27 August, 2009 - The department of geology and mines (DGM) has come across a rock sample with traces of gold in it in an area between Phuentsholing and Pasakha.
The department has around a hundred more samples and will be conducting further tests to find out the economic potential or viability of the deposit.
This is part of the DGM’s search for potential gold mines in Bhutan, which has received a big boost with this finding and, though no big deposits are confirmed, some promising clues have been found.
“The particular rock sample was tested in a laboratory of the United States geological services (USGS) and they have found 0.134 parts per million trace of gold, which is above average,” said the chief geologist and acting director of DGM, Ugyen Wangda.
In fact, the letter from American geologist Klaus J Schulz in 2008 says, “ 0.134 ppm gold is at the high end of the range found…and may warrant further examination of the sample area.” He also says that such iron-rich rocks can be a good host for gold lode deposits.
A Netherlands professor and minerals exploration expert, Westhoff, after visiting and studying the rock formation in southern Bhutan, had said in 2006 to DGM that there was a good potential for the presence of gold there.
DGM has also received information on the likelihood of gold being found in the region from a foreign mining expert. Simon, a United Nations educational, scientific and cultural organisation (UNESCO) staff and former USGS geologist, had recommended to DGM to send the rock samples to the USGS lab.
Though not made public, the first ever clues provided to DGM on the likelihood of gold was by Jang Pangi of the geological survey of India (GSI) that was exploring mineral content in Bhutan until the early 1990s. “He said that traces of gold could be seen in the Siwalik rock formation and its source must be the older Buxa rock formation above it,” said Ugyen Wangda. “Commonly the chances of gold and minerals being found is in the Buxa rock formation, which is around 10-15 km in thickness, and runs for around 200 km from west to east in the south.”
However, the key point will be finding gold in economically viable amounts or which can be extracted in an economically viable manner. Normally, the gold value in most rocks is 0.02 and anything above it is sign of gold, but one has to find gold deposits above 4.0 ppm to be economically viable.
The gold ore or rocks are normally crushed to powder and then melted at high temperature. Since gold is a heavy metal, it settles at the bottom.
DGM for now is pinning its hopes on the Phuentsholing- Pasakha area and also other areas near Gurung Khola in Sarpang and the Black Mountain area in Trongsa.
“We’ll look at these areas first, as they are potential sites, but there’ll also be other areas we will follow up later on,” he said. The chief geologist said that the key would be to finding the source or ‘provence’ of gold along the Buxa rock formation stretch.
DGM currently has a budget of Nu 800,000 for exploration of heavy metals like gold, but expects more resources with the mineral development policy, which is in the final stages of being sent to the cabinet for approval. “The policy will encourage the exploring of such resources in more detail,” said the chief geologist.
He said that, though GSI had in the past done some surveys, it covered only 33 percent of Bhutan, which was accessible.
DGM, however, faces a challenge with the lack of adequate equipment and trained manpower. The machine used to test for gold, the atomic absorption spectrometer, was defective for the last few years and only recently was a new one purchased to carry out tests.
By Tenzing Lamsang