Environmental Engineering and Bulk Air Cooling in Mines

This set of flashcards covers bulk air cooling methods, design considerations, and specific heat load calculations for O.F.S. gold mines as described in the lecture materials.

What are the two primary consequences of tube fouling in cooling systems?

It reduces the space inside the tubes and decreases the ability of heat removal.

What are the six design considerations for Bulk Air Cooling methods?

1. Pumping costs, 2. Volume of air to be cooled, 3. Positional efficiency, 4. Size of excavation, 5. Optimization of total owning costs.

What are the two types of Bulk Air Cooling methods mentioned?

Cascade Cooler (used in cooling cars) and Horizontal Spray Chambers (2 stage cooling).

What is the specific heat capacity of water ($C_{pw}$) used in mine heat load calculations?

$$4.187\,kJ/kg^{\circ}C$$

What is the formula used to calculate the heat added by fissure water ($q$)?

$$q = M \times C_{pw} \times (VRT - \text{reject temperature})$$

In the O.F.S. air requirements for Zone 1, what is the temperature of the 1st critical horizon?

$$27^{\circ}C$$

Based on Figure 38.5, what is the heat load prediction for a virgin rock temperature (VRT) of $47.5^{\circ}C$ and a distance of $2500\,m$ from the shaft?

$176\,kW$ per $1000$ tons per month.

What correction factor is applied to the heat load for a reject temperature of $27^{\circ}C$?

A correction factor of $+12\%$ is added.

In the example provided, what is the total mine heat load calculation if the production rate is $150$ (kton/month) and the heat production rate is $197\,kW/1000$ tons per month?

$$197 \times 150 = 29550\,kW$$

In the example calculation for fissure water heat, what was the result given a mass flow of $15\,kg/s$, VRT of $47.5^{\circ}C$, and a reject temperature of $27.0^{\circ}C$?

$$1288\,kW$$

What is the total combined heat load in the example involving both mine heat load and fissure water heat?

$$29550 + 1288 = 30838\,kW$$

What are the typical air mass flow rate units used in the O.F.S. Figure 38.4 chart?

$$kg/s/k\,ton / month$$