The Kuzuu district of Sano City in the southwestern part of Tochigi Prefecture, referred to as “Mining Town Kuzuu,” has one of the Japan's leading and highest quality limestone and dolomite deposits, which are widely distributed in a semicircular shape and belong to the Permian period of the Paleozoic era.
Our company owns the rich ore section of the mine, and we have secured more than one billion tons of ore reserves. The Mitsumine area, Minowa, Ohgano, and Fuji, each have their respective mining areas and are involved in mining, crushing and beneficiating of limestonse and dolomites.
The Bench cut method has been adopted for mining.
The mined ore is first crushed and then transported by conveyor belt or electric locomotive to the dressing plant, where it is washed, crushed, and graded based on the type and application of the ore.

Mt. Mitsumine, at a height of 605 m, straddles the cities of Tochigi, Sano, and Kanuma. As it has a shape resembling a covered pot, it is referred to locally as “Nabeyama.” Mt. Mitsumine is situated at the heart of the Kuzuu district and has a rich supply of ore reserves.
Our company mines an area stretching in the southwestern direction from the peak of the Mt. Mitsumine. It has ore reserves of approximately one billion tons and an area of 240 hectares, approximately 51 times the size of the Tokyo Dome.
Annually, we mine approximately 2.3 M tons of ore from the entire Ohgano mine, of which 70% of is from the Mitsumine area. This area started full-scale ore production in 1974, and by May 2020, had achieved a cumulative output of 100 M tons.

Honzan is located in the northeast of the Kuzuu Plant, where limestones and dolomites are crushed and sorted.
The ores transported from the Mitsumine area are loaded on electric locomotives at the Minowa temporary storage tank and then taken to the ore dressing plant. The supplied ores are then crushed and sorted, and the finished product is loaded for shipment.

Limestones and dolomites ore are processed through calcination, digestion, crushing, mixing, granulation, etc., thus producing products such as quicklime, slaked lime, soft-burned dolomite, calcium carbonate, and magnesium carbonate lime under strict quality control to meet user needs.

Sintering facilities (2 rotary kilns, 2 Mertz shaft kilns)
Fire control equipment, crushing equipment, molding equipment, granulation equipment, and mixing equipment

This plant was established as an on-site plant in 1968 (Showa 43), when Nippon Steel Corporation (then Yawata Iron & Steel) started Kimitsu Steel Works, an integrated steel mill.
As required at Kimitsu Steel Works, we produce and supply quicklime for steelmaking, quicklime for sintering, and lime-based flux materials.
The firing facility has the largest production capacity in our company, at 2,300 tons per day.

The plant includes a firing facility (4 rotary kilns, 1 fluidized bed kiln), a crushing facility, and a mixing facility.

This was purchased from Kanto Steel Manufacturing Co., Ltd. and opened in 1954 to produce low-phosphorus quicklime for steelmaking. Following that, in the 1970s, Asahi Kasei Kenzai Company Limited (at the time, Onoda ALC) launched a plant for producing ALC, after which they shifted to the production of hardened quicklime, which they continue to produce till date.

Sintering facilities (3 standing sintering furnaces)