Nick Morrison reports on his visit to the salt mine in Loule Portugal
The Portuguese salt mine at Loule in Portugal was discovered by accident .
The area then was highly agricultural – much of it still is.
Freshwater is quite scarce in many parts of Portugal . They were drilling for water in the 60s and what came up was saltwater , more boreholes were sunk with exactly the same result .
The salt mine was opened in 1964 using traditional mining methods including explosives.
Initially 200 personnel were employed . Fortunately these mainly came from another mine that was closing down . Explosives were phased out which meant fewer personnel , these were achieved through natural wastage .
Mining has been carried out in Portugal since at least the Roman times . Some copper mines still exist in Portugal . Mining is reckoned to be a hazardous occupation . The HSE describe it as the most hazardous with construction coming second . Recognising this the mine employees can retire one year early for every two years of employment . There are two employees of this mine that have served for 43 years .
It is also the only mine in Portugal where you do not need to use a face mask . Salt mines curiously are very healthy places especially if you have lung conditions . So much so the Russians and the Polish have opened salt clinics to treat lung conditions .
The mine uses the pillar and cavern technique common to coal mining . Here it departs from conventional coal mining technique as there are no pit props in sight. I have been down a conventional coalmine and the salt mine was way different .
It was explained to us that the salt under the conditions of pressure and tectonic movement is almost like a plastic and it results in these marked curved strata .
Instead of quite narrow and shallow tunnels of a coal mine we saw curved tunnels in some cases 40 foot or more high. Indeed they are so cavernous that some concerts and the like are held down there .