Heinzmann came home first in the LW6/8 category of the men's giant slalom, adding to golds he has already won in the downhill and super-G.
Germany's Martin Braxenthaler and Ferd Schonfelder won the LW10 and LW3,5-7,9 categories respectively.
Harald Eder led an Austrian clean sweep in the LW11 category, while Australia's Michael Milton took the honours in the LW2 category, and New Zealand's Steven Bayley was first home in the LW4s.
The men's cross country relay was won by Russia in the tightest of finishes ahead of the USA.
The Russians came home in 45 minutes 49.1 secs, just 1.6s ahead of the Americans with Norway a distant third.
Norway took gold ahead of Russia and Finland in the women's race.