Why would you not use expanded metal to catch the coarse gold??? Most posters here myself included, are not likely familiar with brasilian carpets or imagem. As such you are not likley to get very much useful advice here. Why not use conventional miners carpet / moss?? Do you have previous sluice mining experience or are you new to the business and learning as you go?? Could be an expensive learning process if you dont have the basics.

miningman, thanks for reply , I am brasiliam , sorry if ortografic erros...
yes, here in Brasil and latin america in most place where brasilians work in dredges we do not use moss and expanded metal...
I personally beleave moss and spanded metal is more efficient...make a few years peoples introducing moss here in Brasil but the big dredges do not use...
at this moment I am partner in a 18" cutter drdge in Colombia , Cauca river , I dont know if is possible ask your email in this forum , I would like send pictures and videos for you have idea how big is our dredge ...

Suggest you get hold of some mining engineering text books... the older ones like Peele 1946 have all got sections on placer mining. Look especially at riffles and other methods of recovering coarse gold. Even a quick search on youtube for "gold riffles" will give you some ideas. Not much point in relying on mats to recover fine gold if you are not trapping the high value nuggets.