The quake damaged some of the older buildings in the region, and schools will be closed for the day for safety checks.
Locals say they are worried about further tremours.
'Several aftershocks'
"It was going for about a good 20 seconds and we've felt several aftershocks, so we might not be in the clear yet," Kalgoorlie Miner newspaper journalist Nick Rynne told Sky News.
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Police cordoned off parts of Boulder, a remote town about 600 kilometres east of Perth, and mine operator KCGM said Super Pit and Mount Charlotte would be closed for several hours.
"The evacuation is purely a precautionary measure," a spokeswoman told AFP. "We haven't sustained any damage and all personnel are safe.
"But we do have our geotechnical team there at the moment, assessing the situation."
Two people have minor injuries resulting from the quake.
It struck with a magnitude of 4.8 at 8.17am (WST) on Tuesday, Geoscience Australia said.
State Premier Colin Barnett said it was quite a strong earthquake.
School closed as precaution
"There's been some structural damage to some schools," he told reporters in Canberra during a break in a COAG meeting on health reform.
"They've been closed for the day just to check the safety."
"Western Australia can be prone to earthquake and this is an example," he said.
