SUTTER CREEK  (AP) — An attempt to unearth new riches from some of the Gold Rush era’s most productive mines has stalled, with the owners saying they must spend more than $1 million before work can resume.

Sutter Gold Mining Inc. said in a statement Tuesday that most work has stopped and non-essential workers have been laid off at the mine in Amador County, about 50 miles southeast of Sacramento.

The company said about 1,000 tons of stockpiled ore was processed before flooding forced the company to shut down operations at the end of February. Operations stopped before it could process the remainder of the 3,500 tons of stored material.

It said the mine will need to remove the water, move equipment and install a gold smelting room before production can resume.