Guide:Mining techniques

This guide will help you with mining in Terraria.

Shaft Mining
You can build shafts to connect disconnected caves. Build shafts if you can't proceed any further in the cave you're currently exploring, or as the safest way to explore them.

Digging through Water
If you're digging through water, you might drown and lose your coins. To prevent this consider bringing along some Gills Potion or a Diving Helmet. Additionally, as torches won't work underwater, consider bringing along some Glowsticks, Flare Gun or Cursed/Ichor Torches. To avoid drowning, tunnel into one of the walls then mine the two blocks above your head so that it forms an air pocket. Either jump or grapple up into the air pocket to restore Air.

When you come across water while digging downward, place blocks in the water where you want the walls of your tunnel. Sand and Silt can be useful here.

Once your tunnel is completely sealed off from the rest of the body of water, you'll need to drain the water inside of it's walls. If there is a cave nearby, you can dig an outlet to let the water drain into that. Otherwise, dig a cavity off to the side starting from the bottom of your tunnel. If you are digging sideways, you need to place blocks behind you before digging through the water to prevent flooding your tunnels.

If you have access to the Pumpss, you can use pumps to move water from it to any nearby cave or reservoir. Simply place an Inlet Pump at the lowest point of your tunnel and wire it to an Outlet Pump where you want the water to end up. Attach and use a lever to the circuit and watch as your tunnel is automatically drained of water.

Digging through Lava
No solid blocks can be placed in Lava, so digging through it can be a problem. If you need to dig through it, consider bringing a pickaxe that's capable of digging through Obsidian, as well as Obsidian Skin Potions and Sand or Silt. Additionally consider bringing along some Gills Potions.

This works much the same as digging through water, with the difference that lava can damage you. Sand or Silt blocks must be dropped into the lava in order to form the walls of your tunnel. If you want the walls to be made of some other material, drop them an additional block to either side, so you have room to place the permanent walls before reclaiming the temporary ones. You can then jump into the lava-flooded tunnel and drain the lava exactly as you would with water.

If you do not have protection from lava, you will have to tunnel around it and dig a reservoir to drain the lava from your tunnels into it. Finally, connect the reservoir the lowest part of the flooded section so that it drains completely.

Another way is to dig with the help of water. You need to flood your tunnels with water, so that there's enough of it to turn Lava into Obsidian. Newly formed Obsidian will become the walls of your tunnel, and can be replaced by digging them and using another block. As the tunnel is likely to be flooded you may want to seek ways for breathing underwater, like the Gills Potion or digging an air pocket. If you are doing this in the Underworld, water rapidly evaporates in it, so it must be replaced with Honey. This will however produce Crispy Honey Blocks instead of Obsidian.

Finding Traps
, although the most common type of traps, are somewhat rare. They can be found by using a dangersense potion. Alternatively, holding an electric item(or Mechanical Lens/The Grand Design) and finding horizontal lines of wiring is another idea (if the wire line is vertical it is probably a boulder trap). If the lines are short and not straight, it may be some explosives, statues or geysers. The geysers can only be found in lava layer and the statues are often near a chest, that can be detected by Metal Detector or higher.

Mining Hellstone
Digging through the Underworld presents unique challenges, particularly in managing the lava spawned when Hellstone is mined.

The fastest and easiest way is to use Obsidian Skin Potions, as you don't need to surround the Hellstone with blocks or move the lava. Furthermore, you can simply jump in one of the many lava lakes for easy access to the hellstone. This will also prevent most monsters from reaching you. One could use a Magic Mirror to quickly escape before the buff ends, granted the player doesn't die of fire damage.

Alternatively, you can surround the Hellstone veins completely with a layer of blocks. That way, when the hellstone is mined, the lava it leaves will be safely contained. While standing outside the barrier, mine the hellstone vein. If some hellstone is out of reach, drain the lava into a reservoir or move it with Pumps.

Using an artificial Meteor biome
If the Player places 50 pieces of Meteorite ore or more on the screen where they are mining, they can create an artificial Meteor Biome. In this biome, all monster spawns are replaced by Meteor Heads, which are more predictable, and tend to do less damage than the naturally spawning creatures of The Underworld. If the Player can withstand the Meteor Head attacks, they can mine Hellstone in relative peace.

Using the Spawning Limits
There is a hidden limit to the number of spawned enemies that can be spawned at once. You can use this to your advantage by simply not killing the enemies that are not a threat to you, but keeping them close enough to you that they don't despawn. This functionally prevents any actually threatening enemy from spawning, letting you dig at your own leisure.

The simplest way to accomplish this is to place dirt (or any other block you have in huge quantities) tunnels or dig tunnels in the ash while letting demons and bats fly around you just above. Don't kill them.

If a bone serpent spawns, it will be trouble, but you have time to regenerate once it is dead. If an imp spawns, either destroy its projectiles until it decides to teleport inside your tunnel, and kill it there, or use the Vilethorn to kill it from inside your tunnel.

Keep in mind that creatures need a certain amount of space to spawn - imps take a 2x3 tile area to spawn, and bats take 2x2. If you are worried about spawns in your tunnels, either place dirt/stone walls to prevent that, or else place dirt behind you so that no space larger than 2x2 is remaining.

The trick is to not go so far away that the demons or bats can despawn - it may actually be worthwhile to dig them a separate little access tunnel of their own, as well.

Once your spawn limits are hit, you can dig in peace using the "reservoir" method to find places to put the excess lava.

Using this method requires the most patience, but it can net the most profit, as you can loot basically as much of the Underworld in one go as you can carry.

Using natural Underworld structures
There are often Hellstone ore veins next to the Ruined Houses, and with the thin wall of Obsidian Brick between the Hellstone, this makes a great natural barrier. The player can mine most Hellstone ore veins, and if some of it is out of reach, mine a single block to drain the lake, as the house can function as reservoir.

Mining in Hardmode
After Defeating The Wall of Flesh, Hardmode Begins. New Difficult Enemies, Underground Corruption, Crimson and The Hallow will generate in your world. Mining recommended in Hardmode, especially for fighting Mechanical bosses.

First, break 3 Demon Altars for generating the hardmode ores:
 * First Altar: Cobalt Ore or Palladium Ore
 * Second Altar: Mythril Ore or Orichalcum Ore
 * Third Altar: Titanium Ore or Adamantite Ore

Most areas deep enough to spawn hardmode ores have significantly more powerful monsters in hardmode. Exercise caution while exploring new caverns, and avoid especially dangerous areas such as the Jungle.

Consider returning to the Underworld, which is now one of the safest biomes. Its ash ceiling can contain Titanium/Adamantite, and gaps in the ceiling give quick access to many deep caves. You may also have extra opportunities to fight the Wall of Flesh to collect additional drops, and to purify a Tax Collector.

If you have the patience, filling in caves with spare natural blocks is a good way to squeeze a little bit more ore out of your world.

End-Game Mining
If it's near the end of the game, and you still need to mine some more bars, then some good options are the Shroomite Digging Claw or the Picksaw. They have one of the fastest mining speeds in the game. Another nice option is the Laser Drill, due to its long range of 10 tiles, although it is not recommended as it does not benefit from any Melee speed buffs.

If you have beaten the Moon Lord, the Drill Containment Unit becomes available. Although rather expensive to make, this mount can mine large amounts of ore quickly and also slopes surrounding blocks, which provides a visual bonus. It can also hover and fly indefinitely.