Please tell me what type of bike this is? http://www.njuskalo.hr/image-bigger/mtb-bicikli/rog-kanin-dosta-novih-dijelova-slika-2716844.jpg

Weight...heavy ca. 17 kilos

Mountain?
It seems to be what some call a BSO: Bike Shaped Object. (This is a derogative term).

It indeed mimics a Mountain Bike, a Dual Suspension Mountain Bike, but as you state it is really heavy, it means it is made of steel, and not necessarily good grade steel.

From what the picture shows, it also appears to be fitted with low level components, but the headset appears to be 1 1/4 inch and fitted with a good RST fork with threadless steerer tube and stem. The rear suspension looks really cheap.