Complex sentence: Prospector's Delite is best known for producing the 2003 Horse of the Year, Mineshaft who earned over $2,000,000 and won the Jockey Club Gold Cup.
Split into simpler sentences: Prospector's Delite is best known for producing the 2003 Horse of the Year, Mineshaft. Mineshaft earned over $2,000,000 and won the Jockey Club Gold Cup.