A process is evaluated for recovering metallurgical-grade manganese ore from the low-grade manganiferous iron ores of the Cuyunga Range, Minnesota. The process, developed by the Bureau of Mines, employs high-temperature sulfatization of the ore to form manganese sulfate and reduction of the ore to convert the iron to a magnetic oxide. The roasted ore is water-leached to dissolve the manganese sulfate, which is then separated from the leach residue, crystallized, and calcined to produce the manganese product. Iron is recovered from the leach residue by magnetic separation, and is pelletized and calcined to produce byproduct iron ore pellets. The fixed capital cost for a plant yielding a product containing 100 tons of manganese per day is $19.6 million, on a mid-1970 basis, when the raw ore contains 4.84 percent manganese. The estimated operating cost of the plant is $211 per ton of contained manganese. Graphs are included to show the effects of ore cost and varying manganese content of the raw ore on the estimated operating cost.