[nicephotog]

{ edited I misread that.....

That's 20 tons P/hour, and presuming a standard ton (all similar imperial , SAE or ?Soviet) not short ton or long ton or tonne , it would be around or less than one cubic metre 1x1x1 and twenty volumes of this P/hour.

"Possible" with a pick and enough air for the miner but mainly space to swing in without worrying they would kill anyone else !
This last point (space to swing) apart a vein good enough to get that much from (with a double ended pick and a wide enough path inside a vein you can swing back on the other wall side)  is probably the biggest factor.
But of essence, what does "mined" mean, when is that point achieved e.g. at the surface,? in the truck?
Note: a 44 gallon drum of water weighs 213kg - forklift license info

What do you actually want with it?
Are you trying to incite coal mining Olympics as an event?

Remains just possible(since the assessing my reading error)

[Petrochemicals]

That's 20 tons P/hour, and presuming a standard ton (all similar imperial , SAE or ?Soviet) not short ton or long ton or tonne , it would be around or less than one cubic metre 1x1x1 and twenty volumes of this P/hour.

Half a metre square. Ie 0.5x1x1. Favourable coal all you would really need to do would be to stick a pick behind it.

Coal is a broad term, jade is in fact coal but I would think it was harder to mine.

[Bored chemist]

Coal is a broad term, jade is in fact coal

I presume you mean jet.
I can see why you might identify with jade; it's tough to get through, green and dense.

[nicephotog]

[Half a metre square. Ie 0.5x1x1. Favourable coal all you would really need to do would be to stick a pick behind it.

One problem there is Soviet diet in the 1930s , it apparently was short of meat and mainly was for some mostly Corn.
How much rice was ever their diet is neither understood but it wasn't ever traditional protein intake at any one rate.
More than that the Five ears of corn law would have been heavily serviced at that time so a wonder about miners diets.