Today, RIO broke below trendline support, but here's an interesting observation. The first chart is drawn on an arithmetic scale, the second on a semi-log scale. On the arithmetic scale, the trendline support was only broken today. But on the semi-log scale it broke the support a month ago and since then the rally has failed to break back above the trendline.
Arithmetic scale.
Click to enlarge.
Semi-log scale.
Click to enlarge