JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech IV PLANNING OF SURFACE MINING TECHNOLOGY PROJECT Previous Question Paper (March - 2021 - R16)

A Master Plan in the context of surface mining is a comprehensive, long-term strategic document that outlines the entire lifecycle of a mining project. It integrates geological, technical, economic, environmental, and social factors to provide a roadmap for the systematic extraction of mineral resources from exploration through to final mine closure and land reclamation.

The steps involved in developing a Master Plan include:

1. Resource Estimation and Geological Modeling: This involves detailed exploration to define the ore body geometry, grade distribution, and rock mass characteristics. Data is processed into a 3D block model to determine the quantity and quality of the reserves.
2. Mine Design and Planning: This step defines the pit limits, bench geometry, haul road layouts, and waste dump locations. It involves selecting the mining method and determining the optimal production sequence to maximize resource recovery while ensuring safety and stability.
3. Equipment Selection and Production Scheduling: Based on the mine design, the required fleet of excavators, drills, and haulage trucks is calculated. A production schedule is developed to balance stripping ratios and ore output over the life of the mine.
4. Infrastructure and Logistics Planning: This covers the design of essential support facilities, including crushing units, beneficiation plants, power supply, water management systems, workshops, and transportation networks for product dispatch.
5. Economic and Financial Analysis: A detailed evaluation is conducted to estimate capital expenditure (CAPEX) and operating expenditure (OPEX). Financial indicators such as Net Present Value (NPV) and Internal Rate of Return (IRR) are calculated to assess project viability.
6. Environmental and Social Impact Assessment (ESIA): This step addresses regulatory compliance, including mitigation strategies for noise, dust, vibration, and water contamination, alongside community engagement and land rehabilitation plans.
7. Mine Closure and Reclamation Plan: A strategy is formulated for the post-mining phase, detailing how the land will be restored, contoured, and revegetated to ensure long-term environmental stability and safety after operations cease.

To achieve a production target of 10 million tonnes (MT) per annum in a surface mine with the specified geological conditions, a large-scale mechanized open-cast mining system is required. Given the seam thicknesses (10m, 6m, 8m) and partings (5m, 4m), the total coal thickness is 24m and total overburden (OB) is 9m, with a shallow depth of 60m. This configuration is suitable for a shovel-dumper or surface miner combination.

The equipment selection is based on the stripping ratio and the need for selective mining to handle partings:

1. Excavation and Loading: For a 10 MT annual output, high-capacity electric rope shovels (15-20 m³ bucket capacity) are required for overburden removal. For coal extraction, surface miners (e.g., Wirtgen 2500 SM) are recommended to maintain high quality, minimize dilution, and eliminate the need for drilling and blasting in coal seams.
2. Haulage: A fleet of 100-tonne to 150-tonne rear-dump trucks is necessary to match the shovel/surface miner cycle times. The number of trucks should be calculated based on a cycle time analysis considering the 60m depth and haul road gradients.
3. Drilling and Blasting: Large-diameter rotary blast hole drills (250mm diameter) are required for overburden preparation. ANFO or site-mixed emulsion explosives are recommended for efficient fragmentation.
4. Auxiliary Equipment: Motor graders for haul road maintenance, water sprinklers for dust suppression, and dozers (track-mounted) for bench preparation and clean-up are essential to maintain productivity.
5. Crushing and Handling: A semi-mobile in-pit crushing and conveying (IPCC) system or a fixed surface crusher with a capacity of 2000-2500 tonnes per hour (TPH) is required to handle the 10 MT throughput and prepare the coal for transport.

The specific fleet size should be determined by calculating the total volume of OB and coal to be moved annually, applying a 15-20% availability factor, and ensuring the system capacity exceeds the peak production requirement.