Mineral Characterization

Petrographic Description
the petrographic study in fragments of mineralized rocks, showed a constitution essentially quartz – cathaclastic, of ash-coloured colorization, showing spaces and/or enriched sales with sulphurs, in general associated with a mineral of ferrous aspect and with a greenish-yellowish color.

In the quartz mass, we can see small opaque grains which are disseminated.

The material of greenish aspect showed in the microscope characteristics of aglomerates formed by micrograms and/or major crystals under prismatic forms, with no color or with coloring of greenish- yellowish tones.

With these observations in the microscope, plus the result of defraction of x-rays and the studies performed by electronic microscopes, with the help of the system of energy dispersive of x-rays, this material was identified as being of the series ESCORODITA (FeAsO4.2H2O) – MANSFIEL – DITA (A1AsO4.2H2O), being of low tenor in alluminum, therefore more approximate to the escorodite. Besides strange grains of biotyte were observed.

X-Ray Defraction
The main minerals detected by the x-ray defraction are presented below:

• quartz;
• Arseno-pyrrite;
• Pyrrite;
• Escorodite.

Determination of Sulphur Liberation Levels
The level of liberation of the sulphurs was calculated through observations in binocular magnifying glass and polarizing microscope.

Magnetic Separation
In preliminary tests with the magnetic separator FRANTZ, it was veryfied that the escorodite possesses a magnetic sensibility approximately of 15,000 gauss.

In this form were grinded the two kilograms of average samples of the mineral which were grinded (under 65 nets), obtaining 8 aliquots for the practices of magnetic separations to the humid in RAPID separator, presenting the distribution below:

• Fraction: Magnetic Concentrate Weight (%): 3.5
• Fraction: Magnetic Mix Weight (%): 4.6
• Fraction: Non-Magnetic Weight (%): 91.9

The magnetic concentrate, constituted essentially by the escorodite, with rare grains of non-liberated sulphurs, was chemically analysed by humid way, presenting a tenor of 16 ppm of gold.

With all, having the occurrence of escorodite represented in the mineral for barely 3.5% in weight, its maximum approximate contribution in terms of gold would be of 10%.

Mineralogical Composition
By studies of microscopes, the mineral sent to the laboratory presented the following mineralogical composition:

• - Quartz                                67,0%
• - Arseno-pyrrite                         15,0%
• - Pyrrite                                14,0%
• - Escorodite                              3,5%
• - Others (hematite + magnetite + calcopyrite)   0,5%
•                                        100,0%