The Geudong Concession is the gold-dredging concession on the West coast of Atjeh, in the Meulaboh coastal basin, on which the M.A.E.M. began production in 1940 with two bucket dredges — the only colonial-era gold-dredging operation on Atjeh territory, and accordingly the only Atjeh locality for which colonial-era gold production figures are recorded. The Geudong Concession is recorded in Van Bemmelen’s *Geology of Indonesia* (1949) in the Production subsection of the Meulaboh-placers account.
The 1940–1941 dredging operation
Van Bemmelen’s record of the Geudong Concession operation reads:
“Production started in 1940 in the Geudong Concession with two bucket dredges (buckets of 6 cubic feet) with joint capacity of 270,000 cb yard per month. The deposit contained 55–60 per cent boulders, the largest of which could just be handled, and 40–45 per cent fine material. There were two types of gold: fine gold with somewhat higher silver content, which was easily amalgamated, and coarse gold with lower silver content, which was difficult to amalgamate. The platinum production was some kilograms per month. Treatment. Amalgamation, Wilfly-tables.”
The technical details — two bucket dredges with 6-cubic-foot buckets, a joint monthly capacity of 270,000 cubic yards, and a deposit of 55–60 % boulders and 40–45 % fine material — make the Geudong operation a substantial industrial enterprise by the standards of the colonial Atjeh mineral economy. The 55–60 % boulder content, in particular, indicates that the dredges were working a coarse-grained alluvial deposit that required robust equipment and careful management — and the fact that “the largest [boulders] could just be handled” suggests that the dredges were operating at the upper limit of their boulder-handling capacity.
The two types of gold
The Geudong operation distinguished two types of gold in the deposit:
- Fine gold with somewhat higher silver content — easily amalgamated (i.e. readily recovered by the mercury-amalgamation process).
- Coarse gold with lower silver content — difficult to amalgamate.
The distinction is metallurgically significant: the higher silver content of the fine gold makes it more readily amalgamated (because silver promotes the wetting of gold by mercury), while the lower silver content of the coarse gold makes it less amenable to amalgamation. The two-type gold population also suggests a dual source for the alluvial gold — perhaps a fine-grained distal source and a coarser proximal source, with the two populations mixing in the alluvial deposit.
The platinum byproduct
The Geudong operation also produced “some kilograms per month” of platinum as a byproduct of the gold-dredging. The platinum is geologically significant because it indicates that the pre-tertiary Old Slates Formation and granite contacts of the West-Atjeh interior — which supplied the alluvial gold to the Meulaboh basin — also contain platinum-group minerals. The platinum byproduct of the Geudong operation is the only recorded colonial-era platinum production on Atjeh territory.
The 1941 mercury observation
For the De Groot 1946 observation that the Geudong dredges were gaining mercury with each clean-up — indicating that the alluvial deposits themselves were supplying native mercury and cinnabar to the gold-tables — see the entries on Mercury in Atjeh and Basin of Meulaboh.
Significance
The Geudong Concession is significant for the encyclopedia of Acheh history because it is the site of the only colonial-era gold-dredging operation on Atjeh territory, and accordingly the only Atjeh locality for which colonial-era gold production figures are recorded. The operation’s two bucket dredges, with a joint monthly capacity of 270,000 cubic yards, represent a substantial industrial enterprise by the standards of the colonial Atjeh mineral economy, and the platinum byproduct of “some kilograms per month” is the only recorded colonial-era platinum production on Atjeh territory. The Geudong Concession accordingly marks the high-point of the colonial mineral economy of Atjeh — the moment at which the residency’s geological potential was, for the first and only time, translated into actual industrial production.
See Also
- Acheh
- Atjeh’s Westkust
- Basin of Meulaboh
- C. de Groot
- Gold and silver in Atjeh
- M.A.E.M.
- Meulaboh
- Mercury in Atjeh
- Platinum in Atjeh
- Van Bemmelen’s The Geology of Indonesia (1949)
- 1940
- 1941
- 1946
Source
The Geology of Indonesia, by R. W. van Bemmelen, Vol. II: Economic Geology (The Hague: Government Printing Office; Martinus Nijhoff, 1949), p. 121 (Basin of Meulaboh, Production subsection).