Mine Water Management: Hydrogeology Q&A

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%).