Abstract <p>The southern flank deep structure of the Kuvalorog intrusion, located in the Kvinum–Kuvalorog nickel-bearing zone of the Sredinny Ridge (Kamchatka), was investigated. A volumetric density distribution model up to a depth of 5 km below sea level was developed using the density modeling method. Massive blocks with density similar to basitic rocks of the nickel-bearing plutonic Dukuk gabbro–peridotite complex were localised. These dense blocks formed two stages, which represented the chambers of a single magmatic system. The upper stage corresponded to the exposed part of the Kuvalorog intrusion, while the lower stage consisted of separate blocks located at depths ranging from 0 to 2 km. Massive blocks of both stages were connected by arc conductors of complex shape. Small basite bodies exposed southwest of the main intrusion could be considered apophyses of the conductors. The volume of hidden magma chambers of the lower stage were quantitatively estimated, and the theoretical amount of metals contained in them was assessed. The average nickel, copper, and cobalt contents in rocks of the nickel-bearing complex exceed crustal background values by 1.5–3 times. The largest resources (on the order of millions of tons) were found in the massive block in the vicinity of the interfluve of the Kikhchik and Pravaya Kikhchinskaya rivers. The nickel content was found to be 1.71; the copper content, 0.80; and the cobalt content, 0.51. The quantity of metallogenic resources present in the magma chambers of the lower stage was found to be the minimum possible.</p>