As can be seen in this chart (PRB vs. junior gold producers), the last few days have been painful as juniors are on the move and Probe is down
http://finance.yahoo.com/echarts?s=GDXJ+Interactive#symbol=gdxj;range=5d;compare=prb.v;indicator=volume;charttype=area;crosshair=on;ohlcvalues=0;logscale=off;source=;
But as a long term investor in PRB, I know that whether this is done deliberately by some traders or not, PRB always comes back and generally will not only make up the diffference but will usually perform better than others in this category. In other words a good time to buy!