The normal route up Aconcagua (13,000 ft climbing) has been done in under 12 hours on foot. Kilimanjaro (~14,100 ft climbing) has been done in under 9 hours on foot.
If you want to remove the single ascent requirement you have something like Hardrock you have more than 33,000 ft climbing in less than 23 hours on foot. Ouray 100 with over 41k of climbing in 30 hours (probably could get that down to 24 hours if someone like Kilian ran it) I would say that full Aconcagua in a day would be more than possible for the right athlete.
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If you want to remove the single ascent requirement you have something like Hardrock you have more than 33,000 ft climbing in less than 23 hours on foot. Ouray 100 with over 41k of climbing in 30 hours (probably could get that down to 24 hours if someone like Kilian ran it) I would say that full Aconcagua in a day would be more than possible for the right athlete.
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