diff --git a/games/minimal/mods/default/mapgen.lua b/games/minimal/mods/default/mapgen.lua
new file mode 100644
index 000000000..af94505a0
--- /dev/null
+++ b/games/minimal/mods/default/mapgen.lua
@@ -0,0 +1,114 @@
+-- minetest/default/mapgen.lua
+
+--
+-- Aliases for map generator outputs
+--
+
+minetest.register_alias("mapgen_air", "air")
+minetest.register_alias("mapgen_stone", "default:stone")
+minetest.register_alias("mapgen_tree", "default:tree")
+minetest.register_alias("mapgen_leaves", "default:leaves")
+minetest.register_alias("mapgen_apple", "default:apple")
+minetest.register_alias("mapgen_water_source", "default:water_source")
+minetest.register_alias("mapgen_dirt", "default:dirt")
+minetest.register_alias("mapgen_sand", "default:sand")
+minetest.register_alias("mapgen_gravel", "default:gravel")
+minetest.register_alias("mapgen_clay", "default:clay")
+minetest.register_alias("mapgen_lava_source", "default:lava_source")
+minetest.register_alias("mapgen_cobble", "default:cobble")
+minetest.register_alias("mapgen_mossycobble", "default:mossycobble")
+minetest.register_alias("mapgen_dirt_with_grass", "default:dirt_with_grass")
+minetest.register_alias("mapgen_junglegrass", "default:junglegrass")
+minetest.register_alias("mapgen_stone_with_coal", "default:stone_with_coal")
+minetest.register_alias("mapgen_stone_with_iron", "default:stone_with_iron")
+minetest.register_alias("mapgen_mese", "default:mese")
+
+--
+-- Ore generation
+--
+
+local function generate_ore(name, wherein, minp, maxp, seed, chunks_per_volume, ore_per_chunk, height_min, height_max)
+	if maxp.y < height_min or minp.y > height_max then
+		return
+	end
+	local y_min = math.max(minp.y, height_min)
+	local y_max = math.min(maxp.y, height_max)
+	local volume = (maxp.x-minp.x+1)*(y_max-y_min+1)*(maxp.z-minp.z+1)
+	local pr = PseudoRandom(seed)
+	local num_chunks = math.floor(chunks_per_volume * volume)
+	local chunk_size = 3
+	if ore_per_chunk <= 4 then
+		chunk_size = 2
+	end
+	local inverse_chance = math.floor(chunk_size*chunk_size*chunk_size / ore_per_chunk)
+	--print("generate_ore num_chunks: "..dump(num_chunks))
+	for i=1,num_chunks do
+		local y0 = pr:next(y_min, y_max-chunk_size+1)
+		if y0 >= height_min and y0 <= height_max then
+			local x0 = pr:next(minp.x, maxp.x-chunk_size+1)
+			local z0 = pr:next(minp.z, maxp.z-chunk_size+1)
+			local p0 = {x=x0, y=y0, z=z0}
+			for x1=0,chunk_size-1 do
+			for y1=0,chunk_size-1 do
+			for z1=0,chunk_size-1 do
+				if pr:next(1,inverse_chance) == 1 then
+					local x2 = x0+x1
+					local y2 = y0+y1
+					local z2 = z0+z1
+					local p2 = {x=x2, y=y2, z=z2}
+					if minetest.env:get_node(p2).name == wherein then
+						minetest.env:set_node(p2, {name=name})
+					end
+				end
+			end
+			end
+			end
+		end
+	end
+	--print("generate_ore done")
+end
+
+minetest.register_on_generated(function(minp, maxp, seed)
+	generate_ore("default:stone_with_coal", "default:stone", minp, maxp, seed,   1/8/8/8,    5, -31000,  64)
+	generate_ore("default:stone_with_iron", "default:stone", minp, maxp, seed+1, 1/16/16/16, 5,   -5,   7)
+	generate_ore("default:stone_with_iron", "default:stone", minp, maxp, seed+2, 1/12/12/12, 5, -16,   -5)
+	generate_ore("default:stone_with_iron", "default:stone", minp, maxp, seed+3, 1/9/9/9,    5, -31000, -17)
+	-- Generate clay
+	if maxp.y >= 2 and minp.y <= 0 then
+		-- Assume X and Z lengths are equal
+		local divlen = 4
+		local divs = (maxp.x-minp.x)/divlen+1;
+		for divx=0+1,divs-1-1 do
+		for divz=0+1,divs-1-1 do
+			local cx = minp.x + math.floor((divx+0.5)*divlen)
+			local cz = minp.z + math.floor((divz+0.5)*divlen)
+			if minetest.env:get_node({x=cx,y=1,z=cz}).name == "default:water_source" and
+					minetest.env:get_node({x=cx,y=0,z=cz}).name == "default:sand" then
+				local is_shallow = true
+				local num_water_around = 0
+				if minetest.env:get_node({x=cx-divlen*2,y=1,z=cz+0}).name == "default:water_source" then
+					num_water_around = num_water_around + 1 end
+				if minetest.env:get_node({x=cx+divlen*2,y=1,z=cz+0}).name == "default:water_source" then
+					num_water_around = num_water_around + 1 end
+				if minetest.env:get_node({x=cx+0,y=1,z=cz-divlen*2}).name == "default:water_source" then
+					num_water_around = num_water_around + 1 end
+				if minetest.env:get_node({x=cx+0,y=1,z=cz+divlen*2}).name == "default:water_source" then
+					num_water_around = num_water_around + 1 end
+				if num_water_around >= 2 then
+					is_shallow = false
+				end	
+				if is_shallow then
+					for x1=-divlen,divlen do
+					for z1=-divlen,divlen do
+						if minetest.env:get_node({x=cx+x1,y=0,z=cz+z1}).name == "default:sand" then
+							minetest.env:set_node({x=cx+x1,y=0,z=cz+z1}, {name="default:clay"})
+						end
+					end
+					end
+				end
+			end
+		end
+		end
+	end
+end)
+