diff --git a/biomes.lua b/biomes.lua
index c3cd583..7896fb1 100644
--- a/biomes.lua
+++ b/biomes.lua
@@ -18,16 +18,6 @@ local c_cavern_fungi = minetest.get_content_id("dfcaverns:cavern_fungi") -- para
 local c_dirt_moss = minetest.get_content_id("dfcaverns:dirt_with_cave_moss")
 local c_cobble_fungus = minetest.get_content_id("dfcaverns:cobble_with_floor_fungus")
 
-
-dfcaverns.config.ymax = subterrane.config.ymax
-
-dfcaverns.config.level1_min = -600
-dfcaverns.config.level2_min = -1000
-dfcaverns.config.level3_min = -1400
-dfcaverns.config.lava_sea_min = -1600
-
-dfcaverns.config.ymin = subterrane.config.ymin
-
 -- default mapgen registers an "underground" biome that gets in the way of everything.
 subterrane:override_biome({
 	name = "underground",
@@ -37,6 +27,30 @@ subterrane:override_biome({
 	humidity_point = 50,
 })
 
+subterrane:set_tcave_array({
+	{dfcaverns.config.ymax, 1.5},
+	{dfcaverns.config.ymax-100, 0.5},
+	
+	{dfcaverns.config.level1_min+100, 0.5},
+	{dfcaverns.config.level1_min, 1.0},
+	{dfcaverns.config.level1_min-100, 0.5},
+	
+	{dfcaverns.config.level2_min+100, 0.5},
+	{dfcaverns.config.level2_min, 1.0},
+	{dfcaverns.config.level2_min-100, 0.5},
+
+	{dfcaverns.config.level3_min+100, 0.5},
+	{dfcaverns.config.level3_min, 1.0},
+	{dfcaverns.config.level3_min-100, 0.5},
+
+	{dfcaverns.config.lava_sea_min+100, 0.5},
+	{dfcaverns.config.lava_sea_min, 1.0},
+	{dfcaverns.config.lava_sea_min-100, 0.5},
+
+	{dfcaverns.config.ymin+100, 0.5},
+	{dfcaverns.config.ymin, 1.5},
+})
+
 dfcaverns.can_support_vegetation = {[c_sand] = true, [c_dirt] = true, [c_coal_ore] = true, [c_gravel] = true}
 
 dfcaverns.place_shrub = function(data, vi, param2_data)
diff --git a/biomes/level1.lua b/biomes/level1.lua
index 4bf69ef..a301063 100644
--- a/biomes/level1.lua
+++ b/biomes/level1.lua
@@ -12,7 +12,6 @@ local c_cavern_fungi = minetest.get_content_id("dfcaverns:cavern_fungi") -- para
 local subsea_level = (dfcaverns.config.level1_min - dfcaverns.config.ymax) * 0.3 + dfcaverns.config.level1_min
 
 local level_1_tower_cap_floor = function(area, data, ai, vi, bi, param2_data)
-	subterrane:obsidian_floor_dam(area, data, ai, vi, bi)
 	if data[bi] ~= c_stone then
 		return
 	end
@@ -37,7 +36,6 @@ local level_1_tower_cap_floor = function(area, data, ai, vi, bi, param2_data)
 end
 
 local level_1_moist_ceiling = function(area, data, ai, vi, bi, param2_data)
-	subterrane:obsidian_ceiling_plug(area, data, ai, vi, bi)
 	if data[ai] ~= c_stone then
 		return
 	end
@@ -124,7 +122,6 @@ end
 
 
 local level_1_fungiwood_floor = function(area, data, ai, vi, bi, param2_data)
-	subterrane:obsidian_floor_dam(area, data, ai, vi, bi)
 	if data[bi] ~= c_stone then
 		return
 	end
@@ -204,6 +201,7 @@ minetest.register_biome({
 	_subterrane_fill_node = c_water,
 	_subterrane_cave_fill_node = c_water,
 	_subterrane_floor_decor = level_1_underwater_floor,
+	_subterrane_mitigate_lava = false, -- no need to mitigate lava in a flooded cave, problem is self-solving
 })
 
 minetest.register_biome({
@@ -216,9 +214,9 @@ minetest.register_biome({
 	_subterrane_floor_decor = level_1_wet_floor,
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_fill_node = c_water,
+	_subterrane_mitigate_lava = true,
 })
 
-
 minetest.register_biome({
 	name = "dfcaverns_level1_tower_cap_biome_lower",
 	y_min = dfcaverns.config.level1_min,
@@ -230,6 +228,7 @@ minetest.register_biome({
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_floor_decor = level_1_cave_floor,
 	_subterrane_cave_ceiling_decor = level_1_cave_ceiling,
+	_subterrane_mitigate_lava = true,
 })
 
 minetest.register_biome({
@@ -243,6 +242,7 @@ minetest.register_biome({
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_floor_decor = level_1_cave_floor,
 	_subterrane_cave_ceiling_decor = level_1_cave_ceiling,
+	_subterrane_mitigate_lava = true,
 })
 
 minetest.register_biome({
@@ -256,6 +256,7 @@ minetest.register_biome({
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_floor_decor = level_1_cave_floor,
 	_subterrane_cave_ceiling_decor = level_1_cave_ceiling,
+	_subterrane_mitigate_lava = true,
 })
 
 minetest.register_biome({
@@ -269,6 +270,7 @@ minetest.register_biome({
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_floor_decor = level_1_cave_floor,
 	_subterrane_cave_ceiling_decor = level_1_cave_ceiling,
+	_subterrane_mitigate_lava = true,
 })
 
 minetest.register_biome({
@@ -280,6 +282,7 @@ minetest.register_biome({
 	_subterrane_ceiling_decor = level_1_dry_ceiling,
 	_subterrane_floor_decor = level_1_dry_floor,
 	_subterrane_fill_node = c_air,
+	_subterrane_mitigate_lava = false, -- let the lava spill in, nothing to protect
 })
 
 minetest.register_biome({
@@ -291,4 +294,5 @@ minetest.register_biome({
 	_subterrane_ceiling_decor = level_1_dry_ceiling,
 	_subterrane_floor_decor = level_1_dry_floor,
 	_subterrane_fill_node = c_air,
+	_subterrane_mitigate_lava = false, -- let the lava spill in, nothing to protect
 })
\ No newline at end of file
diff --git a/biomes/level2.lua b/biomes/level2.lua
index fc9f954..c37e67d 100644
--- a/biomes/level2.lua
+++ b/biomes/level2.lua
@@ -19,7 +19,6 @@ local subsea_level = (dfcaverns.config.level2_min - dfcaverns.config.level1_min)
 
 
 local level_2_tower_cap_floor = function(area, data, ai, vi, bi, param2_data)
-	subterrane:obsidian_floor_dam(area, data, ai, vi, bi)
 	if data[bi] ~= c_stone then
 		return
 	end
@@ -44,7 +43,6 @@ local level_2_tower_cap_floor = function(area, data, ai, vi, bi, param2_data)
 end
 
 local level_2_moist_ceiling = function(area, data, ai, vi, bi, param2_data)
-	subterrane:obsidian_ceiling_plug(area, data, ai, vi, bi)
 	if data[ai] ~= c_stone then
 		return
 	end
@@ -131,7 +129,6 @@ end
 
 
 local level_2_fungiwood_floor = function(area, data, ai, vi, bi, param2_data)
-	subterrane:obsidian_floor_dam(area, data, ai, vi, bi)
 	if data[bi] ~= c_stone then
 		return
 	end
@@ -157,7 +154,6 @@ local level_2_fungiwood_floor = function(area, data, ai, vi, bi, param2_data)
 end
 
 local level_2_tunnel_tube_floor = function(area, data, ai, vi, bi, param2_data)
-	subterrane:obsidian_floor_dam(area, data, ai, vi, bi)
 	if data[bi] ~= c_stone then
 		return
 	end
@@ -183,7 +179,6 @@ local level_2_tunnel_tube_floor = function(area, data, ai, vi, bi, param2_data)
 end
 
 local level_2_spore_tree_floor = function(area, data, ai, vi, bi, param2_data)
-	subterrane:obsidian_floor_dam(area, data, ai, vi, bi)
 	if data[bi] ~= c_stone then
 		return
 	end
@@ -209,7 +204,6 @@ local level_2_spore_tree_floor = function(area, data, ai, vi, bi, param2_data)
 end
 
 local level_2_goblin_cap_floor = function(area, data, ai, vi, bi, param2_data)
-	subterrane:obsidian_floor_dam(area, data, ai, vi, bi)
 	if data[bi] ~= c_stone then
 		return
 	end
@@ -288,6 +282,7 @@ minetest.register_biome({
 	_subterrane_fill_node = c_water,
 	_subterrane_cave_fill_node = c_water,
 	_subterrane_floor_decor = level_2_underwater_floor,
+	_subterrane_mitigate_lava = false,
 })
 
 minetest.register_biome({
@@ -300,6 +295,7 @@ minetest.register_biome({
 	_subterrane_floor_decor = level_2_wet_floor,
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_fill_node = c_water,
+	_subterrane_mitigate_lava = true,
 })
 
 
@@ -314,6 +310,7 @@ minetest.register_biome({
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_floor_decor = level_2_cave_floor,
 	_subterrane_cave_ceiling_decor = level_2_cave_ceiling,
+	_subterrane_mitigate_lava = true,
 })
 
 minetest.register_biome({
@@ -327,6 +324,7 @@ minetest.register_biome({
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_floor_decor = level_2_cave_floor,
 	_subterrane_cave_ceiling_decor = level_2_cave_ceiling,
+	_subterrane_mitigate_lava = true,
 })
 
 minetest.register_biome({
@@ -340,6 +338,7 @@ minetest.register_biome({
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_floor_decor = level_2_cave_floor,
 	_subterrane_cave_ceiling_decor = level_2_cave_ceiling,
+	_subterrane_mitigate_lava = true,
 })
 
 minetest.register_biome({
@@ -353,6 +352,7 @@ minetest.register_biome({
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_floor_decor = level_2_cave_floor,
 	_subterrane_cave_ceiling_decor = level_2_cave_ceiling,
+	_subterrane_mitigate_lava = true,
 })
 
 minetest.register_biome({
@@ -366,6 +366,7 @@ minetest.register_biome({
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_floor_decor = level_2_cave_floor,
 	_subterrane_cave_ceiling_decor = level_2_cave_ceiling,
+	_subterrane_mitigate_lava = true,
 })
 
 minetest.register_biome({
@@ -379,6 +380,7 @@ minetest.register_biome({
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_floor_decor = level_2_cave_floor,
 	_subterrane_cave_ceiling_decor = level_2_cave_ceiling,
+	_subterrane_mitigate_lava = true,
 })
 
 
@@ -393,6 +395,7 @@ minetest.register_biome({
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_floor_decor = level_2_cave_floor,
 	_subterrane_cave_ceiling_decor = level_2_cave_ceiling,
+	_subterrane_mitigate_lava = true,
 })
 
 minetest.register_biome({
@@ -406,10 +409,9 @@ minetest.register_biome({
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_floor_decor = level_2_cave_floor,
 	_subterrane_cave_ceiling_decor = level_2_cave_ceiling,
+	_subterrane_mitigate_lava = true,
 })
 
-
-
 minetest.register_biome({
 	name = "dfcaverns_level2_tunnel_tube_biome_lower",
 	y_min = dfcaverns.config.level2_min,
@@ -421,6 +423,7 @@ minetest.register_biome({
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_floor_decor = level_2_cave_floor,
 	_subterrane_cave_ceiling_decor = level_2_cave_ceiling,
+	_subterrane_mitigate_lava = true,
 })
 
 minetest.register_biome({
@@ -434,9 +437,9 @@ minetest.register_biome({
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_floor_decor = level_2_cave_floor,
 	_subterrane_cave_ceiling_decor = level_2_cave_ceiling,
+	_subterrane_mitigate_lava = true,
 })
 
-
 minetest.register_biome({
 	name = "dfcaverns_level2_dry_biome_lower",
 	y_min = dfcaverns.config.level2_min,
@@ -446,6 +449,7 @@ minetest.register_biome({
 	_subterrane_ceiling_decor = level_2_dry_ceiling,
 	_subterrane_floor_decor = level_2_dry_floor,
 	_subterrane_fill_node = c_air,
+	_subterrane_mitigate_lava = false,
 })
 
 minetest.register_biome({
@@ -457,4 +461,5 @@ minetest.register_biome({
 	_subterrane_ceiling_decor = level_2_dry_ceiling,
 	_subterrane_floor_decor = level_2_dry_floor,
 	_subterrane_fill_node = c_air,
+	_subterrane_mitigate_lava = false,
 })
\ No newline at end of file
diff --git a/biomes/level3.lua b/biomes/level3.lua
index ff14ce5..c792de7 100644
--- a/biomes/level3.lua
+++ b/biomes/level3.lua
@@ -44,7 +44,6 @@ local level_3_blood_thorn_floor = function(area, data, ai, vi, bi, param2_data)
 end
 
 local level_3_moist_ceiling = function(area, data, ai, vi, bi, param2_data)
-	subterrane:obsidian_ceiling_plug(area, data, ai, vi, bi)
 	if data[ai] ~= c_stone then
 		return
 	end
@@ -297,6 +296,7 @@ minetest.register_biome({
 	_subterrane_floor_decor = level_3_wet_floor,
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_fill_node = c_water,
+	_subterrane_mitigate_lava = true,
 })
 
 
@@ -311,6 +311,7 @@ minetest.register_biome({
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_floor_decor = level_3_cave_floor,
 	_subterrane_cave_ceiling_decor = level_3_cave_ceiling,
+	_subterrane_mitigate_lava = true,
 })
 
 minetest.register_biome({
@@ -324,6 +325,7 @@ minetest.register_biome({
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_floor_decor = level_3_cave_floor,
 	_subterrane_cave_ceiling_decor = level_3_cave_ceiling,
+	_subterrane_mitigate_lava = true,
 })
 
 minetest.register_biome({
@@ -337,6 +339,7 @@ minetest.register_biome({
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_floor_decor = level_3_cave_floor,
 	_subterrane_cave_ceiling_decor = level_3_cave_ceiling,
+	_subterrane_mitigate_lava = true,
 })
 
 minetest.register_biome({
@@ -350,6 +353,7 @@ minetest.register_biome({
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_floor_decor = level_3_cave_floor,
 	_subterrane_cave_ceiling_decor = level_3_cave_ceiling,
+	_subterrane_mitigate_lava = true,
 })
 
 minetest.register_biome({
@@ -363,6 +367,7 @@ minetest.register_biome({
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_floor_decor = level_3_cave_floor,
 	_subterrane_cave_ceiling_decor = level_3_cave_ceiling,
+	_subterrane_mitigate_lava = true,
 })
 
 minetest.register_biome({
@@ -376,9 +381,9 @@ minetest.register_biome({
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_floor_decor = level_3_cave_floor,
 	_subterrane_cave_ceiling_decor = level_3_cave_ceiling,
+	_subterrane_mitigate_lava = true,
 })
 
-
 minetest.register_biome({
 	name = "dfcaverns_level3_spore_tree_biome_lower",
 	y_min = dfcaverns.config.level3_min,
@@ -390,6 +395,7 @@ minetest.register_biome({
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_floor_decor = level_3_cave_floor,
 	_subterrane_cave_ceiling_decor = level_3_cave_ceiling,
+	_subterrane_mitigate_lava = true,
 })
 
 minetest.register_biome({
@@ -403,6 +409,7 @@ minetest.register_biome({
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_floor_decor = level_3_cave_floor,
 	_subterrane_cave_ceiling_decor = level_3_cave_ceiling,
+	_subterrane_mitigate_lava = true,
 })
 
 minetest.register_biome({
@@ -416,6 +423,7 @@ minetest.register_biome({
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_floor_decor = level_3_cave_floor,
 	_subterrane_cave_ceiling_decor = level_3_cave_ceiling,
+	_subterrane_mitigate_lava = true,
 })
 
 minetest.register_biome({
@@ -429,6 +437,7 @@ minetest.register_biome({
 	_subterrane_fill_node = c_air,
 	_subterrane_cave_floor_decor = level_3_cave_floor,
 	_subterrane_cave_ceiling_decor = level_3_cave_ceiling,
+	_subterrane_mitigate_lava = true,
 })
 
 
@@ -441,6 +450,7 @@ minetest.register_biome({
 	_subterrane_ceiling_decor = level_3_dry_ceiling,
 	_subterrane_floor_decor = level_3_dry_floor,
 	_subterrane_fill_node = c_air,
+	_subterrane_mitigate_lava = false,
 })
 
 minetest.register_biome({
@@ -452,4 +462,5 @@ minetest.register_biome({
 	_subterrane_ceiling_decor = level_3_dry_ceiling,
 	_subterrane_floor_decor = level_3_dry_floor,
 	_subterrane_fill_node = c_air,
+	_subterrane_mitigate_lava = false,
 })
\ No newline at end of file
diff --git a/config.lua b/config.lua
index 1d1ca63..9ac6f87 100644
--- a/config.lua
+++ b/config.lua
@@ -63,4 +63,12 @@ for _, plant in pairs(plants) do
 	setting("float", plant.name.."_timer_multiplier", plant.delay_multiplier, plant.name.." growth delay multiplier")
 end
 
-setting("bool", "light_kills_fungus", true, "Light kills fungus")
\ No newline at end of file
+setting("bool", "light_kills_fungus", true, "Light kills fungus")
+
+setting("int", "ymax", -300, "Upper limit of level 1")
+setting("int", "level1_min", -600, "Upper limit of level 2")
+setting("int", "level2_min", -1000, "Upper limit of level 3")
+setting("int", "level3_min", -1400, "Upper limit of lava sea")
+setting("int", "lava_sea_min", -1600, "Upper limit of underworld")
+setting("int", "ymin", -2000, "Lower limit of underworld")
+
diff --git a/depends.txt b/depends.txt
index 01d2a43..d419617 100644
--- a/depends.txt
+++ b/depends.txt
@@ -1,3 +1,4 @@
 default
 subterrane
-farming
\ No newline at end of file
+farming
+harderstone?
\ No newline at end of file
diff --git a/init.lua b/init.lua
index 1cbe030..49ed68f 100644
--- a/init.lua
+++ b/init.lua
@@ -59,9 +59,8 @@ minetest.register_ore({
 		"default:dirt_with_grass",
 		"default:dirt_with_dry_grass",
 		"default:dirt_with_snow",
-		"default:cobble",
-		"default:mossycobble",
-	},
+		"harderstone:weak_stone",
+		},
 	column_height_min = 2,
 	column_height_max = 6,
 	height_min = -31000,