Geology and mineralisation of the Mewet Vein, Jelai Gold Project ...

PT GMT Indonesia
Mewet Vein : Jelai Gold Project
10
10.1
SAMPLE PREPARATION, ANALYSES AND SECURITY
Sampling and Analysis
10.1.1
Ivanhoe Mines Sampling and Analysis
During the Ivanhoe programme, all core handling and sampling was conducted by geologists
employed by that company.
The Ivanhoe sampling and analysis programme followed the following methodology:
• Core was geotechnically and geologically logged, photographed, cut and sampled at a
central core processing facility, near to the Mewet village.
• Original core photographs were catalogued and stored at the P.T. Indonesia Exploration
Sejati office in Tarakan. the core from the programme was originally stored in a
warehouse facility in Tarakan but has now been discarded by the locals, who sold the
core trays for scrap metal.
• Geologically interesting and mineralised core was sampled as half core with a minimum
sample interval of 10 centimetres and a maximum interval of 1 metre. Samples through
geologically monotonous rock were quarter cut and sampled on a 2 metre basis.
• Samples were assayed for gold by fire assay (50g charge, DL 0.01 ppm Au) and silver
by AAS (aqua regia digest, DL 1 ppm Ag) at PT Indoassay, Balikpapan. In the early drill
holes, a number of holes were also analysed by Cu, Pb and Zn by AAS and As by
hydride-AAS.
• Limited samples were re-submitted to PT Indoassay and PT Inchcape Utama in Jakarta
for check assaying. According to records, no significant discrepancies were found in
sample repeats and re-assaying.
• The repeatability of Au assays was reported as excellent with correlation coefficients
varying from 0.9786 for values of 0.00-1.00 ppm Au and 0.9983 for values of >5.00 ppm
Au.
No routine blank or standard samples were submitted during the original Ivanhoe programme
but the laboratory produced a number of QA/QC reports on the sampling and analysis
programme, including the internal round robin analyses conducted by the laboratory itself and
no major discrepancies have been outlined in reports written at the time. However, the actual
QA/QC reports are not available for review.
Correlation of the Ivanhoe primary analyses and repeats are shown in Figure 7.
10.1.2
Jelai Cahaya Mineral Sampling and Analysis
During the drilling conducted by JCM, the routine was very similar to the Ivanhoe procedures
and this has allowed a good correlation in the quality of the data between the two companies.
The procedures outlined by JCM for core administration is as follows:
• The core trays are marked in the field and the core placed in the trays, the driller
measures the core run, recovered length and calculates the recovery at the rig site for
tracking performance,
• The trays are transported to the core shed at the main base camp and the geologists
check the core recoveries, log RQD and lithology and determine the sections for
analysis,
• The core is marked up by the geologist and the sample markers placed at intervals, the
core is split by a diamond saw and the runs sampled according to the sampling sheet
prepared,
0065 JCM/GEO/2009.04 Page 30