What does mining farm mean?
Big storage house full of mining rigs. These were once primarily in China, but with recent regulatory changes many mining farms in China have shutdown or moved. Russia is a large hub of mining farms also, due to the low cost of electricity, as well as the cold environment.
Cold environments are a positive when building a mining farm because the hardware used generate huge amounts of heat, and when located in a cold environment the mining farm operator can save money on the electricity costs associated with cooling the hardware.