Some minor maptweaks

maps/groundbase/groundbase_mining.dm

@@ -0,0 +1,51 @@
+/turf/simulated/mineral/vacuum/gb_mine/make_ore(var/rare_ore)
+	if(mineral)
+		return
+	var/mineral_name
+	if(rare_ore)
+		mineral_name = pickweight(list(
+			"marble" = 3,
+			"uranium" = 10,
+			"platinum" = 10,
+			"hematite" = 20,
+			"carbon" = 5,
+			"diamond" = 1,
+			"gold" = 8,
+			"silver" = 8,
+			"phoron" = 18,
+			"lead" = 2,
+			"verdantium" = 1))
+	else
+		mineral_name = pickweight(list(
+			"marble" = 2,
+			"uranium" = 5,
+			"platinum" = 5,
+			"hematite" = 35,
+			"carbon" = 5,
+			"gold" = 3,
+			"silver" = 3,
+			"phoron" = 25,
+			"lead" = 1))
+
+	if(mineral_name && (mineral_name in GLOB.ore_data))
+		mineral = GLOB.ore_data[mineral_name]
+		UpdateMineral()
+	update_icon()
+
+/datum/random_map/noise/ore/mining
+	descriptor = "asteroid field ore distribution map"
+	deep_val = 0.2
+	rare_val = 0.1
+
+/datum/random_map/noise/ore/mining/check_map_sanity()
+	return 1 //Totally random, but probably beneficial.
+
+/area/gb_mine/
+	ambience = list('sound/ambience/ambimine.ogg', 'sound/ambience/song_game.ogg')
+	base_turf = /turf/simulated/mineral/floor/vacuum
+/area/gb_mine/unexplored
+	name = "Virgo 3c Underground"
+	icon_state = "unexplored"
+/area/gb_mine/explored
+	name = "Virgo 3c Underground"
+	icon_state = "explored"