Mining equipment maker Joy Global (JOY) reported first-quarter earnings above estimates early Wednesday, but equipment bookings fell as coal production slowed on cheap natural gas. Joy Global shares rose more than 5% in the stock market today despite the drop in bookings and a cautious outlook. Caterpillar (CAT) shares rose nearly 2%. The company said earnings were flat at $1.33 per share, but topped analyst estimates by 19 cents. Revenue rose 1%