For a six-year period in the 1880s some 9,000 tonnes of borax ore were dragged out of 
A 20-mule team consisted of 18 mules and a pair of horses - one of which was ridden by the Teamster (or Muleskinner). According to the
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That's ten tonnes from 190 feet below sea level to an elevation of 2,000 feet in temperatures in excess of 130 degrees. That's exhausting work, and it would be a good few years until trucks were able to do this.
And in complete contrast, this is how it's done today. I photographed this heavy haulage operation in the 