Caves and mines are dark, so light is definitely the single most important problem to solve when you want to enter them. Light is such an important topic we started to sort the different aspects into groups, to make them easier to understand.
The use of light by speleologists is important, and actually a rather young problem. Real scientific cave research started only 150 years ago. And since then the lights used for caving were continually developed. While we all depend on scientific and industrial development, the cavers always tended to customize bleeding edge technology for their needs.
As light is essential for a save caving trip, it is absolutely necessary to take several light sources with you. If possible, take different kinds of light with you, they may have different pros and cons. So if it is too windy for a carbide lamp, the electric light will still work. But if the tour takes very long, it would be hard to carry enough spare batteries.
Show caves have different requirements for light than individuals, becuase the light is installed and not mobile. On one side the energy is available in large amounts, as it is possible to install electric wires. On the other hand the light must be on for a long time, must be easy to handle, and should require a minimum of maintenance. This collides with the wet surrounding, the water is slightly acidic and things which are stainless outside are corroded after months or even weeks.
Mining is much older than cave exploration. It actually started in prehistoric times. Miners used candles and oil lamps in various versions. Those were the only available light sources, and the fuel was easy to harvest. Later the needs of the industrial revolution pushed the development of new light sources, like carbide lamps, but also the security problems related with mines. For example, for the use in coal mines security lamps were developed, which did not ignite possible explosive gases.
This is the rest, anything which does not fit into above three categories.