What is the term for the rate of increase of rock temperature with increasing depth?

The correct term for the rate of increase of rock temperature with increasing depth is the Geothermal Gradient. This term specifically refers to the increase in temperature per unit of depth in the Earth's crust, typically measured in degrees Celsius per kilometer. Understanding the geothermal gradient is essential in mining as it affects temperature management, safety, and equipment performance at depth.

Thermal gradient, while similar, is a more general term that isn't exclusively linked to geological contexts. Temperature gradient, on the other hand, can refer to any temperature change over distance without the specific geological implications. Heating gradient is not a standard term used in geology or mining. Hence, the Geothermal Gradient is the most precise term for describing how temperature increases with depth in the Earth's crust, making it the most appropriate choice.