Ultramafic

There is some beneficiation of talc by froth flotation (qv), practiced especially on ultramafic-type deposits. In this process (Fig. 2), talc is milled to its hberation size (—100 mesh (ca 0.15 mm)) using ball mills or ring-type roUer mills and then slurried at 10—30% in water. Flotation is done in conventional multistage float cells using methyl amyl alcohol as a frother. Typically two to four stages are required to upgrade the ore from 50—70% talc to 90—98%. The product is filtered and then flash-dried and milled to a final product. 

Feux, A. N. and Baker, D. R. (1973). Stable carbon isotopes in selected granitic, mafic, and ultramafic igneous rocks. Geochim. Cosmochim. Acta 37, 2509-2521. 

Valuable mineral deposits which form by residual concentration pertain to iron, manganese, aluminum, nickel, clays, tin and gold. Aluminum comes almost exclusively from residual concentrations of bauxite, which result from the laterihsation of alumina rich igneous rocks like syenites under tropical and subtropical climatic conditions. Laterites also contribute nearly 80% of the world s reserves of nickel at grades better than 1% Ni. They form by residual concentrations as a result of weathering of mafic and ultramafic igneous rocks, which are relatively enriched in nickel. 

Northern Californian soils have higher concentrations of Cr, Co, Cu and Ni than southern California since there are volcanic ultramafic rocks in northern California. Ultramafic rocks are mostly serpentine, a magnesium silicate with associated high amounts of Ni and Cr. Soils formed on serpentine parent materials contain high to extremely high Ni and Cr concentrations in soils. Soil parent material is a factor mostly controlling trace element concentrations in soils. 

In addition to anthropogenic pollution, some serpentine soils derived from Fe and Mg-rich ultramafic rocks are enriched in Ni, Cr and Co. In North America, ultramafic rocks form two discontinuous bands along the east and west side of the continent. The largest area of ultramafic terrain is in the Klamath Mountains province of northern California and southern Oregon (Lee et al., 2001). Serpentinite is a metamorphic rock formed from low... 

Worldwide distribution of magnesium-rich ultramafic rocks. 

Goff, F. and Lackner, K.S., Carbon dioxide sequestering using ultramafic rocks, Environ. Geosci., 5(3), 89,1998. 

Crowflight Minerals Inc. The ore deposit consists of Aphebian ultramafic sills intruded into Archean gneisses (Wardrop 2008). Rougher tails were produced from lock cycle testing of bulked drill core samples. 

Carbon mineralization in mine tailings and implications for carbon storage in ultramafic-hosted aquifers... 

ABSTRACT Atmospheric carbon dioxide is trapped within magnesium carbonate minerals during mining and processing of ultramafic-hosted ore. The extent of mineral-fluid reaction is consistent with laboratory experiments on the rates of mineral dissolution. Incorporation of new serpentine dissolution kinetic rate laws into geochemical models for carbon storage in ultramafic-hosted aquifers may therefore improve predictions of the rates of carbon mineralization in the subsurface. 

Freyssinet, P. Farah, A.S. 2000. Geochemical mass balance and weathering rates of ultramafic schists in Amazonia. Chemical Geology, 170, 133-151. 

Wilson, S.A., Dipple, G.M., Power, I.M. et al. 2009. Carbon dioxide fixation within mine wastes of ultramafic-hosted ore deposits Examples from the Clinton Creek and Cassiar chrysotile deposits, Canada. 

Our results demonstrate significant spatial differentiation in the geochemistry of Sacramento Valley soil between the eastern and western sides of the valley that is related to the geomorphic separation of the valley by a levee along the Sacramento River. The western valley contains an elevated component of material derived from ultramafic rocks compared to the eastern side. 

This east-west difference reflects dominance in sediment source in the eastern valley by material derived from glacial debris and placer mining, and the presence of ultramafic rocks in the headwaters of western streams and ultramafic constituents in sediments on the west side of the valley. 

The Expo Intrusive Suite is for the most part composed of mafic and ultramafic intrusions, shaped as tabular-shaped discordant bodies, so are referred as dykes. The Expo suite is economically important due to the presence of sulfide mineralization in the internal part of the intrusion. It is composed of gabbro norite, pyroxenite, peridotite, and dunite. 

The major geological boundaries correspond with sharp changes in the selective extraction geochemical patterns (Fig. 1). The Troodos ultramafics are characterised by much higher AAC-... 

The Ulsan carbonates (Fig. 1) have long been interpreted as limestone of Paleozoic age or "age unknown" and as the host of a skarn-type iron (magnetite) deposit due to the intrusion of Cretaceous granitic rocks (Park Park 1980 Choi et al. 1999). However, a Paleozoic marine limestone hypothesis fails to explain the spatial association or the relationship between carbonate and ultramafic rocks in a concentric, ellipsoidal shape surrounded by Cretaceous sedimentary, volcanic, and granitic rocks. The sedimentary hypothesis also fails to explain the isolated exposure of a funnel-shaped Paleozoic marine limestone where no marine limestone has been previously observed within the Mesozoic Kyongsang Basin. 

Geological Setting The geology of the study area consists of Cretaceous sedimentary, volcanic, granitic, ultramafic (serpentinite), and carbonate rocks containing a magnetite-rich pipe and basic dykes (Fig. 1). The sedimentary rocks are intruded by felsic volcanic, granitic and ultramafic rocks,... 

The geology of Cyprus is dominated by four distinct terranes - the Troodos Ophiolite Complex composed of mafic and ultramafic rocks, the Circum-Troodos Sedimentary Sequence containing calcarenites, siltstones and carbonates, the Mamonia Complex composed of igneous, sedimentary and metamorphic rocks and the Kyrenia Terrain containing a series of allochthonous massive and recrystallised limestones dolomites and marbles. These terranes generate highly varied landscapes (Fig 1). 

The Stillwater Complex consists of a sequence of differential layers of mafic and ultramafic rocks, which extend for a strike length of up to 40 km and has a maximum exposed thickness of about 7.4 m [3], There are several mineralization zones at the Stillwater Complex, including a PGM-rich zone and a low-grade zone. The Stillwater ore that is processed nowadays contains olivine, plagioclase, as well as plagioclase-brauzite, all of which are naturally hydrophobic gangue minerals. 

Xenoliths from Siberian continental lithosphere, with Archean model ages, had b Li as low as +0.5 (Eouman et al. 2000). If these values accurately represent the Archean mantle, they suggest the potential for Li isotopic evolution in the Earth, from lighter compositions in the ancient mantle to what is seen in present-day MORE. In spite of the analytical challenges presented by ultramafic rocks, more data from these materials are crucial to an understanding of Li in the mantle, and in resolving questions about the appropriateness of the accepted MORE mantle range. 

Schauble EA, Rossman GR, Taylor Jr. HP (2003) Theoretical estimates of equilibrium chlorine-isotope fractionations. Geochim Cosmochim Acta 67 3267-3281 Sharpe MR, Hulbert LJ (1985) Ultramafic sills beneath the eastern Bushveld Complex Mobilized suspensions of early Lower Zone cumulates in a parent magma with boninitic affinities. Econ Geol 80 849-871 Sie PMJ, Frape SK (2002) Evaluation of the groundwaters from the Stripa mine using stable chlorine isotopes. Chem Geol 182 565-582... 

Chromium is a compatible element in the Earth s mantle, and tends be present in much greater concentrations in mafic igneous rocks than in felsic ones (Faure 1991). Ultramafic rocks often contain over 1,000 ppm Cr and can generate environmental problems when they weather (Robertson 1975 Robles and Armienta 2000). Granites may contain less than 20 ppm Cr, whereas shales contain roughly 90 ppm. 

Chemical Units Seawater Overall Slow Intermediate Fast Ultrafast Sediment Ultramafic Arc,... 

Enstatite-bronzite (MgTel Si O, Gabbros Mg-iich ultramafic rocks serpentinites meteorites... 

---