They do have ear protection. I've seen certain mining facilities where people are required to wear ear protection before entering the farm. This ensures that the employees are not affected by the constant whirring within the facility. This is also mandatory for some datacenters.
if that's the case then i think they might be lying when they claimed that they were not aware of a noise issue! these huge mining facilities really don't do anything for the communities they locate in. they don't serve them in any way. no products no services. just existing to do computations to make a buck. why these local governments would even allow them to set up shop in the first place is mind boggling.