Were there sell-offs to Western or Eastern interests? Did they re-nationalize privatized resources or always keep them 'in house'? Was the demand for resources just not there yet to garner foreign interest?
After the dissolution of the USSR and the collapse of the command economy, Russia found itself in a dire financial situation. They needed a mass privatisation, but they did not want for their national resources to fall in the foreign, mainly American hands.
The solution was to offer their mines and other national recourses to Russian citizens and that was how oligarchs emerged. A handful of people were able to buy Russian national recourses cheap and subsequently make huge profits as a result of it.