Title

The Carbonatite-hosted Apatite Deposit of Jacupiranga, Southeast Brazil - Styles of Mineralisation, Ore Characterisation and Association with Mineral Processing

Abstract

The carbonatite-hosted apatite deposit at the Cajati open pit mine in the Jacupiranga igneous-carbonatite complex is located in south-eastern Brazil. The major styles of apatite mineralisation include veins or veinlets, small pods or patches, disseminated apatite and locally massive aggregates. The metallurgical concentration of the apatite is accomplished by grinding the carbonatite, removal of magnetite with a magnetic drum, size classification with cyclones and flotation to suppress carbonates and collect apatite. To examine the character of the apatite grains and to apply those observations to apatite beneficiation, specimens of carbonatite were collected from recent exposures in the mine and from selected drill holes. This study utilised a variety of microscopy methods, including transmitted and reflected light, cathodoluminescence (CL) and scanning electron microscopy with wavelength-dispersive spectrometers for mineral compositions. It was found that LREE, Na and Sr are the main elements replacing Ca in the apatite, with relatively low oxide contents (<0.5 per cent, but up to about one per cent for Sr). LREE and Sr contents consistently increase in the latest intrusions (C4, C5 and SP24). Chemical and morphological modifications of apatite were recognised to be related to detrimental effects on flotation recovery. Three examples illustrate this relationship: 1. Apatite with reddish CL is fractured. Locally that apatite exhibits no CL due to CL quenching caused by iron entering the apatite structure. 2. Apatite from the xenolith-rich area exhibits abundant fine, platy silicates that appear to interfere with flotation and lower apatite recovery. 3. So called 'hard' apatite, which is more difficult to grind, occurs in an area in the mine that was affected by hydrothermal activity. That activity is evidenced by the development of a bright, white CL rim in the apatite, and by the presence of late veins of carbonates and sulfides that fill fractures and appear to contribute to higher cohesiveness of those apatite grains.

Meeting Name

9th International Congress for Applied Mineralogy (2008: Sep. 8-10, Brisbane, Australia)

Department(s)

Geosciences and Geological and Petroleum Engineering

Keywords and Phrases

Apatite; Calcium; Carbonates; Chemical Modification; Concentration (process); Crystallography; Flotation; Iron Ores; Lithology; Magnetite; Mineralogy; Minerals; Mines; Mining; Open Pit Mining; Ores; Oxide Minerals; Quenching; Scanning Electron Microscopy; Silica; Silicate Minerals; Silicates; Sodium; Storms; Strontium; Apatite Deposits; Apatite Structures; Carbonatite; Characterisation; Detrimental Effects; Dispersive Spectrometers; Drill Holes; Flotation Recoveries; Hydrothermal Activities; Magnetic Drums; Mineral Compositions; Mineral Processing; Mineralisation; Morphological Modifications; Open-pit Mines; Oxide Contents; Size Classifications; Phosphate Minerals

Geographic Coverage

Brazil

International Standard Book Number (ISBN)

9781920806873

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2008 Australasian Institute of Mining and Metallurgy, All rights reserved.

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