Late start today so it was quite hot for the return trip. Rode past a rail spur that was under construction the last 3 years for a new potash mine. It passes through valley so they dug a massive sloped trough starting about 4 km back from the valley edge, built a tunnel, then buried the tunnel so the road could go back on top of it. The edge of valley is so sandy it looks like they had to haul in soil to line the slopes so they can plant grass.
The road at about 9:45 in this video is where the tunnel is:
https://vimeo.com/147614204 