MINES PERFORMANCE OVERVIEW
Setting New Benchmarks through Geotechnical Engineering 
The onward journey at Hindustan Zinc is propelled by our focus on excellence across our mining operations. It is steered by our sustained focus on responsible, sustainable and innovative growth initiatives. During FY 2023-24, we enhanced this focus manifold, to touch new goalposts and create greater value for our stakeholders.
We operate eight underground mines at five locations in Rajasthan, India. These are Rampura Agucha Mine (RAM), Sindesar Khurd Mine (SKM), Rajpura Dariba Mine (RDM), four mines at Zawar, namely Mochia, Balaria, Baroi & Zawaramala, and Kayad Mine (KM). The mines are hosted by the Proterozoic-age sediment-dominated sequences formed 1,800 to 2,500 million years ago and since their origin, the ore has undergone several deformation and metamorphic events. The orebody host rocks at these mines range from very strong dolomites to foliated metasediments. The depth of mining of the orebodies currently ranges from close to surface to 1,000 metres below the surface.
ADVANCED METHODOLOGIES DRIVING FORWARD MOMENTUM
We have deployed advanced methods, using state-of-the-art tools and processes, to drive operational growth at our mines. We apply the Long Hole Open Stoping mining method at all the mines. Most of the mines employ tailings to backfill the stope voids as paste or hydraulic fills. Cement is added to ensure stability of the fill mass. This fills the void and provides support to the walls post ore extraction.
Stoping is usually mined as a bottom-up extraction sequence, with the lower levels mined first and the backfill forming the working platform for the next level of extraction. However, the reverse process, comprising top-down extraction sequence, is followed at RAM, which has emerged as a world leader in applying this novel approach.
Mining isn’t just about extracting ore, it’s about adding value responsibly and maintaining quality. This year, we’ve seen high-quality mining operations across all sites, especially at Rampura Agucha Mine and Zawar.
Praveen Sharma
COE Mining
Setting New Benchmarks through Geotechnical Engineering
As a frontrunner in the industry, constantly establishing new operational standards in mining, we have stationed Geotechnical Engineering teams at every site. These teams are responsible for defining the various mining parameters, such as infrastructure location, excavation size and stoping sequence. They also monitor the response of the rock mass to mining and form an integral part of the mining teams.
ROLE OF GEOTECHNICAL ENGINEERING TEAMS
- They collect the necessary information needed to define the mining conditions. This includes:
- Collecting rock property data from diamond drill core
- Mapping underground excavations
- Measurements of in-situ stress
- Testing the strength of the intact rock and cemented fills
- Ground water assessments
- Based on the collated information, geotechnical models of the mine are built using mining software. This enables the engineers to classify the rock mass quality and predict the ground conditions ahead of development and stoping
- The teams then undertake analysis and design, using industry leading practices. Both empirical and numerical tools are utilised in this process. The empirical methods allow the engineers to benchmark their conditions against those that occur at other mines and predict the behaviour and stability against this information. Numerical modelling allows them to input complex mining geometries, geology, rock mass properties, the in-situ stress field, and the extraction sequence. These models allow the engineers to forecast the likely stress and strain conditions prior to mining
- The engineers monitor the response to mining, using a variety of sophisticated tools including:
- Extensometers, which are grouted into the rock to measure the deformation within the rock mass
- LiDAR (light detection and ranging) surveys, which measure the deformation of the rock mass at the surface of the excavation
- Stress Cells, which monitor the stress loads imposed on the rock mass by mining
- Geophones, which have been installed at RAM and SKM to measure the micro-seismic activity that occurs when mining is undertaken at depth
Ensuring Workplace Safety
- The geotechnical teams are also responsible for the design of ground support, which ensures the stability of the excavations where the mining personnel are working
- Ground support involves
- a) bolts and cables, which are fixed into boreholes to increase the cohesion and frictional properties of the rock, and
- b) fixing mesh and spraying concrete (shotcrete) onto the walls and roof of the excavation to retain the smaller pieces of rock, preventing them from loosening and detaching
To ensure that mining geotechnical engineering expertise is available, Hindustan Zinc has partnered with the National Institute of Technology, Rourkela, to train engineers and geologists in mining geotechnical engineering, investing in its professional workforce and ensuring that these specialist skills are available for future mining.
The Company’s geotechnical expertise allows it to continue to mine successfully in variable and challenging conditions, while ensuring that the mines are safe and economically viable.
