If this coin loose the same value like from july till now, miners will stop working on it.
I doubt that. I have mined digibyte few months. The difficullty and so required amount of electricity usually stabilize. So if you mine 100 DGB per day and price falls for 50%, after difficulty adjustment you would mine 200DGB which are worth same as before if you convert them in FIAT.
The only problem I see in price falling is security of the network. Because there is less hash power.