TY - THES

T1 - Investigations into the possibility of applying an underground bulk method for talc mining in the north part of the Rodoretto deposit, Italy

AU - Hatzl, Franz

N1 - embargoed until null

PY - 2007

Y1 - 2007

N2 - The aim of this thesis was to find an alternative mining method to the currently used underhand cut and fill method for the Rodoretto underground talc mine. Firstly, all available information concerning depth, thickness, dip, geometry, quality distribution and reserves of the north part of the talc deposit was put together. Based on available studies, all information in terms of rock and rock mass conditions of the talc, the hanging wall and the foot wall as well as data coming from inspections of cores and rock mass classifications were compiled. The Mathews method for determining the open stope stability showed that the competent hanging wall micaschist could stay open over spans of 30x30m or even larger, depending on the dip. Given the low strength of talc, any mining method using pillars was eliminated. Therefore, caving and sublevel stoping were investigated as the most promising methods. Due to the weak orebody rock, caving without restriction to above would result in large voids, thus leading to a situation difficult to control. This problem could be avoided by using down-dip, transverse sublevel stoping with a sublevel spacing of 10m and the stopes being backfilled from above with a strong, cement paste backfill. To restrict the caving upwards, a stable roof using cut and fill could be established above the first production level. Additionally, the use of pipe roofs to improve drifting and reinforce production drifts was worked out.

AB - The aim of this thesis was to find an alternative mining method to the currently used underhand cut and fill method for the Rodoretto underground talc mine. Firstly, all available information concerning depth, thickness, dip, geometry, quality distribution and reserves of the north part of the talc deposit was put together. Based on available studies, all information in terms of rock and rock mass conditions of the talc, the hanging wall and the foot wall as well as data coming from inspections of cores and rock mass classifications were compiled. The Mathews method for determining the open stope stability showed that the competent hanging wall micaschist could stay open over spans of 30x30m or even larger, depending on the dip. Given the low strength of talc, any mining method using pillars was eliminated. Therefore, caving and sublevel stoping were investigated as the most promising methods. Due to the weak orebody rock, caving without restriction to above would result in large voids, thus leading to a situation difficult to control. This problem could be avoided by using down-dip, transverse sublevel stoping with a sublevel spacing of 10m and the stopes being backfilled from above with a strong, cement paste backfill. To restrict the caving upwards, a stable roof using cut and fill could be established above the first production level. Additionally, the use of pipe roofs to improve drifting and reinforce production drifts was worked out.

KW - Abbau unter Tage

KW - Talk

KW - Abbauverfahren

KW - Rohrschirm

KW - Bruchbau

KW - Kammerbau

KW - Stabilität nach Mathews

KW - Underground Mining

KW - Talc

KW - Mining Methods

KW - Pipe Roof

KW - Caving

KW - Sublevel Stoping

KW - Mathews method

M3 - Diploma Thesis

ER -