Template:Back Staircase mining is a common mining technique for quickly reaching lower levels of the map while continuing to gather Stone. It essentially consists of mining downwards in such a way that the player can always climb back up to the mine entrance.
Since the player can only jump up one block at a time, the path can never drop down more than one block.
Example of a staircase mine.
Method
Straight
The most basic strategy is to mine in a straight line at a 45° angle downwards, moving one block across for every block down. To climb back up these stairs afterwards, you only need to hold down the jump key while moving forward.
After enough cobblestone (or wood) is collected, you can craft Stairs and place them at your downright tunnel. It will make the trip a lot smoother and easier (maybe faster?), without any need to jump
Spiral
Spiral staircases are slightly more complicated since they have frequent turns, but have the advantage of leading straight down. They also have the benefit of being more contained and give you a more targeted dig. The simplest design is a 3x3 horizontal grid. By digging one block down at a time, and moving around the perimiter of your 3x3 area, you will have enough head room as you move down the staircase. You can optionally leave the central column for a barrier, but it isn't necessary for the functionality of the staircase.
You can also add stairs to this setup as well, however due to the way stairs behave and align themselves, you might not always get what you expect. I find that in a spiral staircase situation, if you want smoothness, you might as well just use ladders.
Spiral (2x2)
1) Stand on the bottom-left block of your staircase. Dig one block down, so you have to hop to exit the stairs.
2) Mine the block/s in front of you and the block beneath. Drop down.
3) Turn 90 degrees. Periodically place torch above head when dark.
4) Repeat steps 2 and 3 until desired result achieved.