All mines whose gross proceeds during the preceding calendar year have exceeded the amount of five thousand dollars shall be classified as producing mines, and all others shall be classified as nonproducing mines. Mines shall be classified in the manner provided for in this article regardless of the processing method, the ultimate use, or the consumption of the ores or minerals for which they are primarily worked or operated.
Source: L. 65: R&RE, p. 1102, § 1. C.R.S. 1963: § 137-6-4.