The O.K. Corral is coming to Grass Valley to present its equine-assisted certification seminar to the public from 8 a.m. to 5 p.m., January 18 through 20. The seminar will be hosted by Purpose Ranch, a nonprofit, horse rescue organization. For more than 15 years, Greg Kersten, president of the O.K. Corral Series, has been certifying therapists and regular, everyday people to use horses in the fields of mental health and wellness. The seminar encourages attendees to look beyond horsemanship, irrational fears and their own biases by promoting the use of astute observation, nonverbal communication, and good old common sense. …