Volcán Acotango is a volcano at an elevation of 6.052m (19,856ft) above the sea level, located in Parque Nacional Sajama, in the border between Bolivia and Chile. There’s a 4x4 mine trail that climbs up at an elevation of 5.509m (18,074ft) above the sea level. The unrideable track continues a bit higher, but it’s not drivable. It's one of the highest mountain roads of the country.
It’s a real challenging road and a true test of your vehicle and your stamina because the road abounds in twists and turns with wheels sometimes hanging above the precipice. Located in Departamento de Oruro, Bolivia, the mine road to Volcán Acotango is accessed from the Chachacomani-Tambo Quemado road and is used by 4x4s up to 4.900m as the sulphur mine on the mountain is due to be reopened and work is being carried out to erect some buildings at this height. The road becomes steep above 4.800m but the surface is in ok condition to 5.250m, above which it deteriorates.
This trail is usually open on summer months, but it can be closed anytime because avalanches and heavy snowfalls can sometimes block some sections of the road. To climb the summit from the Chilean side is dangerous due to land mines, however it is relatively safe to climb the summit from the Bolivian side. The southern ascent starts over a glacier and passes an abandoned copper mine. Conditions can change quickly and be harsh. It’s one of the highest roads of South America.
More pics&info: http://www.whileoutriding.com/south-america/bolivia/burial-chambers-frozen-potatoes