title: Investigating concentration distributions of arsenic, gold and antimony in grain-size fractions of gold ore using instrumental neutron activation analysis.
abstract: Instrumental neutron activation analysis (INAA) has been used to quantify concentrations of arsenic (As), gold (Au) and antimony (Sb) in grain-size fractions of a gold ore. The ore, which was taken from the Ahafo project site of Newmont Ghana Gold Ltd., was fractionated into 14 grain-size fractions using state-of-the-art analytical sieve machine. The minimum sieve mesh size used was 36mum and grains >2000mum were not considered for analysis. Result of the sieving was analysed with easysieve(R) software. The<36mum subfraction was found to be the optimum, hosting bulk of all three elements. Arsenic was found to be highly concentrated in<36-100mum size fractions and erratically distributed in from 150mum fraction and above. For gold, with the exception of the subfraction <36mum which had exceptionally high concentration, the element was found to be approximately equally distributed in all the size fractions but slightly "played out" in 150-400mum size fractions. Antimony occurrence in the sample was relatively high in <36mum size fraction followed by 600, 800, 400 and 36mum size fractions in that order. Gold content in the sample was comparatively far greater than arsenic and antimony; this is indicative of level of gold mineralization in the concession where the sample ore was taken. The concentration of gold in the composite sample was in the range 564-8420ppm as compared to 14.33-186.92ppm for arsenic and 1.09-9.48ppm for antimony. Elemental concentrations were correlated with each other and with grain-size fractions and the relationships between these descriptive parameters were established.
authors.affiliation: National Radioactive Waste Management Centre, National Nuclear Research Institute, Ghana Atomic Energy Commission, P.O. Box LG 80, Legon-Accra, Ghana. mawuutorli@yahoo.com
authors.forename: M
authors.initials: M
authors.lastname: Nyarku
authors.forename: B J B
authors.initials: BJ
authors.lastname: Nyarko
authors.forename: Y
authors.initials: Y
authors.lastname: Serfor-Armah
authors.forename: S
authors.initials: S
authors.lastname: Osae
mesh_terms: D000965:Antimony / Q000032:analysis* / Q000737:chemistry; D001151:Arsenic / Q000032:analysis* / Q000737:chemistry; D006046:Gold / Q000032:analysis* / Q000737:chemistry*; D008906:Mining / Q000379:methods*; D009501:Neutron Activation Analysis / Q000379:methods*; D010316:Particle Size
chemical_list: D006046:Gold; D000965:Antimony; D001151:Arsenic