A drilling rig system comprising: three or more base towers spaced apart in a selected layout; a horizontal base frame interconnecting lower regions of the base towers to form a base structure; a drill floor overlying the horizontal base frame and vertically movable relative thereto, the drill floor incorporating a plurality of floor-lifting sheave assemblies (32A, 32B), each said floor-lifting sheave assembly being associated with one of the base towers; a rig mast on the drill floor, including a drawworks and a traveling block; a plurality of floor-lifting cables, each floor-lifting cable being associated with one of the base towers, a first end of each said floor-lifting cable being anchored to an upper region of the associated base tower, each floor-lifting cable being threaded around the floor-lifting sheave assembly of its associated base tower, and a second end of each cable extending upward to engage the traveling block; and drill floor guide means to mate the drill floor to each of the base towers, whereupon actuation of the drawworks will cause the traveling block to move upward within the rig mast, to thereby lift the drill floor relative to the base structure until the drill floor is at a desired elevation, the mating of the drill floor to each of the base towers via the drill floor guide means causing the drill floor to be lifted in a uniform vertical movement relative to the base towers, whilst the base towers provide lateral stability to the drill floor, during the lifting process; and anchorage means for locking the drill floor to the base towers to maintain the drill floor at the desired elevation. three or more base towers spaced apart in a selected layout; a horizontal base frame interconnecting lower regions of the base towers to form a base structure; a drill floor overlying the horizontal base frame and vertically movable relative thereto, the drill floor incorporating a plurality of floor-lifting sheave assemblies (32A, 32B), each said floor-lifting sheave assembly being associated with one of the base towers; a rig mast on the drill floor, including a drawworks and a traveling block; a plurality of floor-lifting cables, each floor-lifting cable being associated with one of the base towers, a first end of each said floor-lifting cable being anchored to an upper region of the associated base tower, each floor-lifting cable being threaded around the floor-lifting sheave assembly of its associated base tower, and a second end of each cable extending upward to engage the traveling block; and drill floor guide means to mate the drill floor to each of the base towers, whereupon actuation of the drawworks will cause the traveling block to move upward within the rig mast, to thereby lift the drill floor relative to the base structure until the drill floor is at a desired elevation, the mating of the drill floor to each of the base towers via the drill floor guide means causing the drill floor to be lifted in a uniform vertical movement relative to the base towers, whilst the base towers provide lateral stability to the drill floor, during the lifting process; and anchorage means for locking the drill floor to the base towers to maintain the drill floor at the desired elevation.