Mine Ventilation Psychrometry and Heat Theory

Vocabulary flashcards covering psychrometric definitions, total heat components, air standard states, and key heat sources in underground environments based on lecture notes.

Sigma Heat

The total heat enthalpy of air (in $kJ/kg$) minus the enthalpy of the liquid at the atmospheric wet-bulb temperature.

Vapour Pressure ($e$)

The partial pressure of the water vapour present in a sample of air.

Saturated Vapour Pressure (SVP)

The partial pressure exerted by water vapour when a sample of air is saturated.

Enthalpy

The sum of all sensible heat, latent heat, and superheat of a sample of air calculated above an arbitrary datum of $0^\circ C$, expressed in $kJ/kg$.

Gauge Pressure

The amount by which the actual pressure differs from atmospheric pressure.

Standard Air

Air defined as having a true density of $1,2\,kg/m^3$.

Free Air

Air defined as having a true density of $1,0\,kg/m^3$.

Normal Temp & Pressure (NTP)

Standard environmental conditions defined by a temperature $T = 0^\circ C$ and a pressure $P = 1011, 325\,kPa$.

Atmospheric Pressure

The sum of all individual partial pressures.

Major Sources of Underground Heat

The two primary categories of underground heat sources: heat flow from rock and heat from machinery.

Virgin Rock Temp (VRT)

The natural temperature of unmined rock that, along with the production rate (tons broken per month), primarily drives the rate of heat flow from exposed and broken rock into ventilating air.

Excavation Age and Heat Influx

The physical relationship where the rate of heat influx into an excavation is inversely proportional to the age of the excavation.

Heat Generation in Lifting Machinery

Heat produced during vertical lifting operations (such as hoisting or pumping), where most energy is converted to potential energy and only the energy lost to inefficiency becomes heat.

Heat Generation in Horizontal Transport

Heat produced when transporting material horizontally or operating fans, where all work is done to overcome friction, converting all consumed energy directly into heat.

Heat Generation in Diesel Machinery

Heat production that is calculated as a function of the fuel consumption rate and the calorific value of that fuel.