Investigation into near-contour stresses in stoping with backfilling by the polarization-optical method

Abstract

When mining deposits with room-and-pillar methods with backfilling, available hanging wall rocks and ores of medium or low stability can cause hanging wall rock collapses into stoping areas, thus causing escalation of ore dilution with waste rocks. The research work is aimed at determining areas of maximum stresses and their quantitative characteristics which can cause collapses of hanging wall rocks in the mined-out stope area and developing technological solutions to reduce concentration of stresses. Options of mining stopes located on the hanging wall of the deposit are investigated on polarization-optical models. According to the results of studying polarization-optical models with different designs of stope chains, there are obtained stress fields for each model in the zone of stope influence. The research reveals that when using a stoping method with partial processing of hanging wall rocks in the contact plane with the country rocks, the maximum stresses are much higher than in case of the arched form of the stoping area. On the basis of the obtained research results, it is recommended to carry out chambers with the formation of a vaulted shape of the roof from the hanging side in order to reduce the clogging of the ore.