Pull air out and push cold air in is the best option, if you only have 1 fan then, pull the hot air out, cold air will be pulled in from any unsealed paths.
I don't fully agree with this but it does depend on the size of your mining operation. I have 200 GPUs in a 1800 sqft warehouse and initially due to lack of air flow/moving air, the air temperature rose to almost 50C... and this was with two exhaust fans pulling air out.
Changing the setup to have one intake fan resolved the problem and air temperatures inside now a happy 30C.
Thats very interesting and maybe i am wrong on this occasion. I am not sure where the hot air would be going if you are only blowing colder air in
Sorry, I meant that I added one intake fan as well as the two exhaust/out fans and that solved the problem.. Without the intake fan, there was no moving air and temperature just went up and up... 50C inside is pretty hot and the paint started melting on the walls.. No fires though

Hmmm i have a similar amount of gpu running in my facility. In one of the hottest country in asia also.
My exhaust fans doing wonders for me at the moment. But i do have big louvers for air intake. But no intake fans. Only exhaust fans to keep the hot air out while pulling fresh air in.
Also 50C is hot? For a gpu farm? To the point paint is melting off the walls? Thats crazy. At night my coolest temp for my cards are just under 50C. Hottest is just below 70C in thr afternoon.
Maybe im running my gpu side of the facility too hot.
*edit nevermind. Your talking about ambient room temp.

, does sound like a sauna in there.