You've also got your 'hybrids' such as WTP and STS, (and I would lump LEI in that group as well), where there is a mining services arm as well as a more general contraction component.
Have thought about WTP several times (had a few nice contract wins of late) but the mining services component keeps me from taking a stake.
You also have companies like BIS, who are a specialty steel producer, but with around 70% of their output directed towards the mining industry.
