Fertilizer factory (1943-1945)
A flotation plant to extract fertilizer from the apatite rich mine sludge was built in co-operation with the Ministry of Agriculture in 1943. From 1943 to 1945 the plant treated 220,000 tons of sludge, and gave 5825 tons of concentrate containing 27.5 % phosphate. The concentrate was then shipped to Lysaker Chemical Factory (Oslo) for further treatment.
The project was considered a failure. The factory was closed in 1945, at the end of World War II.