This note was posted to the Titanium Bolting FB Group 14 January 2020
The large cave at the Pra Nang side of Klao Luk Choee is home to the classic Todd Skinner route Best Route in Minnesota. At the base of that route there is a white powdery material in great abundance. Analysis shows it to be a sulphate, almost certainly reasonably pure calcium sulphate.
Quite how significant the dissolution by sulphuric acid has been in the speleogenesis of this impressive cave is hard to judge, but as far as climbers are concerned, what matters is that this is going to be a tough environment for low grade stainless steel anchors.
A note to Doubting Thomas – how do I know it is calcium sulphate?
- no effervescence, but poorly soluble in 1M HCl
- the amount of BaSO4 precipitated roughly matches sample size. See photo below for two sample sizes in duplicate.
- is there perhaps some magnesium present as well as calcium? – possibly. The Lopburi series has dolomitic sections interspersed through it. But MgSO4 is freely water soluble, and this is not exactly a dry cave.