How to Check Ore Generation and World Gen Distributions with JER

One of JER's headline features is showing you where ores actually spawn in your world, so you can stop digging blindly. This guide covers reading those graphs.

Opening the Ore Gen View

In JEI, search for an ore block or its drop (for example, an ore block or the raw material). Hover the entry and open the JER World Gen tab. You'll see a graph plotting the ore's spawn distribution against Y-level. The horizontal axis represents height, and the bars show how common the ore is at each level. Peaks mean the ore is densest there; gaps mean it doesn't spawn at all in that range.

Interpreting the Graph

• A single tall peak means the ore concentrates at one Y-level band.
• Multiple peaks mean the ore spawns in more than one range (common for ores that appear both deep and shallow).
• The graph reflects the current pack's configuration, not vanilla defaults, so it's accurate for your setup.

Using It to Mine Smarter

Pick the Y-level at the tallest bar and branch mine around there. If you're hunting a specific ore, check its graph before you start a tunnel. For pack makers, these graphs are driven by the mod's world-gen config, so what you see is what the world will actually generate. If a graph is missing, that ore likely isn't registered with a world-gen entry.