There does seem to be some doubt over his accomplishments. But in any case, decomposing bodies and coal aren't the same thing. Unlike the death camp sondercommando, Stakhanov didn't have to put the coal in the ground first. Stakhanov accomplishments didn't require burning the coal either. But if it had, he would find coal burns easier than corpses.
Coal mining is undoubtedly harder physical labour than the work of the Sonderkommandos. We also have some nice points of comparison between German coal miners and foreigners including Soviet POWs who were forced down German mines in WWII. Unsurprisingly, the Soviet POWs had a lower productivity than the German coal miners.
The productivity of the corpse removers and burners is only part of the process. If they're using mechanical scoops, it would make that end of the job much easier than if they had to do it by hand.
And in several places they used excavators. Your point?
The other end of the process is where the amazing feats of productivity occur--removing the bodies from the gas chambers and arranging them in the mass graves to achieve a density far greater than that of any other mass grave.
Very few other mass graves were as continually added to as the mass graves at the death camps.
It's extremely demanding physically but it also requires highly developed visual spatial skills and a degree of coordination between workers--a degree of coordination that would need to be developed with a staff that is comprised of people who have been on the job for no more than a couple of weeks.
I think a far better comparison is with landfill sites. The graves were filled continuously over a period of weeks and months, during which time decomposition as well as sheer physical pressure solved all the space problems perfectly well.
Belzec was closed at the end of 1942 to new 'business' because the graves were overflowing. There were still more than 150,000 Jews in Galicia to kill, though, which would have been an increase of 1/3 on the actual death toll. So the Nazis machine-gunned the remaining 150,000 Galician Jews into smaller mass graves right where they lived, leaving many dozens of mass graves dotted all over the eastern Galician countryside. That was in addition to the 78 mass graves they left dotted all over the western Galician countryside with many 10s of 1000s of bodies in them.
There is only one possible explanation as to why Belzec needed 21,000 cubic metres of grave space. Even Snakey managed to kill off nearly 280,000 victims into those graves, which would leave 150,000 supposedly unaccounted for since we know beyond a shadow of a doubt that 434,000 Jews were deported to Belzec.
We also know beyond a shadow of a doubt that more than half that number were deported westwards from eastern Galicia to Belzec and that the rest were deported eastwards from western Galicia and the Lublin area.
The day when someone tells me about a colony of Jews from Krakow somewhere to the east of Belzec, or a camp which held previously unaccounted for Jews from Lwow to the west of Belzec, is the day I might take denier gibberish slightly more seriously.
There is simply no explanation which can leave out the facts regarding where the victims came from and remain even vaguely honest or coherent. Yet in all the pseudomaths and amidst all the incredulity from the Dead Nazi PR Machine, we absolutely never hear about those basic, undeniable facts, which are utterly intrinsic to the history of Belzec and cannot be abstracted away with a handwave.
It's perfectly clear that the Belzec mass graves could accommodate all the victims allowing for decomposition
and the fact that the camp closed when the graves overflowed. None of the arm-twirling from the DNPRM changes that. But you're doubly screwed because in all of your handwaving you've neglected to account for the deportations and thus the identity of the victims. Not to mention the undeniable fact that Jews who according to the documented Nazi coverstory were supposed to be going east were actually going in utterly the wrong direction.
Your arguments are excruciatingly tedious, because they never bother to think things through several steps ahead. You just say one thing and leave the whole issue hanging in mid-air, then try to change the subject.