Shale oil extraction Energy estimates that the "ex-situ" processing would be economic at sustained average world oil prices above $54 per barrel and "in-situ" processing would be economic at prices above $35 per barrel. These estimates assume a return rate of 15%. Royal Dutch Shell announced in 2006 that its Shell ICP technology would realize a profit when crude oil prices are higher than $30 per barrel ($190/m), while some technologies at full-scale production assert profitability at oil prices even lower than $20 per barrel ($130/m). To increase the efficiency of oil shale retorting and by this the viability of the shale oil
Barrel racing course after time begins. Contestants cannot be required to start a run from an off-center alleyway, but contestants are not allowed to enter the arena and "set" the horse. It is required that the arena be "worked" after twelve contestants have run and before slack. Barrels are required to be fifty-five gallons, metal, enclosed at both ends, and of at least two colors. Competitors in the National Barrel Racing Association (NBRA) are required to wear a western long-sleeved shirt (tucked in), western cut pants or jeans, western hat, and boots. Competitors are required to abide by this dress code beginning