Take twin boom Jumbo advancement for example, most drills these days are using a 5m steel to drill the holes, that are then charged and fired with explosives. You never get the whole 5m in advancement, how much you get depends on where you placed the holes and most importantly, how straight those holes are. A good jumbo operator can get up to 4.6m advancement while others may only get 4.1m. The difference can be measured, with the average cost of a metre advancement between $5000 and $7000 a metre. If you have one operator getting half a metre more per cut (the term used to describe each advancement) and with each operator normally expected to get at least 2 cuts per shift. Over time the difference can be massive and measured in the hundreds of thousands of dollars over the year. Little wonder that people in these jobs often get paid $1500 a day plus. Keep in mind that their bonus is paid in metres advanced, instead of time spent on the job.