... 1-3meter hole diameter:50cm work speed: within 1min/hole Drilling Machine Tractor digging machine design full hydraulic,High working efficiency ... of geological layers: Loess layer,argillic horizon ,Sandy soil with gravel,Weathering of rock and soil,Frozen layer not applicable ... hole,drill,bore,pile,Solar photovoltaic solar panels Bracket drilling hole,Street rod diggind hole,Easy to operate,