Early ore/diamond/autoprocessing farm, 20 diamonds per hour ... Reddit
It's called Sluice. AFAIK, it's a custom mod made for this modpack. It sifts through sand/dust/gravel and similar mats and produces chunks of ore, gems etc. The two blocks underneath the smeltery are a trash can (gets rid of excess lava) and a Jar Autoprocessing block which just repeats the same crafting recipe.