Acotango and flat sandy area just before old mine settlement (not seen, a little bit higher on the left)
To go to BC just before Tembo Quemado turn left (from Bolivia) to Oruro, before pueblo of Chachacomani, find apoor track to your right when driving downhill.
Go up among bushes then cross the hopefully dry river and aim towards Acotango on the flat sandy area.
At the end of it go up left to old mine settlement BC 4900 m