The Samti Gold Deposit

(From The Geology and Mineral Resources of Afghanistan, United Nations, ESCAP, 1995)

The most important gold placer in Afghanistan is the Samti deposit in the Takhar province west of Badakshan. The Samti deposit (37°34’36”N 49°49’–69°54’E) represents an alluvial placer of 8 km long and 900–1700 m wide and has an average of 27.9 m groove sample depth. The placer comprises 2 beds: the lower bed of 25–45 m thickness consists of pebble-boulder material; the upper bed is 5–20m thick and is made of sandy loam material. The gold concentrations are thought to be derived from a combination of primary sources and the remobilisation of palaeo-conglomerates. The characteristic feature of this placer deposit is its spotty pay streak, both in plan and section with the highest gold content being in the placer's middle segment. The gold-bearing formations rest both on bedrock and on adjacent eluvial formations. Gold concentration in the 0.25–4.00 m thick bed ranges from 100 mg/m³ to 30–40 g/m³. Lithologically, the gold-bearing formations are identical with the overlying barren deposits; their upper boundary can only be defined by sampling.

Within the placer, there are 3 zones of possible commercial interest

• The Right Placer is 5 km long and 90–490 m wide, has an average of 30.8 m groove sample depth, with an average content of 493 mg/m³ gold across the whole section.
• The Central Placer is 4.8 km long and 80–450 m wide and contains two pay-streaks, both having a comparatively regular gold distribution, with an average content of 228 mg/m³ gold throughout the whole section.
• Slope-Side Placer is on the left slope of the valley and has two pay-streaks referred to as the right and left pay-streak. The right pay-streak is 1.8 km long and 80–160 m wide, with an average content of 258 mg/m³ gold. The left pay-streak is 1.48 km long and 80–280 m wide and has an average content of 258 mg/m³ gold.

The Samti Placer carries yellow, dark and light yellow gold particles with well rounded grains predominantly in size with a fineness of 955.2. The Samty deposit may contain between 20 tonnes to 25 tonnes of gold of a high fineness but the extent of the overburden (20 m) may seriously limit its economic potential.