pay dirt
noun
mass noun
1- Mining, chiefly N. Amer. ground containing ore in sufficient quantity to be profitably extracted【矿】〈主北美〉可采矿石区。
1.1
- informal profit; reward〈非正式〉利益; 报偿：
the gig pays three hundred bucks a week - looks like I just hit pay dirt.
这个活每星期可挣300美元, 看来我刚刚发现生财之道。