Final answer:
The temperature generally increases as you travel deep into a mine shaft, due to the geothermal gradient and the heat from the Earth's core. The rate of increase can vary, but is often about 1°C for every 30 meters in depth.
Step-by-step explanation:
As you travel deep into a mine shaft, the temperature generally increases. This phenomenon is due to the geothermal gradient, which is the rate at which the Earth's temperature rises with depth, primarily due to the heat emanating from the planet's core. The deeper you go, the closer you get to the Earth's internal heat sources, and thus the temperature tends to rise.
There might be variations depending on the mine's ventilation and the presence of water, but typically, the increase in temperature is an expected trend. This is quite different from the earth's atmosphere, where temperature can decrease with altitude, an effect most notably observed in the troposphere. The exact rate of temperature increase can vary, but a common value is an increase of about 1°C for every 30 meters (100 feet) in depth, though this can be influenced by local geological conditions.