Interesting video showing the process of sand casting type, filmed at the Type Museum in London.
The end result looks like it could be printed from, after a little finishing work.
https://youtu.be/ye9hQKjlzXo
Nice find. 144 points is a lot for lead type; we have wood type in that size.
Kind of reminds me of how Koreans used to make type (investment casting in brass or bronze) before Gutenberg invented the lead process.
Oh, and I guess they used the Monotype melting pot as a remelting furnace here.
This topic showed also on www.drukwerkindemarge.org:
see: http://drukwerkindemarge.org/gieten-in-zand-een-aanvulling/
here also the link to the site of the Korean printingmuseum:
see: http://jikjiworld.cheongju.go.kr/main/jikjiworld