buying compressor use for gold mine

hey Cas how ru doin ,i am louie from Arusha Tanzania i am looking into investing into buying a used compressor thats oil cooled for hire and servicing a gold mine site here in Tanzania where i could servive upto to four sites at a go , we realy dont av good mechanical engineers around so i need something that i reliable and durable,Can you please advice me.I av been told Duetz compressor i don realy knw about them bt watz ur take on that?Hope to hear from u soon.heres my no. +2******** and my email *********@gmail.com