Most of the lead-zinc mines in the state of Rajasthan, India currently employ the blast-hole stoping method with backfilling. One of these mines, Rajpura Dariba mine, has reached a depth of about 700 m. In this mine the footwall and hangingwall of the orebody contain sheared regions, represented by narrow 0.1–1.2 m zones of crushing, brecciation, and gouging, which are fairly persistent along the strike and dip, and are found close to the orebody contacts. Extraction of ore from these lodes is challenging at greater depth. Major geotechnical issues encountered during stoping include maintaining footwall drives and crosscuts, especially when they are closer to the stoping areas and crossing a shear zone, premature collapse of hangingwall rock prior to mucking of ore, and instability on account of blast vibration. In this paper we discuss the findings from three-dimensional numerical modelling studies conducted using FLAC3D to arrive at a feasible stoping sequence for maximum ore recovery. The sequence finally suggested involves an upward mining sequence using primary and secondary stoping configurations with sill pillars and vertical (rib) pillars. The influence of stoping, as seen in numerical models, extends about 25 m into the footwall; this is corroborated by field observations, where the footwall drive within 25 m of the stope experienced severe spalling and roadway closure. The influence of shear zones was found to be crucial in locating the drivages and designing the stoping sequence at greater depths.


Lead-zinc mining in the state of Rajasthan, India has been conducted since ancient times. Rajpura-Dariba mine is located at the southern extremity of the Rajpura-Dariba Bethunmi metallogenic belt in Rajsamand district, Rajasthan. The orebodies at Rajpura Dariba are designated as the Main Lode (South and North) and East Lode as shown in Figure 1. The Main Lode extends over a strike length of 1700 m and is separated into South Lode and North Lode by a barren stretch of 300 m. The South Lode (L1), striking north-south and dips 60° to 70° towards the east, and has a strike length of 500 m. The North Lode has a strike length of 900 m. It strikes N-S and dips 70° to 75° towards the east. The average widths of South, North, and East lodes are about 24 m, 18 m, and 18 m respectively and tend to decrease with increasing depth.

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