Morales, RF, Henriquez, JO, Molina, RE, Araneda, OA & Rojas, EG 2007, 'Rock Preconditioning Application in Virgin Caving Condition in a Panel Caving Mine, CODELCO Chile El Teniente Division', in Y Potvin (ed.), Proceedings of the Fourth International Seminar on Deep and High Stress Mining
, Australian Centre for Geomechanics, Perth, pp. 111-120.
The deepening of the mine operations at El Teniente involves exploiting more competent rocks which are
under higher stresses. In the particular conditions of El Teniente Mine, this has meant an increase in the
seismic activity induced by the mining.
Among several techniques that El Teniente has utilised to face this problem, it recently decided to use a
preconditioning technique for the in situ rock mass, through hydraulic fracturing, in one of the exploitation
sectors of the deposit. This application was carried out in at the start of a virgin caving condition; a
situation that constitutes an exceptional case in the history of the mining industry.
At this present time, the results obtained confirm the expectations of reaching improvements in cavability,
seismicity and productivity, in the management of the caving process. In practice, the observed outstanding
effects were in the seismic activity and cavability. With regard to seismic activity, a notable decreasing of the
seismicity level was observed during the process of connection to the upper crater. With cavability, an
increment in the propagation rate of the caving (reduction in the ramp up period) was observed, which will
allow the steady state production to be reached sooner.
In this way, preconditioning, particularly the hydraulic fracturing, will transform into a very important
technical option to incorporate at the beginning of the exploitation of a new sector, with different
expectations regarding the condition of caving in state, offering exploitation scenarios with smaller risk,
greater control and greater profit value. The previous issues will facilitate the exploitation of the great
quantity of geological resources that exists within the Division.
Future applications of rock preconditioning in full production sectors will allow its validation, in order to be
introduced industrially to the exploitation by Block and Panel Caving systems in the El Teniente Mine.