I don't have specific numbers, but one engineer friend once compared the fragments of a failed turbine disc (of a RB211 or CF6 for example), as having the mass and velocity of a cannon ball. Good Luck in trying to protect the plane from such damage.
And every engine manufacturer has had more than a few such failures over the decades. There are several possible causes, which the metallurgical people are adept at sorting out.
First - most obvious - is overspeed. In that case, the reason for the overspeed must be nailed down, and/or an overlay control system installed to provide redundancy. Think of a helicopter engine encountering a geartrain failure in the helo transmission. Without such loss-of-load protection, the gear failure induces a overspeed in the engine.
Second - overtemperature operation can degrade the material properties to the point that the disc (or shaft) cannot sustain normal operating loads. (This is what happened in the collapse of the WTC towers on 9/11).
Third - a material defect in the disc may not be detected for a few hundred or many thousands of start/stop cycles - until it finally lets go. This is called Low Cycle Fatigue or LCF. A huge amount of quality inspection and process control goes into disc manufacturing, and the state of the art improves year-by-year. Even so, the predicted safe life (in cycles) becomes part of the certification standards; once a highly-stressed prime-reliable part reaches its LCF limit, it must be scrapped and replaced.
Hope this helps.