EM 10 - 11 Mining Method Selection (Part 1)

Summary

This video introduces the process of selecting mining methods, focusing on key factors that influence decisions. It covers the classification system for mining methods, factors affecting the choice between surface and underground mining, and how deposit size, shape, and geologic conditions impact the selection. The video also explains the importance of selectivity, hydrology, and geotechnical properties. Visual aids and examples are provided to help illustrate concepts. The lesson ends with a discussion on rock support methods and the relevance of geotechnical characteristics in mining operations, encouraging viewers to continue with part two for more details.

Takeaways

• 🛠️ Mining method selection depends on understanding key factors, such as ore body characteristics.
• 📊 There are two main classifications of mining methods: surface and underground, and both are influenced by ore characteristics.
• 🔍 The purpose of a classification system for mining methods is to guide the selection of the most suitable method for specific ore bodies.
• 📐 Spatial characteristics like size, shape, depth, and regularity of ore deposits are crucial for determining mining methods.
• 🌍 Surface mining is often used when ore deposits are closer to the surface, while underground mining is preferred for deeper deposits.
• 💧 Geologic and hydrologic factors, including groundwater presence, mineralogy, and selectivity, influence mining method selection.
• 🏗️ Geotechnical properties, including soil and rock mechanics, affect the choice of mining equipment and safety measures.
• 🛡️ Rock support structures, such as rock bolts and timber sets, are necessary to prevent cave-ins in underground mining.
• ⚒️ There are three main underground mining methods: unsupported, supported, and caving, each used based on rock stability.
• 📚 Understanding geotechnical properties like elasticity, stress state, and plastic behavior is essential for safe mining operations.

Q & A

What is the main purpose of having a classification system for mining methods?

The classification system for mining methods serves two purposes: to provide initial guidelines for selecting suitable mining methods based on ore characteristics, and to guide future decisions regarding safety, economy, and environmental considerations for mine design.

What factors are considered in selecting a mining method?

Factors include spatial characteristics of the deposit (size, shape, regularity, depth), geologic and hydrologic conditions (selectivity, hydrology, mineralogy), geotechnical properties (soil and rock mechanics), and previous mining history.

Why might a surface mining method be used for a nickel deposit but an underground method for a copper-gold deposit?

A surface mining method is used for the nickel deposit because it is closer to the surface, while an underground method is used for the copper-gold deposit because it is located deeper below the surface.

What is 'selectivity' in the context of mining methods?

Selectivity refers to the ability of a mining method to extract the ore while minimizing or avoiding the extraction of waste material.

How do hydrology and mineralogy affect mining method selection?

Hydrology, the movement of water in relation to land, affects drainage and pumping requirements, while mineralogy, the study of minerals’ physical and chemical properties, influences mineral processing, solution mining, and smelting decisions.

What role do spatial characteristics of an ore body play in choosing a mining method?

Spatial characteristics, such as the size, shape, and depth of the ore body, are critical in determining whether surface or underground mining is more appropriate and in influencing the overall mine layout.

What geotechnical properties are important in selecting a mining method?

Geotechnical properties such as soil and rock mechanics, the elastic and plastic behavior of the rock, and the state of stress are key in determining both the equipment used and the underground method (unsupported, supported, or caving) for mining.

What is the importance of understanding 'planes of weakness' in mining?

Understanding planes of weakness, such as fractures in the rock, is crucial for deciding whether the mining method needs ground support and for ensuring the stability and safety of the mine.

Why is groundwater a concern in mining, and how is it managed?

Groundwater can interfere with mining operations, affecting drainage and creating the need for pumping. Proper hydrological management ensures that water is safely removed from the mining area, preventing flooding and ensuring smooth operations.

What are some examples of mining supports, and why are they necessary?

Examples include rock bolts and timber sets. These supports are necessary to prevent the collapse of underground excavations, ensuring the safety of miners and the stability of the mine structure.