on october 13, 2010, 3m completed acquisition of arizant inc. in december 2011, 3m completed the acquisition of the winterthur technology group, a bonded abrasives company. as of 2012, 3m was one of the 30 companies included in the dow jones industrial average, added on august 9, 1976, and was 97 on the 2011 fortune 500 list.
early mining ventures, having relatively unsophisticated methods, often could not achieve a high degree of separation, so significant quantities of minerals found their way into the waste mineral dumps of mines. as the value of a mineral increases, or when new and cheaper means of processing the gangue to extract the ore are introduced, it may become worthwhile to rework such old dumps to retrieve the minerals they still contain.
magnetic separation is the process of separating components of mixtures by using magnets to attract magnetic materials. the process that is used for magnetic separation detaches non-magnetic material with those who are magnetic. this technique is useful for not all, but few minerals such as ferromagnetic .
prospecting is the first stage of the geological analysis second – exploration of a territory. it is the physical search for minerals, fossils, precious metals or mineral specimens, and is also known as fossicking.. prospecting is a small-scale form of mineral exploration which is an organised, large scale effort undertaken by commercial mineral companies to find commercially viable ore .
monazite can be isolated as a nearly pure concentrate by the use of gravity, magnetic, and electrostatic separation. monazite sand deposits are inevitably of the monazite- ce composition. typically, the lanthanides in such monazites contain about 45–48% cerium , about 24% lanthanum , about 17% neodymium , about 5% praseodymium , and minor quantities of samarium , gadolinium , and yttrium .
because of their high density, monazite minerals concentrate in alluvial sands when released by the weathering of pegmatites.these so-called placer deposits are often beach or fossil beach sands and contain other heavy minerals of commercial interest such as zircon and ilmenite.monazite can be isolated as a nearly pure concentrate by the use of gravity, magnetic, and electrostatic separation.