The firm said it is also conducting a study to see about increasing the mill throughput by about 25% to continue with steady gold production as grades are expected to decline slightly in the future.
The National Trust thinks the internal workings were substantially altered in about 1840 to allow the millto grind wheat, having previously ground oats.
Late Tuesday morning, police responded to a call from maintenance staff at the Mill Run at Union Apartments in Union Township, about seven miles southwest of Newark.