Efficient Mining in Luanti

I'm writing this to explain how I mine efficiently, and also because I don't see much talk about this method. By "efficient mining" I mean a pattern of mining that results in the most ore extraction in a given volume of rock with as little removal of rock as practicable. In other words, what is the minimum amount of rock that can be removed to gain access to all of the ores?

Below is a grid view from the side that shows a pattern of mining that accomplishes the task of exposing all blocks in a given area. The view is from the side looking into the tunnels. The tunnels are 1x2 and can be of any length. They are spaced every fourth block horizontally.  Every two blocks down vertically, the tunnels are offset horizontally by two blocks.

This pattern can go on indefinitely in all directions. As long as it is maintained it will expose every block for mining without stripping out all of the rock. Besides minimizing my cobble stocks, I also like using it because it leaves behind a collection of hallways which I find more interesting, and less disruptive, than expansive holes.

Conceptualizing this pattern is easier than mining it. Since there are zero rows of blocks in between the floors of the tunnels, a hallway connecting the tunnels will have blocks missing in its floor from the tunnels below. One can give up on hallways and only connect the tunnels diagonally from floor to floor by stairs, but this leads to confusing navigation. Instead, I mine in a manner that minimizes the impact of the holes created at the intersections of hallways and tunnels.

First, I mine one layer of tunnels with a hallway connecting both ends. These tunnels can be of any length and typically I make them much longer than is shown here. This orthographic view shows four mining tunnels connected by two hallways at either end.

Then my next level of tunnels is dug four blocks lower. These tunnels line up horizontally with the first level of tunnels. Notice that so far all the tunnels and hallways have floors that are intact. 

This pattern can go on for as long as I want in all directions. It will mine out a lot of the ore, but not all of it. Here is how it looks so far in 2D looking down the tunnels like in the first illustration. 

Here we see the unmined space between the two floors of tunnels. To make a set of tunnels offset from the floors above and below, I dig my first tunnel halfway down the stairs. From there I dig the hallways that will connect the tunnels followed by the tunnels themselves.

Notice in this next illustration how as soon as I start the first tunnel a hole opens up in the floor above, and the first block of the floor is missing due to the hallway below. When I dig my hallways to connect the tunnels additional gaps in the floor open up as I cross the tunnels below. Likewise, gaps appear in the floor above. These one block gaps in the floor are visually displeasing, but they are easily walked over. Notice also that I have to offset the location of the hallway because otherwise it wouldn't have a floor due to the hallway below it. It's difficult to illustrate all of this, but I hope this is enough to give an idea of what to expect.

Conclusion 

So, there you go. This is how I mine. There are of course variations possible. For example, the first hallways on the top and bottom levels could be placed on the other side of the stairs. This would have prevented the first set of holes when digging the first tunnel on the in-between level. That might seem like an advantage, but it only lasts until I decide to extend the tunnels through the hallway to the other side. Then the same number of holes will open up.

Remember that this is only a basic pattern which can be extended in any direction. It is adjustable to deal with caverns and other obstacles.

I hope this is helpful. Happy mining!