.In [7,8] two forms of classification of rock bursts were further elaborated.According to intensity, rock bursts are subdivided into the following groups [i, 7, 8]: bumps, shocks, microbursts, and true bursts.In [9] two groups were added to this classification:spalling and intense loosening.The characteristic physical feature of classification by location (specifics of loading) is the fact that it refers to the conditions of energy influx from the external system -surrounding rocks --in an implicit form.The authors of [8] noted that this "classificaton according to location does not include rock and tectonic bursts caused by sudden movements (destructions) inside the rock bed." These classifications were extremely important for the development of safe methods of mining in case of rock bursts in marginal zones. As the mining operations advanced to greater depths, however, the proportion of intense rock bursts increased [i0, ii].Consider the group of "true rock bursts." According to [9], "true rock bursts" are the category comprising all intense dynamic events.The true rock bursts, according to [9], Institute of Mining, Siberian Branch, Academy of Sciences of the USSR, Novosibirsk.