Hi 1kiwiwriter,
This is a wonderful story. The tone is formal. It suits the story and plot very well. The reader is wondering what the children will get out of their day mining for gold. They will read to the last word to find out. The plot is straight forward and moves along logically. The story is about a group of children who take part in a fascinating school project. The story is narrative as opposed to conflict based. This is rare in literature and very interesting. There is no doubt about what is going on here. The characters are well developed and believable. They come across as real people. There is no dialogue but it is not needed here. The description is detailed and vivid. It puts the reader all the way into the story. I did come across one structural issue that needs your attention:

1) a catholic raised-"catholic" should begin with a capital letter.

The story is consistent in terms of point of view and tense. Great job.