Six companies with 12 processing facilities in 4 States produced diatomite. California and Nevada were the principal producing States. The United States remained the largest producer and consumer of diatomite and exported processed diatomite to more than 50 countries, primarily for filtration use.
All domestic mining is by open pit, and challenging land use problems exist.
Control of dust in mining is assisted by the high moisture content of the crude ore. Effective control of silica dust in processing is facilitated by enclosure of the process. However, the unique properties of diatomite assure its continuing use for many applications. Expanded perlite, asbestos, and silica sand compete for filtration purposes, although, in most instances, diatomite is a superior material. Alternate filler materials include talc, ground silica sand, ground mica, clay, perlite, vermiculite, and ground limestone.