This chart, above, shows that the decline in CMG did not appear out of nowhere. Prices held above $700, but the On-Balance-Volume (OBV) line showed some selling. Prices weakened below the 50-day Moving Average (MA) and gapped down below $700. Prices also broke below the 200-day MA. CMG could continue to weaken, and could eventually retest the June lows and support around $600.
In this chart, above, we do not see the gap that exists on the daily chart. We can see that CMG broke below the 40-week MA and that the OBV line peaks in mid-2014. The Moving Average Convergence Divergence oscillator also peaks in 2014. The $600 level, which is support in 2015, can be seen as resistance in early 2014.