History
Prior Ownership and Ownership Changes
The region has been actively explored and mined since the late 1800's but very little detail has survived.
The BRGM worked parts of the area during the 1970's and 1980's and have claims covering old working around
Betsiaka and Andavakoera. Small-scale informal mining groups and local entrepreneurs hold titles or
leases on lands covering some past producers and local villagers work high-grade veins.
Exploration and/or Development
Gold extraction from the Betsiaka-Andavakoera district was initiated in 1906. Between 1906 and 1909,
small-scale informal mining of surface material yielded 2829 kg of gold with 1223 kg produced in 1909.
From 1909 to 1922, several underground operations worked high-grade quartz veins to a depth of 60m by
driving 17 km of drift and a number of shafts. By 1922, total production amounted to 4142 kg of gold
and underground operations were becoming sub-economic. From 1923 to 1941, extensive, mainly informal
mining of alluvial or lag material had estimated production of 380 kg. Total declared production from
1906 to 1941 amounts to nearly 7,350 kg of gold with less than a quarter extracted from underground.
Since 1941, small- scale mining by local inhabitants has continued with unknown production.
Most gold production in the region was from BRGM's Betsiaka claim group that is surrounded on
three sides by PAMM Claims.
Detailed maps of the extensive workings found in the Andavakoera region are not available, and
available geological documentation requires compilation. The BRGM conducted work programs consisting
mainly of surface sampling and shallow diamond drilling near old workings.
Quartz-barite vein mineralization extends to the southwest at least as far as Ankitokazo where
Besairie described auriferous galena mineralization. Basantirie mentions deposits at Anjavy and other
locations on PAMM claims to the southwest of Ambilobe that suggest the entire southwest sector was worked
for gold.
Northeast of Andavakoera the productive vein systems are covered by unmineralized Triassic
sandstones. Stream prospecting completed by the BRGM in 1968, on lands presently held by PAMM, and
produced a number of unexplained pan concentrates containing cinnabar, gold, scheelite and tourmaline.
|
