<p>Near Prague,Czech Republic is old lime mine. Most of it is closed but one short transport tunnel under one hill is publicly accessible. Tunnel has profile around 2,5x2,5m and it's slightly bended and it's about 100m long. I estimate that hill above it is about 50m high from floor of tunnel. Aproximate location: 50°02'28.0&quot;N 14°22'32.1&quot;E</p>
<p>In middle of tunnel this immediately caught my attention, as it was reflecting light from my headlamp a lot. Its like some very wet yellow coating on rock side of tunnel.</p>
<p>Area on photo is 2m wide and 1-1,5m high. Tunnel was completely dark, and only source of light was headlamp and flash in my camera so the photo is quite dark</p>
<p>According to geological map of area the base rock is Lime and Hornblende from lower devon,emsian</p>
<p>What is this coating? I found this site post-trip, so I tried to answer all question in quide as best I can and I can go into that tunnel again and provide all needed information</p>
<p><a href="https://i.sstatic.net/D2MbE.jpg" rel="noreferrer"><img src="https://i.sstatic.net/D2MbE.jpg" alt="Strange coating in old lime mine shaft" /></a></p>

CC BY-SA 3.0
2016-08-10T08:10:00.223Z
@AlwaysConfused the blue/black portions is rock without coating
Rfilip
<rocks><mineralogy><minerals><mining>
Strange coating in old lime mine shaft
Rfilip
# Strange coating in old lime mine shaft

(Asked by: username_0 on 2016-04-05)

Near Prague,Czech Republic is old lime mine. Most of it is closed but one short transport tunnel under one hill is publicly accessible. Tunnel has profile around 2,5x2,5m and it's slightly bended and it's about 100m long. I estimate that hill above it is about 50m high from floor of tunnel. Aproximate location: 50°02'28.0"N 14°22'32.1"E

In middle of tunnel this immediately caught my attention, as it was reflecting light from my headlamp a lot. Its like some very wet yellow coating on rock side of tunnel.

Area on photo is 2m wide and 1-1,5m high. Tunnel was completely dark, and only source of light was headlamp and flash in my camera so the photo is quite dark

According to geological map of area the base rock is Lime and Hornblende from lower devon,emsian

What is this coating? I found this site post-trip, so I tried to answer all question in quide as best I can and I can go into that tunnel again and provide all needed information

[![Strange coating in old lime mine shaft](https://i.sstatic.net/D2MbE.jpg)](https://i.sstatic.net/D2MbE.jpg)

**Tags:** rocks, mineralogy, minerals, mining

> **Comments:**
> **username_0**: @AlwaysConfused the blue/black portions is rock without coating  

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## 0 answers

