Metodyka badań mezoskopowych zjawisk tektonicznych w wyrobiskach górniczych

Wojciech Salski

Abstract


A METHOD OF MESOSCOPIC INVESTIGATIONS OF TECTONIC PHENOMENA IN MINE WORKINGS

Summary

Tectonic investig1ations are very important during the exploitation of mineral deposits, mainly on account of the possibility of determining both the geometrical properties of the deposit more in detail and the engineering-geological and hydrogeological conditions. In addition to this, the necessity of carrying out such investigations results from the insufficient reconnaissance of tectonics during the working out of the geological report. On account of particular features of the environment represented by a mine, the character of geological research is different from that in the opencast mines. Linear orientation of mine workings, extraction of rock material using explosives, and invisibility of numerous small structural forms strongly affect the credibility of the results obtained.

The works carried out on measurement and observation methods of rock fractures and jointing in copper ore mines within the Fore-Sudetic monocline allowed the author to draw the following conclusions:

1. Spatial orientation of mine workings considerably affects the fracture system observed during measurements. Mine works make that fracture planes running at an acute angle to the wails of mine workings become more visible, though fractures oriented perpendicularly remain invisible. Thus, the above picture does not reflect natural proportions between the directions of fractures in the rock massif. The actual directions of fractures can be presented only with the aid of the measurements made in the mutually perpendicular galleries, and along the same distance.

2. At the opposite walls of the same gallery different directions of fractures can be observed. Thus, the measurements should comprise both planes. In the case of fine fractures on small planes these can be the opposite walls of the same gallery. The presence of strong fractures cutting the entire mine workings makes the retention of this principle impassible, since such fractures would be recorded twice. In this situation measurements should be made at the opposite walls in two parallel galleries.

3. The appropriate interpretation of the results of investigations considerably depends upon the choice of the methods of graphical synthesis of the measurement materials, and upon the competence for making the comparison of these materials. His advisable to present the results of measurements both in the shape of the rose of fractures and in the form of contour diagrams, mainly due to their complementary character.

4. The preciseness in the reconnaissance of the phenomena of jointing and fractures notably depends on the representativeness of the range of measurements.

This value ranges considerably and depends upon the quantity of fracture directions in a given area, and upon the degree of their scatter. The representative range of fracture measurements for the individual Permian and Triassic series within the south-eastern part of the Fore-Sudetic monocline is predominantly contained in an interval of 500­750 measurements.

 


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