Note 2 - Estimated Useful Lives of Property, Plant and Equipment (Details)	12 Months Ended
	Dec. 31, 2015
Land Improvements [Member]
Property, Plant and Equipment, Estimated Useful Lives	Estimated life of mine
Building Improvements [Member] | Minimum [Member]
Property, Plant and Equipment, Useful Life
Building Improvements [Member] | Maximum [Member]
Property, Plant and Equipment, Useful Life
Building Improvements [Member]
Property, Plant and Equipment, Useful Life	15 years
Mine Development [Member] | Minimum [Member]
Property, Plant and Equipment, Useful Life	3 years
Mine Development [Member] | Maximum [Member]
Property, Plant and Equipment, Useful Life	5 years
Mine Development [Member]
Property, Plant and Equipment, Useful Life
Vehicles [Member] | Minimum [Member]
Property, Plant and Equipment, Useful Life
Vehicles [Member] | Maximum [Member]
Property, Plant and Equipment, Useful Life
Vehicles [Member]
Property, Plant and Equipment, Useful Life	5 years