Nurses at a Duluth hospital have set a strike date.  90-percent of the roughly one-thousand nurses at SMDC/Essentia Health System voted last month to authorize a strike. That strike date has now been set for September 14th, though the nurses union and federal mediators will meet again next week. The key sticking point remains staffing levels, similar to what prompted a one-day strike of Twin Cities nurses in June. The Minnesota Nurses Association and officials with Duluth’s St. Luke’s Hospital reached a deal earlier this week, averting a strike there.