Time filter

Source Type

Melbourne, Australia

BHP Billiton is an Anglo-Australian multinational mining, metals and petroleum company headquartered in Melbourne, Australia. It is the world's largest mining company measured by 2013 revenues.BHP Billiton was created in 2001 through the merger of the Australian Broken Hill Proprietary Company Limited and the Anglo–Dutch Billiton plc. The result is a dual-listed company. The Australia-registered BHP Billiton Limited, which has equal financial share in the company, has a primary listing on the Australian Securities Exchange and is the largest company in Australia measured by market capitalisation. The UK-registered BHP Billiton Plc has a primary listing on the London Stock Exchange and is a constituent of the FTSE 100 Index. It had a market capitalisation of approximately £41.5 billion as of 19 August 2014. On August 19, 2014, BHP Billiton announced the company would be split in two. A newly formed entity named South32 will house the company's non-core assets. Capitalized at $15 billion, the new entity will be listed on the Australian Securities Exchange with a secondary listing on the Johannesburg bourse and a standard listing on the London market. Wikipedia.

Nimis P.,University of Padua | Nimis P.,CNR Institute of Geosciences and Earth Resources | Grutter H.,BHP Billiton
Contributions to Mineralogy and Petrology | Year: 2010

Mutual relationships among temperatures estimated with the most widely used geothermometers for garnet peridotites and pyroxenites demonstrate that the methods are not internally consistent and may diverge by over 200°C even in well-equilibrated mantle xenoliths. The Taylor (N Jb Min Abh 172:381-408, 1998) two-pyroxene (TA98) and the Nimis and Taylor (Contrib Mineral Petrol 139:541-554, 2000) single-clinopyroxene thermometers are shown to provide the most reliable estimates, as they reproduce the temperatures of experiments in a variety of simple and natural peridotitic systems. Discrepancies between these two thermometers are negligible in applications to a wide variety of natural samples (≤30°C). The Brey and Köhler (J Petrol 31:1353-1378, 1990) Ca-in-Opx thermometer shows good agreement with TA98 in the range 1,000-1,400°C and a positive bias at lower T (up to +90°C, on average, at T TA98 = 700°C). The popular Brey and Köhler (J Petrol 31:1353-1378, 1990) two-pyroxene thermometer performs well on clinopyroxene with Na contents of ~ 0.05 atoms per 6-oxygen formula, but shows a systematic positive bias with increasing Na Cpx (+150°C at Na Cpx = 0.25). Among Fe-Mg exchange thermometers, the Harley (Contrib Mineral Petrol 86:359-373, 1984) orthopyroxene-garnet and the recent Wu and Zhao (J Metamorphic Geol 25:497-505, 2007) olivine-garnet formulations show the highest precision, but systematically diverge (up to ca. 150°C, on average) from TA98 estimates at T far from 1,100°C and at T < 1,200°C, respectively; these systematic errors are also evident by comparison with experimental data for natural peridotite systems. The older O'Neill and Wood (Contrib Mineral Petrol 70:59-70, 1979) version of the olivine-garnet Fe-Mg thermometer and all popular versions of the clinopyroxene-garnet Fe-Mg thermometer show unacceptably low precision, with discrepancies exceeding 200°C when compared to TA98 results for well-equilibrated xenoliths. Empirical correction to the Brey and Köhler (J Petrol 31:1353-1378, 1990) Ca-in-Opx thermometer and recalibration of the orthopyroxene-garnet thermometer, using well-equilibrated mantle xenoliths and TA98 temperatures as calibrants, are provided in this study to ensure consistency with TA98 estimates in the range 700-1,400°C. Observed discrepancies between the new orthopyroxene-garnet thermometer and TA98 for some localities can be interpreted in the light of orthopyroxene-garnet Fe 3+ Partitioning systematics and suggest localized and lateral variations in mantle redox conditions, in broad agreement with existing oxybarometric data. Kinetic decoupling of Ca-Mg and Fe-Mg exchange equilibria caused by transient heating appears to be common, but not ubiquitous, near the base of the lithosphere. © Springer-Verlag 2009.

The Leinster area is situated toward the southern end of the Agnew-Wiluna Belt in the Yilgarn craton of Western Australia and hosts the giant Perseverance komatiite-associated nickel sulfide deposit. At in excess of 1.2 Mt contained Ni, this is the biggest type 1 (basal sulfide-rich accumulation) deposit in the world, and it is associated with a number of smaller deposits that extend over a strike length of 20 km adjacent to the Perseverance fault on the eastern margin of the belt. In broad terms, the greenstone sequence comprises an eastern, rift-proximal komatiite-dacite sequence and a western and more marginal basalt-dominated sequence with minor komatiite. The komatiites display a wide range of compositions and textures, from highly magnesian, olivine meso- to adcumulate rocks composed of olivine with forsterite contents of up to 94.5% to sequences of thin, spinifex-textured komatiite flow units. This compositional range indicates considerable variation in volcanic facies, from rift-proximal to distal. Loci of focused flow (termed pathways), indicated by thickened cord-like bodies of more olivine rich rock, occur at all scales and are intimately associated with the Ni sulfide mineralization. The pathways are linked by thinner sequences of lower-MgO rocks, either layered olivine orthocumulate rocks or sequences of thin spinifex-textured flow units. Some of the lower-MgO komatiite sequences appear to emanate from the tops of pathways, in the manner of breakout flows in tube-fed basaltic terrains. Variably sulfidic black shales and cherts and barren exhalative iron sulfide horizons are intimately interlayered with the komatiitic rocks. The overprinting effects of regional deformation and metamorphism, spanning at least 80 m.y., are considerable. At least eight local deformation events have been recognized by previous workers. These have been used to constrain the 3-D model and can be linked to craton-wide structural schemes. Some of the major faults are clearly accretionary and reflect reactivation of underlying basin-forming structures. Early north-over-south thrusting was followed by E-W-directed basin closure and the development of NNW-trending open regional folds. Extension accompanied batholithic granitoid intrusion and reactivated rift-parallel NNW-trending faults, producing the major strike-slip fault systems that divide the greenstone succession into a series of structural and stratigraphic domains. The ensuing orogenic collapse resulted in overturning of the stratigraphy to the east. Subsequent brittle deformation events have produced fault sets in a variety of orientations that can be related to ongoing shortening with a variable principal stress orientation. There is a complex interplay of structural and volcanological controls on the formation and subsequent deformation of the Ni sulfide deposits in this ancient terrane. Three-dimensional modeling has furthered a detailed understanding of the geologic and structural evolution of the belt, allowed the identification of komatiite pathway positions and their plunges, and provided quantitative data on the magnitude and direction of fault offsets of different generations. The modeling exercise has shown that it is possible to strip away the effects of overprinting metamorphism and deformation to reveal some of the primary controls on komatiite volcanism and the location of Ni sulfide deposits, even in those portions of greenstone belts that are highly deformed and have undergone amphibolite facies metamorphism. This is illustrated with case studies of the Perseverance, Venus, Rocky's Reward, Harmony, and Sir Lancelot deposits. Three-dimensional modeling has the capacity to integrate geologic, geochemical, and geophysical datasets in a way that fully utilizes the results of past exploration programs and produces a premium geologic product that can be used to guide further exploration. The recent discovery of the Venus deposit is, in part, a tribute to the power of this approach. ©2015 Society of Economic Geologists, Inc.

The Yakabindie area hosts significant deposits of disseminated Fe-Ni-Cu sulfide in the Six Mile Well (∼2.0 Mt contained Ni) and Goliath North (∼0.6 Mt contained Ni) dunite lenses. These dunite lenses form part of the same komatiitic ultramafic unit that hosts the giant Mount Keith MKD5 deposit (>2.6 Mt contained Ni) to the north, but the morphology and internal stratigraphy of the host unit differs significantly. Three-dimensional modeling of the Yakabindie region reveals that each dunite lens is located at the intersection between steeply dipping NNW- and NNE-trending synvolcanic faults, which appear to have acted as conduits from which komatiitic lava vented onto the seafloor. The igneous contacts dip more shallowly to the west and describe a W-facing wedge of olivine-cumulate rock, probably less than 1 km in plunge extent and cored by adcumulate rock. The mineralization at both Six Mile Well and Goliath North consists of multiple stacked lenses of disseminated Fe-Ni-Cu sulfide associated with the olivine adcumulate core. This core is interpreted as the pathway position that focused the flow of komatiite lava away from the vent. Rather than being linked by sheeted bodies of orthocumulate rocks, as is typically the case along strike to the north, the dunite lenses at Yakabindie appear to be capped by a strike-continuous sequence of thin komatiite flow units. There is no evidence of the fractionated sequences of pyroxenite and dolerite, which occur in pathway positions within the Mount Keith ultramafic unit to the north and which reflect late-stage ponding and in situ fractionation of komatiite lava. Three sets of synvolcanic structures are recognized in the broader Agnew-Wiluna belt and a model of oblique extension at ca 2.7 Ga is proposed. A NNW-trending set of structures marks the overall rift orientation at ca 2.7 Ga but is probably inherited from an earlier ca 2.81 Ga phase of rifting. A NW-trending set is thought to represent ca 2.7 Ga transfer faults, but may also have much older roots. These structures produce marked sinistral offsets in both the greenstone stratigraphy and the gravity response and can be used to divide the Agnew-Wiluna belt into rift segments. The third set of early structures trends NNE, subparallel with the volcanic grain of the greenstones as inferred from the orientation of komatiite lava pathways. These are thought to have originated as extension-orthogonal normal faults at ca 2.7 Ga. At the regional scale there is a strong spatial association between the larger Fe-Ni-Cu sulfide deposits of the Agnew-Wiluna belt and the locus of postulated NW-trending transfer zones, whereas at the deposit scale, intersecting NW- and NNE-trending synvolcanic faults exert a control on the location and best development (in terms of thickness and/or grade) of Fe-Ni-Cu sulfide mineralization in some deposits. These spatial associations have major implications for exploration targeting at both regional and deposit scale. © 2016 Society of Economic Geologists, Inc.

BHP Billiton | Date: 2013-02-13

A process for the production of a high grade nickel product including the steps of: a) providing at least one heap of a nickeliferous lateritic ore and leaching that heap with a suitable lixiviant, preferably sulfuric acid solution, to produce a nickel rich pregnant leach solution (PLS); b) subjecting the PLS to an impurity removal step to precipitate ferric iron, and preferably partially precipitate aluminium and chromium as hydroxides; and c) recovering a high grade nickel product from the PLS preferably by either nickel ion exchange, solvent extraction, electrowinning, conventional multi-stage neutralization, pyrohydrolysis or sulfidation.

BHP Billiton | Date: 2013-09-13

A process for extracting uranium from an acidic uranium, chloride, iron and sulphate containing solution, including the steps: a. contacting the solution with an organic phase containing a trialkylphosphine oxide to form a uranium loaded organic phase; b. scrubbing the uranium loaded organic phase to remove any impurities and form a scrubbed organic phase; c. stripping the scrubbed organic phase with an acidic sulphate solution to produce an aqueous uranium strip solution; and precipitating a uranium product from the aqueous uranium strip solution.

Discover hidden collaborations