Are you sure you mean 'have been worked'? That's an unusual form, and quite different to 'have worked'. In that case 'worked' is an adjective, and refers to some object(s). They could be something like mines, or something like gemstones, or ductile metal. 'These mines have been worked before, but there is still some gold available'. 'These jade pieces have been worked roughly, but they still need finishing'. 'These springs have been worked too much, that's why they have broken'. 'have worked' is the present perfect conjugation for work. "I have worked in this job for seven years". "You have worked too hard, take a break!"