Do not get trapped into this shift roster of 4x4 permanent nights. It is totally debilitating and can have grave physical and phycological consequenses - FACT. I cannot comment on if they can force it upon you. But if they are forcing something its for a reason. You will have to examine your contract. However, with the complete fragmentation of the industry and lack of cohesion between employees even at a local level they will probably succeed. Get your compatriots together ignore the supposed financial reward and ensure you dont get trapped. Remmember make all your representations in duplicate to your management as soon as possible and if you have a union get them involved. Even if its only for legal reasons. They can tend to take their eye off the ball when negotiating. Good luck and I hope you stop the rot.