Castrol Molub-Alloy™ OG 936 SF Heavy (previously called Molub-Alloy 936 SF Heavy) is an open gear lubricant developed specifically for use on heavy duty equipment in mining and industrial service. Molub-Alloy OG 936 SF Heavy is compounded to give maximum protection to gears and slides on large draglines and shovels while minimising potential pollutants to the environment. A proprietary blend of Molub-Alloy lubricating solids is included to promote anti-wear and load carrying properties. These lubricating solids work synergistically with chemical anti-wear and Extreme Pressure (EP) additives to reduce contact temperatures while providing excellent anti-weld protection under extreme pressure and shock loading. The structural integrity and strength of the lubricating film is particularly valuable in the critical process of seating new gears because of the natural occurrence of high spots (asperities) in newly machined surfaces. The lubricating film must separate the mating surfaces sufficiently to cushion the effect of the impact of asperities, and therefore minimise initial pitting which could lead to progressive and destructive pitting later. A highly refined, viscous, paraffinic petroleum derivative is the foundation of a blended base fluid with excellent natural chemical and thermal stability. Molub-Alloy OG 936 SF Heavy is compounded to flow readily in the film-forming process; yet it resists "squeeze-out" and clings tenaciously even to gear teeth in vertical orientation. Rust and oxidation inhibitors are included in the formulation to protect the equipment and the lubricating film against the elements in severe climates.