ABSTRACT
Commercial and scientific activities at high altitude have greatly increased over the last few years. Several mines are now situated at altitudes of 4000-6000 m. Some mines, for example Collahuasi in north Chile use a commuting pattern for the workers. They live at sea level but are transported by bus up to the mine where they spend 7 days and they then return to their families at sea level for a further 7 days. The cycle is then repeated. In this mine, the ore is at about 4400 to 4600 m, but the camp where the miners sleep is at a lower area of 3800 m. In a new mine under development at Toromocho, Peru, the ore deposits are at 4700-4900 m and the camp is at about 4500 m. One plan is to offer oxygen enrichment for the workers during the night using nasal cannulas. Several telescopes have been installed at an altitude of 5000 m at Chajnantor in north Chile, including the enormous multinational radiotelescope, ALMA. Although many of the astronomers work at a lower altitude, it is necessary to have some people on the site and the rooms are oxygen-enriched to maintain an oxygen concentration of about 27%. Portable oxygen is used to service the telescope antennas
in the field. A recent development is the Chinese railway between Golmud, Qinghai Province and Lhasa, Tibet. The train reaches an altitude of over 5000 m and all the passenger cars have oxygen generators that raise the oxygen concentration in the air. Construction of the railway involved as many as 100 000 people and there were numerous cases of high altitude diseases. Military operations have been conducted at altitudes up to 7000 m in the dispute between India and Pakistan with some soldiers moving rapidly to high altitudes and down again. Oxygen enrichment of room air at very high altitude improves neuropsychological function during the day and enhances sleep at night. This technique is also potentially valuable at much lower altitudes, such as ski resorts, where sleep is a problem.
