Questions and Answers
What is the primary goal of preventing water from entering a mine?
Which of the following is NOT a source of water in hydrogeology?
When calculating the pressure at the base of a crosscut dammed by water, what density value should be used if given a relative density of 0.8?
Which factor does NOT affect the efficiency of ventilation in a mine?
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What is the expected shape of the water surface in a conical settler when fully operational?
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How does reducing the volume of settler A by 40% impact the total effective settling volume?
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To calculate the size of the displacement rock cavity, what crucial information is necessary?
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In the context of hydrogeology, what does the specific gravity of 0.8 imply for mine water?
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Study Notes
Hydrogeology
- Hydrogeology is the study of the distribution and movement of groundwater in the soil and rocks of the Earth's crust.
- It focuses on understanding how water interacts with geological formations.
Sources of Water
- Surface water bodies (lakes, rivers)
- Groundwater (aquifers, wells)
- Rainfall (precipitation)
Advantages of Preventing Water in Mines
Stability of Working Areas
- Reduced water infiltration enhances structural integrity of mining areas, minimizing risk of collapse.
Costs and Safety
- Decreasing water accumulation reduces operational costs linked to water management systems and increases safety by reducing hazards associated with flooding.
Ventilation Efficiency
- Keeping working areas dry improves air circulation and ventilation, essential for worker safety and health.
Methods to Reduce Water Entry into Mines
- Installation of drainage systems to divert surface and groundwater away from operational areas.
- Use of waterproof barriers and sealants during construction to minimize infiltration.
Calculations Related to the Crosscut Dam
- Dimensions of the crosscut are 1.8m x 1.8m and 5m long, maintained by a 1m wall.
Volume of Water
- Volume contained by dam is calculated using the cross-sectional area and height of water.
Pressure Exerted on Base
- Pressure due to water is calculated based on relative density (0.8), factoring the depth of the water column.
Pressure with Reduced Dam Capacity
- If dam is 85% full, pressure calculations adjust based on the new water height.
Force on Dam Wall
- The force exerted on the wall of the dam is determined using the pressure at the base and the area of the wall.
Conical Settler Calculations
- Each settler has a diameter of 0.8m, with a distance of 1.25m between the top of the settler and water level, with the water level at 0.5m high.
Single Settler Volume
- Volume of a conical settler computed using geometric formulas for cones, factoring in the height and radius.
Effective Settling Volume
- In series connection, the effective volume is reduced as per the percentage reductions for each settler A, B, and C.
Displacement Rock Cavity Size
- To settle 50µ particles from mine water with specific gravity of 0.8 and flow rate of 200m³/hr, the diameter of the required cavity is calculated considering efficiency (90%).
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Description
This quiz explores the fundamentals of hydrogeology, focusing on water sources and the advantages of water management in mining operations. Key concepts such as stability, costs, and safety are discussed, helping to deepen understanding of mine hydrology.