The entrance choke led into Velika Dvorana - more of a huge passage than a chamber. Severozahodni Rov is the only significant side passage and is located behind a house-sized boulder.

A mud traverse and bridge led to walking passage, ending at the top of a climb, descending to a platform above another drop. A difficult climb up flowstone to the left proved to be the way on. The passage continued, lowering to a descending tube which led to another difficult climb down into a mud-floored chamber, with a 'doorway' into a smaller chamber. At the far side of this was a mud-lined double shaft, normally a sump! Descent was made down a 5m pitch into knee-deep mud! The sump, now, was merely a small pool.

A descending narrow rift appeared to be the way on, initially constricted, then continuing down to the left. Continuation was too tight and there was no draught here. The chamber at the top of the rift was named Sifon Dvorana.

On the way out, a definite draught was felt in Blatni Rov - the passage leading to the sump. When this was reported to France later, he claimed that there hadn't been a draught reported here before and that this could indicate a link between Mackovica and Logarcek Jama with a prospect of a 3Km through trip!