The amount and quality of communication within the groups was excellent. I heard one girl say to the other, "Don't make the road perfect, it was a really rough road." All I did was explain to them what the project goal was and put them into mixed Minecraft ability groups and away they went. There was no need for anymore instruction. They were engaged.
The book they have read is called Journey to Jo'Burg: A South African Story. Immediately after I set them off onto Minecraft, one of the boys got on Google and searched for images of Johannesburg so that he knew what to build. He found a picture of a distinctive tower and set out creating it. Even if their reading comprehension does not show any statistically significant growth, the amount of other skills and contextual understanding that they are intuitively gathering is clearly beneficial.