Employee strained a shoulder when they lost footing while attempting to install a roof bolt. EE continued to work through 3/28/20 at which time the mine was idled. EE was on furlough through 5/4/20 when the mine partially reopened. Due to the Covid 19 Pandemic, EE elected to be self excluded and remain on furlough. EE started missing work on 7/27/20 when the mine reopened.