Tronaunderground mining techniques – bore hole, block caving …
The Trona near Green river, Wyoming is the chief known deposit in the earth and lies in encrusted evaporate leaves from 800 to 1600 feet below ground, where the Trona was placed in a lake during the period of paleogene. Trona has also been excavated at Lake Magadi in the famous rift valley in Kenya for virtually 100 years, and emerges in 'salt ...