So without direct knowledge of the code I cannot say for sure, but it seems to me that the system for spawning in recipes and moulds in chests is completely random with no regard to how functional that item is in the early game.
This can result in players taking a long time to find early game and essential parts, such as simple handles and tool heads. Certainly, this has been the experience on my server, where we found all the heavy blade heads, many secondary recipes (pommels, etc) before we found a single simple tool head and we’re still lacking the metal plate, simple hammer head, shovel and chisel moulds!
I think some degree of weighting (or outright restrictions) need to be put in place on what recipes can spawn in what places to give players a higher likelihood on getting essential early game tools when they need them.
This could be accomplished fairly simply, by having chests that are either earlier in the mines and closer to the town be more likely to spawn essential, simple recipes and less likely to spawn complex and more ‘luxury’ recipes. Further out chests should be the inverse, less likely to spawn simple things and more likely to reward players for their exploration with complex, powerful recipes such as those fancy heavy blades.