Mining grease composition and preparation method thereof

The invention provides a mining grease composition and a preparation method thereof. A thickening agent consists of products of reaction of 12-hydroxystearic acid, boric acid and sebacic acid with aqueous solutions of lithium hydroxide and calcium hydroxide; and an additive comprises an ethylene-propylene copolymer, an extreme pressure agent, an antirust agent and an antiwear agent. The preparation method comprises the following steps of: adding 12-hydroxystearic acid, sebacic acid and ethylene-propylene copolymer into base oil, mixing, heating to 60 to 90 DEG C, adding lithium hydroxide monohydrate containing boric acid and calcium hydroxide to carry out saponification and compounding for 1.5 to 2 hours; heating to 185 to 190 DEG C in a period of 2 hours, and keeping the temperature for 1.5 hours; and continuing to heat to 220 to 240 DEG C, naturally cooling to below 120 DEG C, adding the extreme pressure agent, the antirust agent and the antiwear agent and carrying out posttreatment to obtain the product needed. The grease has high high-load performance, so the wear is low under a high load (PD is more than 315kg).The grease also has highly improved water resistance and adhesive strength.