What a beautiful photo - bravo! I can't help but think, however, that it might be a tad better if the person at the far left was cropped out (or was entirely within the frame).
But that would make for a much more static composition in this lovely work. My choice would be to tighten the crop on the right, transecting the right shoulder of the figure in red, which would add another dynamic element - figures moving into and out of the frame, and off-setting the overseer more.
The impressionists (Degas and Manet come to mind) used the canvas edges so effectively to give life and movement to their figures, with transected bodies and even disembodied limbs adding motion and mystery to their works.
PB