...the tax rate for an incorporated, small-scale mine or mining-related business will be reduced from the former 35 percent rate to 21 percent for the 2018 tax year and thereafter.

First, in order to compensate for the diminishment of purchasing power that usually accompanies rising inflation, investors normally have demanded higher interest rates on their investment assets. This was particularly true in the 1977-81 era when inflation soared to almost 20% and interest rates rose to roughly the same level.