--- ../src-base/minecraft/net/minecraft/world/gen/ChunkProviderServer.java
+++ ../src-work/minecraft/net/minecraft/world/gen/ChunkProviderServer.java
@@ -35,6 +35,7 @@
     public final IChunkLoader field_73247_e;
     public final Long2ObjectMap<Chunk> field_73244_f = new Long2ObjectOpenHashMap<Chunk>(8192);
     public final WorldServer field_73251_h;
+    private final Set<Long> loadingChunks = com.google.common.collect.Sets.newHashSet();
 
     public ChunkProviderServer(WorldServer p_i46838_1_, IChunkLoader p_i46838_2_, IChunkGenerator p_i46838_3_)
     {
@@ -85,20 +86,47 @@
     @Nullable
     public Chunk func_186028_c(int p_186028_1_, int p_186028_2_)
     {
-        Chunk chunk = this.func_186026_b(p_186028_1_, p_186028_2_);
+        return loadChunk(p_186028_1_, p_186028_2_, null);
+    }
 
+    @Nullable
+    public Chunk loadChunk(int p_186028_1_, int p_186028_2_, @Nullable Runnable runnable)
+    {
+        Chunk chunk = this.func_186026_b(p_186028_1_, p_186028_2_);
         if (chunk == null)
         {
-            chunk = this.func_73239_e(p_186028_1_, p_186028_2_);
-
-            if (chunk != null)
+            long pos = ChunkPos.func_77272_a(p_186028_1_, p_186028_2_);
+            chunk = net.minecraftforge.common.ForgeChunkManager.fetchDormantChunk(pos, this.field_73251_h);
+            if (chunk != null || !(this.field_73247_e instanceof net.minecraft.world.chunk.storage.AnvilChunkLoader))
             {
+                if (!loadingChunks.add(pos)) net.minecraftforge.fml.common.FMLLog.bigWarning("There is an attempt to load a chunk ({},{}) in dimension {} that is already being loaded. This will cause weird chunk breakages.", p_186028_1_, p_186028_2_, this.field_73251_h.field_73011_w.getDimension());
+                if (chunk == null) chunk = this.func_73239_e(p_186028_1_, p_186028_2_);
+
+                if (chunk != null)
+                {
                 this.field_73244_f.put(ChunkPos.func_77272_a(p_186028_1_, p_186028_2_), chunk);
                 chunk.func_76631_c();
                 chunk.func_186030_a(this, this.field_186029_c);
+                }
+
+                loadingChunks.remove(pos);
             }
+            else
+            {
+                net.minecraft.world.chunk.storage.AnvilChunkLoader loader = (net.minecraft.world.chunk.storage.AnvilChunkLoader) this.field_73247_e;
+                if (runnable == null || !net.minecraftforge.common.ForgeChunkManager.asyncChunkLoading)
+                    chunk = net.minecraftforge.common.chunkio.ChunkIOExecutor.syncChunkLoad(this.field_73251_h, loader, this, p_186028_1_, p_186028_2_);
+                else if (loader.func_191063_a(p_186028_1_, p_186028_2_))
+                {
+                    // We can only use the async queue for already generated chunks
+                    net.minecraftforge.common.chunkio.ChunkIOExecutor.queueChunkLoad(this.field_73251_h, loader, this, p_186028_1_, p_186028_2_, runnable);
+                    return null;
+                }
+            }
         }
 
+        // If we didn't load the chunk async and have a callback run it now
+        if (runnable != null) runnable.run();
         return chunk;
     }