Here is the start position. It is an epic game, so we will play 15 turns(the length of a whip cycle) from this point:
The goal is to produce as many hammers as possible in those 15 turns. No padding stats by stacking whip anger or anything like that. Just good old fashioned killing of grassland mines.
The killing grassland mines option builds a settler for one turn then whips it and builds a library with the overflow plus some turns of production while regrowing. When it hits the happy cap, it starts a settler. Total hammers produced:
135 (library) + 149 (settler) + 89 (partial settler build) = 373 hammers
Also note that because of the ridiculous regrowth rate, this city had to work some sub par tiles while finishing the library at population 6 to avoid growing into unhappiness. I could have skewed these numbers further by switching to a settler immediately at population 6 and working only the premium tiles the whole time.
The second test attempts to avoid killing of grassland mines. So it builds a library for one turn then shifts production to settlers (which are going to be the highest hammer yield it can get with these tiles, until time expires) It produces 2 settlers in the time frame, and ends up with 8 overflow (that will be modified by the forge to be 10 overflow) that I am counting. Total hammers produced:
149 (settler) + 149 (settler) + 25 (partial library build) + 10 (overflow) = 333 hammers.
Admittedly, the second option produces a bit more commerce, but commerce is not the point of slavery. The first option produced 40 more hammers over 15 turns which is 2.67 hammers a turn. And it could have been worse if I arranged it so I only worked premium tiles the whole time.
Admittedly, this example is highly skewed in favor of killing the mines. But even if one of those clams was not improved it still would be superior to kill the mines.