Ann: Positive Metallurgical Test Results - Halleck Creek Project, page-15

Amigos, this news is fantastic - the type of news I have been hoping for. From the State of Nevada Department of Conservation and Natural Resources (Division of Environmental Protection): "Leaching is a relatively low cost and common process that uses chemicals to dissolve the desiredmetals from the ore for subsequent recovery. ...The most common methods for recovery of base metals (copper, lead, and zinc), include frothflotation and acid leaching. Acid leaching with sulfuric acid is performed on lined heap leach pads". So ARR's announcement fits well with currently accepted views about environmental protection in mining industries in the USA. The fact is it is a standard, well-accepted, commonly used process. Also, sulphuric acid is fairly cheap (a web search shows it ranges between US$80 to 120 per ton) and (as stated in the announcement) the open vats/tanks are not pressurised, so there will be no need for expensive, high-maintenance, large autoclaves (ie no need for massive stainless steel pressure-cookers). Also the announcement said that there will be no need for flotation processes, so no need for this extra step and no need of solvents. The sulphuric acid basically flows from one tank to the next, becoming more concentrated with rare earth metals as it goes (ie becoming pregnant with REOs). So simple, with no spill or wastage:
"In tank leaching the ground, classified solids are already mixed with water to form a slurry or pulp, and this is pumped into the tanks. Leaching reagents are added to the tanks to achieve the leaching reaction. In a continuous system the slurry will then either overflow from one tank to the next, or be pumped to the next tank. Ultimately the “pregnant” solution is separated from the slurry using some form of liquid/solid separation process, and the solution passes on to the next phase of recovery. (from Wikipedia) ".