There's no quicker way to get a geologist excited than to talk about a potential carbonatite. An article in "Global New Light of Myanmar" describes what could be one:
The article is a condensed version of some geological studies from a century ago. Most of the article details limestone sort of rock formations. In there is a quick description of an old silver mine.
Silver occurs in nature together with gold, copper, lead, zinc, and other metals. While there are real silver mines, most silver is mined as a by-product of other metals, particularly gold and copper. While it is heavy enough to be found in river placer deposits with gold, silver oxidizes so easily that it usually corrodes away before it can be found. The main exception to this is what the ancients mined as "electrum", a mixture of gold and silver.
Silver seldom can be found in a limestone environment, unless it is in a carbonatite. Some of the very best mines in the world mine carbonatite rock. Think of carbonatite as melted limestone. The limestone melts to marble and then calcite. The metals contained in the rock group into veins of metal, which are relatively easy to separate out because of the softness and easy dissolvability of the calcite. While carbonatites are relatively rare in nature, they've been extensively studied.
The old silver mine isn't necessarily in a carbonatite, but the possibility of it being so makes this a prime candidate to explore.