“ These rocks conceal an ore which dyes glass blue and hardens steel ”
From here to the Coor ravine, lay the vestigial remains of approximately ten underground galleries which once comprised the now defunct Gollyre mine. Today collapsed, they were formerly part of a cobalt exploitation spreading as far as the large Grand Praz mine, beneath “Les Bourrimonts”. The average thickness of the vein was 50 cm, and the ore was mostly composed of gersdorffite and skutterudite in a dolomite gangue.
The name cobalt comes from the word "kobold" (goblin),
i.e. a mischievous creature and prankster living in the depths of the
earth, according to German folklore. Cobalt has been used as a pigment
since 2250 BC, to impart the colour blue to glazes and ceramics and was
called Nippur Blue. Later on - called smalt- it was used as a blue
pigment by Renaissance painters ( including Titian, Veronese, El Greco,
Rubens, Brueghel, and Rembrandt among others.) Metallic cobalt is a
hard, stainless, ferromagnetic element, with a melting point of 2723
degrees Fahrenheit. Because of its exceptional mechanical properties it
has a diverse range of uses from magnets to turbine blades for jet
engines. Cobalt is also widely used in the space industry and in highly
resistant superalloys for machinery. Moreover, one of its radioactive
isotope is used in medicine. Finally, being a crucial constituent in the
synthesis of vitamin B12 (cobalamine), cobalt is essential to good
health.
Mentioned in Anniviers as early as 1767, this rare metal was sporadically mined here until 1865. The exact production of the Gollyre mine is unknown, as the ore was mixed with that coming from Grand Praz. However it is known, for example, that these two mines combined extracted 164 tons from 1849 to 1858; totaling a net profit of 176'000 francs at the time, equivalent to over 12 millions today! And yet, how many times have we heard the expression: « The Valais is rich in poor mines »? For the record, the average salary of a miner in Valais was 2,80 francs a day in 1856…
Text : Stefan Ansermet, minéralogist