Photograph showing part of a jack train hauling lumber and other supplies in Clear Creek County. These jack trains or pack trains played an important role in the mining operations especially prior to the arrival of the railroads. They were used to haul wood, machinery, supplies, food and water to the mines, and ore from the mines to the mills. Both horses and burros were used for packing, but burros could carry more weight, work longer hours on less feed, and are were more sure-footed on narrow rocky trails. Each burro was capable of carrying at least 200 pounds. Depending on the terrain the ...