Browns polymetallic ore deposit "sulfide" resources. The oxide resources consist of supergene or weathered sulfide ore where the ore mineralogy is dominated by metal oxides, hydroxides, clays and carbonates after the original sulfide mineralogy. The Browns deposit is currently being developed as a major base metals mine by Compass Resources NL, an Australian public company, in joint venture with Hunan Nonferrous Metals Corporation, a Chinese government company. The mine is due to be complete in August 2008, after suffering cost escalation and construction delays, and will produce 15,000 tonnes of copper, 4,000 tonnes of cobalt and 4,000 tonnes of nickel per annum, with a
Ore extension which means that "δ" is a homomorphism of abelian groups satisfying Then the Ore extension "R"["x";"σ","δ"], also called a skew polynomial ring, is the noncommutative ring obtained by giving the ring of polynomials "R"["x"] a new multiplication, subject to the identity If "δ" = 0 (i.e., is the zero map) then the Ore extension is denoted "R"["x"; "σ"]. If "σ" = 1 (i.e., the identity map) then the Ore extension is denoted "R"["x","δ"] and is called a differential polynomial ring. The Weyl algebras are Ore extensions, with "R" any commutative polynomial ring, "σ" the identity ring endomorphism, and "δ" the