JNTU B.Tech III SURFACE MINING TECHNOLOGY Previous Question Paper (September - 2021 - R13)

Surface mining in India is the dominant method of mineral extraction, accounting for over 90% of total mineral production by volume. The sector is characterized by large-scale open-cast operations, particularly in the coal, iron ore, and limestone industries, driven by the shallow depth of deposits and the economic viability of high-capacity machinery.

The current status of the industry is defined by several key trends:

• Coal Dominance: Coal remains the primary focus, with major subsidiaries of Coal India Limited (CIL) and Singareni Collieries Company Limited (SCCL) utilizing large-scale shovel-dumper combinations and draglines. Projects like the Gevra and Kusmunda mega-mines in the Korba coalfields represent the shift toward ultra-mega open-cast projects with high annual production capacities.
• Mechanization and Technology: There has been a significant transition from manual and semi-mechanized methods to high-capacity, fully mechanized systems. This includes the deployment of Surface Miners, which eliminate the need for drilling and blasting, thereby improving safety, reducing environmental impact, and enhancing coal quality through selective mining.
• Iron Ore and Non-Coal Mining: The iron ore sector, particularly in Odisha and Jharkhand, employs advanced beneficiation and high-efficiency extraction techniques. Large-scale mechanized mines like those operated by Tata Steel and SAIL utilize automated crushing and screening plants to optimize output.
• Environmental and Regulatory Challenges: The industry is under increasing pressure to adopt sustainable practices. Regulatory frameworks now mandate rigorous Environmental Impact Assessments (EIA), progressive mine closure plans, and the implementation of green mining technologies to mitigate dust, noise, and land degradation.
• Safety and Digitalization: Modern Indian surface mines are increasingly adopting digital technologies, including GPS-based fleet management systems, slope stability radar for monitoring highwalls, and advanced telematics to improve operational efficiency and worker safety.

Despite these advancements, the sector faces challenges regarding land acquisition, rehabilitation and resettlement of displaced populations, and the need for deeper mining as shallow reserves are exhausted. The future status of surface mining in India is pivoting toward 'Smart Mining' initiatives, focusing on automation, AI-driven predictive maintenance, and stricter adherence to sustainable development goals.

The selection between surface and underground mining is a critical decision based on technical, economic, and safety considerations. The primary factors include:

1. Depth of Deposit: Surface mining is generally preferred for shallow deposits or those with a low stripping ratio. As the depth of overburden increases, the cost of removal becomes prohibitive, necessitating a transition to underground methods.
2. Stripping Ratio: This is the ratio of the volume of overburden to the volume of mineral. A low stripping ratio favors surface mining, while a high ratio makes underground mining more economically viable.
3. Nature of Deposit: The geometry, thickness, and dip of the ore body are decisive. Massive, thick, or near-surface deposits are ideal for open-pit mining, whereas thin, deep, or steeply dipping seams often require underground extraction techniques.
4. Geotechnical and Structural Conditions: The stability of the rock mass, presence of faults, and groundwater conditions dictate the feasibility of open-pit slopes versus the support requirements for underground tunnels and stopes.
5. Economic Factors: Capital expenditure (CAPEX) for heavy earth-moving machinery in surface mines versus the development costs for shafts and ventilation in underground mines must be balanced against projected operational expenditure (OPEX) and commodity market prices.
6. Environmental and Social Impact: Surface mining often involves significant land disturbance, noise, and dust, which may be restricted by environmental regulations or proximity to urban areas, potentially forcing the adoption of underground methods.
7. Safety and Productivity: Underground mining typically presents higher inherent risks regarding ventilation, gas, and rock bursts, whereas surface mining offers higher production rates and generally safer working environments.
8. Recovery and Dilution: Surface mining generally allows for higher recovery rates of the ore body compared to underground methods, where pillars must often be left for structural support.