Sulphur mines used to operate on upper western and southern flanks and were serviced by a road which reached 5650 m elevation. It is one of the highest (if not the highest) roads in the world. It has been used to descend on mountain bikes.
The Ollague Volcano suffered flank collapse during the Pleistocene and produced a large debris-avalanche deposit which extends westward and separates the Salar de San Martin from the Salar de Ollague salt flats.
3 youthful-looking silicic lava flows were employed after the collapse, but are probably still older than the last glaciations about 11,000 years ago.
A youthful-looking scoria cone on the lower WSW flank, La Porunita, was long believed to be relatively young, but has been dated to an age of 420,000 to 680,000 years.
From Ollague it is possible to observe campaments from ex sulphur workers. The campaments of Santa Cecilia and Santa Rosa can be visit and are placed on the feet of the Volcano.
Hedionda Lagoon there is a window from where it's possible to observe the Ollague volcano and stones with weave shapes.