I usually avoid surface holes or ravines in deserts because It is such a hassle to avoid cave-ins. In my current world I’m experimenting with purposefully caving-in unsupported sand in a large cave near the surface so I end up with a safe place to dig out. I’ve tried adding a layer of cobblestone under overhanging sand to make a safe cave ceiling, but I’ve been smothered several times by clicking in the wrong place by accident. I’m interest in learning the best methods for desert mining.
With featherfall4 one can (mostly) ignore the issue if working from above… (spaming torches as one advances will also trigger collapse).
From below, the important thing is to have a non-gravity full block over one's head (and extending back along one's line of retreat).
Placing torces on the floor under one's feet etc will also break falling sand/gravel (but can be dangerous if there is a lava pocket above….)
The safest way to work from beneath is to have a solid block overhead, a line of solid blocks immediately in front of one (slime by preference for ease of removal), and cover the rest of the area under the hanging sand with torches (other blocks will work but torches are cheap, easy to remove, and likely to be carried) before triggering the collapse.
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WARNING: I have an extemely "grindy" playstyle; YMMV — if this doesn't seem fun to you, mine what you can from it & bin the rest.
Use trapdoors to line the ceiling you wish to dig out. They can be opened and closed, giving you access to the blocks behind them, and if you place them in the lower configuration (opening upwards instead of downwards) then falling sand probably just drops as sand items instead of landing on the trapdoor as a block. "Dry" trapdoors also act as 1.12 trapdoors, not automatically waterlogging, so if you accidentally broke into a water lake, river, or ocean the water would not spill down into your cavehole. I don't think trapdoors burn, either, so you could use them to hold back spilled/deliberately-placed lava.
An alternative to the trapdoors is fences or walls. You could replace/cover the floor with fenceposts and cover the fences with carpets so you never fall through the gaps. The carpets would still be vulnerable to flowing liquid, but any sand that fell would just break on the carpet instead of potentially suffocating you. If you put them in the ceiling, you can mine the blocks above them and it will prevent the sand and liquids from falling into the cavehole.