Speeds depend on a number of factors including the gauge of the copper plant, bridge taps, aircore vs jelly, etc. The number of pairs and type of binder they are in also makes a difference.
Speeds over 20 Mbps are easily possible at 6000 - 9000 feet if using ADSL2+ annex for unidirectional traffic. One pair can be run in each direction to achieve synchronous speeds fairly easily and routing protocols can be used to take advantage of the two unidirectional pipes.
Speeds of 10 Mbps synchronous are possible with EFM at that distance on the right copper and pair bonding gives you the ability to link ag several pairs together at Layer 1 for pipes from 30 - 60 Mbps.
The published xDSL footage distances / speeds are frequently exceeded in real world telco operations.
In short...it all depends