DBPapers
DOI: 10.5593/sgem2017/13/S03.051

IMPACT OF THE PACE AND ADVANCE OF EXPLOITATION ON THE SEISMIC HAZARD- CASE STUDY FROM A POLISH COPPER MINE

A. Gogolewska, J. Jakubiak
Monday 11 September 2017 by Libadmin2017

References: 17th International Multidisciplinary Scientific GeoConference SGEM 2017, www.sgem.org, SGEM2017 Conference Proceedings, ISBN 978-619-7105-00-1 / ISSN 1314-2704, 29 June - 5 July, 2017, Vol. 17, Issue 13, 399-406 pp, DOI: 10.5593/sgem2017/13/S03.051

ABSTRACT

The threat of seismic activity is an inherent part of the operation in each of the three mines owned by KGHM Polish Copper JSC. It results from the high compressive strength of the rock, the high depth of retreat, and the significant tectonic of the deposit as well as human mining activity. There is no complete elimination of this threat, but adequate prevention is used to limit it. Impacts on this threat also include operational indicators such as advancement or progress and pace of mining work. The progress is defined as the amount of ore extracted during a time unit given. The rate or pace of exploitation is considered as the distance between successive location of the front line in a time unit, i.e. the speed to pass this distance.
The main objective of the study was to estimate the influence of progress and the rate of mining on the seismic hazard in one mining panel in a Polish copper ore mine.
An analysis of seismic activity in this field was carried out throughout its life cycle, i.e. 5,75 years. There were no dynamic events such as bumps, but seismic activity (number and energy of shocks) was high. The impact of progress and rate of exploitation on seismic and rock-bursts was also determined. Analysis of advancement was made on the basis of output data. The work rate was calculated based on the difference in the distance between the successive positions of the front line.
The amount of extracted ore is usually given in tons, and progress reports are usually conducted monthly, semi-annually or annually. Analysis of the impact of the progress on seismic hazard was carried out in semi-annually terms over three years. It concerned the impact of mining volumes on the number and cumulative energy of seismic shocks recorded in this field. For each half-year, the rate of extraction was also calculated, describing how much Joule of energy falls on 1 Mg copper ore extracted in a time period given. It turned out that the number of shocks as well as the sum of the energy of these shocks increased during the first 3 months. This might indicate that seismic energy emitted by shocks did not always increase with rising production.
An analysis of the influence of the rate of exploitation on the seismic hazard was also carried out. This was a semi-annual analysis. It was found that in most cases, as the work rate increased, the number and total seismic energy of a given period increased. However, this rule did not always find confirmation like during the one half of one year, in which the number of shocks and their total energy was higher than in previous periods, but the pace of work was lower than before. In this half of year, the number of shocks was the highest, this period was also characterized by the greatest progress of the front line, but the total energy was lower than in the previous half of the year, which was characterized by similar pace of work and a similar number of shocks. It can be stated that the increase in the number of tremors could be related to the increase in the pace of work, while the increase in shock energy was not related to the progress of the front line. As in the case of progress, a separate analysis has also been carried out for high-energy shocks. It showed that the impact of the exploitation rate on the seismic hazard in the field in relation to high-energy shocks was the same as for all tremors.

Keywords: copper ore underground mining, exploitation advancement, seismic hazard, rock-burst prevention