Some 150 years ago, high on a Colorado mountain whose name has been lost to time, a pair of miners struck gold at exactly the same spot. Neither wished to lose out on his newfound wealth, so both pointed their asses—by which I mean donkeys—toward the claims office in the nearest town. Thus ensued a race so heroic, it soon became the stuff of legends. Or maybe myth. Anyway, this is the epic contest many credit with launching a thousand burros—or at least the 58 competing in Idaho Springs’ Tommyknockers Mining Days burro race this past summer, including my partner, Marsha. “She’s ornery,” Marsha’s owner, Jennifer Biltoft, cautioned me. “She’s dragged me down this course before.”

As a relative rookie to the burro-racing scene, I had to team up with an unfamiliar rental donkey for the annual race. But two-time world champ George Zack—like other experienced burro racers—arrived at the starting line with a long-term partner, Jack. And yes, it’s “partner,” not “ride.” You run alongside your donkey during the race, which is a nod to the competition’s legacy: The miners couldn’t ride their donkeys to the claims office because the burros were lugging essential mining gear, so neither can you. Also, each donkey carries a 33-pound load containing a pick, gold pan, and shovel—although animals shorter than 40 inches at the shoulder have no minimum load.

The 5.5-mile Idaho Springs race is the shortest of six stops on the Western Pack Burro Ass-ociation’s circuit. (The group’s motto? “Celebrating 67 Years of Hauling Ass.”) But with the 29-mile world championship in Fairplay looming a week later, burro racing’s best runners had traveled to Clear Creek County to prepare. As Marsha and I walked to the starting line, I let the spirit of the competition wash over me. “Nice ass,” I told my fellow competitors (including Justin Mock, the top U.S. finisher at the 2010 London Marathon).

After a parade through town, the race began and our herd took off, hee-hawing into the hills. They might appear lazy and slow, but burros can hit 40 mph. Marsha never touched top speed; still, she was fast enough to serve as my tow truck, pulling me 800 feet to the high point of the course. We passed a few teams on the rocky descent toward the Argo Gold Mine and Mill. Back in town, on our way to the finish line at the Elks Lodge, we had another duo in sight—a triathlete and a burro named Scratch. I figured we were home free when Scratch detoured down an alley. Suddenly, though, Marsha stopped and, despite my tugging and pleading, refused to move until Scratch returned to the course.

Thanks to Marsha’s bout of obstinacy, we settled for 12th with a time of 50:51. Mock won the $450 top prize, but the following week, Zack and Jack exacted revenge by taking their third world title. The pair then went on to capture the coveted Triple Crown of burro racing by winning the WPBA’s Buena Vista and Leadville races, too. All together, Zack and Jack won more than $1,450 in prize money, or (if we want to get historical about it) just over an ounce of gold.

If you go…

Date: July 17
Time: Noon (burro weigh-in at 10:30 a.m.)
Cost to race: $35 to participate (free to watch)
Need a partner?: Rent a burro for $75 through the Laughing Valley Ranch.