Krueng Heureueng (also Kr. Heureueng, modern Krueng Heureueng) is a river of Atjeh at whose lead-zinc occurrence the highest-grade lead ore of the colonial Atjeh mineral record was assayed. The Krueng Heureueng locality is recorded in Van Bemmelen’s *Geology of Indonesia* (1949) in the Lead and Zinc in Sumatra chapter, with an assay of 76.1 % Pb, 2.2 % Zn, 0.5 % Fe, 0.15 % CaO, 1.1 % SiO₂, and 920.0 gr/t Ag — the highest silver content of any Atjeh lead-zinc occurrence recorded in the colonial geological literature.
The assay
Van Bemmelen’s Table for the Atjeh lead-zinc occurrences records the Krueng Heureueng assay as follows (1st sample, small):
| Component | Percentage |
|---|---|
| Pb | 76.1 % |
| Zn | 2.2 % |
| Fe | 0.5 % |
| CaO | 0.15 % |
| SiO₂ | 1.1 % |
| Ag | 920.0 gr/ton |
The 76.1 % Pb content is the highest lead grade recorded for any Atjeh lead-zinc locality, and the 920 gr/ton silver content is the highest silver grade. The combination makes the Krueng Heureueng occurrence, on paper, one of the most attractive lead-zinc-silver prospects in the colonial Atjeh mineral record. The small sample size (“1st sample, small”), however, indicates that the assay is based on a hand-sample rather than on a systematic channel-sample or drill-core, and the actual tonnage and average grade of the occurrence are accordingly unknown.
Place in the Atjeh lead-zinc record
The Krueng Heureueng locality is one of the two Atjeh lead-zinc occurrences recorded in the colonial geological literature, the other being Krueng Isep (with 65.13 % Pb, 8.30 % Zn, 680 gr/t Ag). The two localities together constitute the entire documented colonial-era lead-zinc record for Atjeh, and the contrast between them is instructive: the Krueng Heureueng assay has the higher Pb and Ag grades but the lower Zn grade, while the Krueng Isep assay has the lower Pb and Ag grades but the higher Zn grade. The contrast suggests a paragenetic zonation within the Atjeh lead-zinc province, with the Krueng Heureueng occurrence representing the higher-temperature, more silver-rich end of the zonation and the Krueng Isep occurrence representing the lower-temperature, more zinc-rich end.
Significance
Krueng Heureueng is significant for the encyclopedia of Acheh history because it is the site of the highest-grade lead ore of the colonial Atjeh mineral record — 76.1 % Pb with 920 gr/ton Ag — and accordingly one of the most attractive lead-zinc-silver prospects recorded in the colonial geological literature on Atjeh. The fact that the occurrence was never developed is, like the non-development of the Kr. Geuenteuet iron-ore deposit, evidence of the colonial state’s unwillingness or inability to translate geological occurrences into productive mines. The Krueng Heureueng assay is also the only quantitative record of a high-grade lead-silver occurrence on Atjeh territory, and it accordingly occupies a disproportionately important place in the printed record of Atjeh’s mineral geography.
See Also
Source
The Geology of Indonesia, by R. W. van Bemmelen, Vol. II: Economic Geology (The Hague: Government Printing Office; Martinus Nijhoff, 1949), p. 163 (Fig. 35 key, Atjeh lead-zinc occurrences, with assay table).