Mine Water Settling Calculations

Study Notes

Conical Settler Volume Calculation

Volume of a conical settler can be derived using the formula: ( V = \frac{1}{3} \pi r^2 h ), where ( r ) is the radius and ( h ) is the height of the cone.
Effective settling volume is influenced by the reduced volumes of connected settlers:
- Settler A reduced by 40%
- Settler B reduced by 25%
- Settler C reduced by 10%

Displacement Rock Cavity Size

Size of the displacement rock cavity depends on the flow of mine water at a rate of 200 m³/hr.
For settling 50µ particles and water with specific gravity of 0.8, calculate volume using Stokes' law for settling particles.
With 90% efficiency, use the equation relating the volume flow rate to the cavity dimensions to determine diameter of the circular cavity.

Sump Location Factors

Consideration of surrounding geology and hydrology to prevent flooding.
Accessibility for maintenance and emergency evacuations.
Location relative to the site of water collection and transportation needs.

Masonry Dam Load Analysis

The load on a masonry dam is determined using hydrostatic pressure formula: ( P = \gamma h ), where ( \gamma ) is specific weight of water (approximately 9.81 kN/m³).
For an arc of a circle with radius 30m subtending an angle of 60°, calculate load in N/m length at different heights.
The position of the line of action can be found by determining the center of pressure, leveraging geometric relationships within the arc.

Bridge Arch Calculations

The upward force on the underside of a semi-circular arch can be analyzed using hydrostatic pressure: ( F = \gamma V ).
For bridge arch width of 4m and 1.25m water above crest, compute the vertical forces acting on the structure.
Analyze horizontal thrust using principles of equilibrium and geometry specific to arches.

Fluid Flow and Energy Equation

Energy equation between two points in a frictionless pipe includes terms for potential energy (height), pressure energy, and kinetic energy: ( \frac{P_1}{\gamma} + z_1 + \frac{v_1^2}{2g} = \frac{P_2}{\gamma} + z_2 + \frac{v_2^2}{2g} ).
Assumptions of Bernoulli's equation include:
- Steady flow
- Incompressible fluid
- No friction losses
Use given parameters to calculate discharge at B and the energy loss due to friction between points A and B, considering height differences and pressure heads.

Description

This quiz focuses on calculating the volume of conical settlers and determining the effective settling volume when varying sizes are connected in series. Additionally, it covers the calculation of the required size of a displacement rock cavity for settling fine particles in mine water. Test your knowledge on settling processes and engineering principles.