The commissioner may, during the summer season, provide employment for part of the inmates at the Brushy Mountain penitentiary in repairing or building any buildings that may be deemed necessary on the property, so that, in the event of the employment of a sufficient number of inmates of the Brushy Mountain penitentiary on the county roads, pikes, highways or railroads, the mining force at the Brushy Mountain penitentiary shall be reduced to not exceeding three hundred (300) men mining coal, burning coke and operating the mines during the road working season.