A $50 billion gold-industry deals spree is extending into its third year, even as a surging bullion price makes sealing transactions and valuing mines more difficult.

Gold has regained its luster as investors seek havens from volatile markets and weak interest rates. While the metal is up about a quarter this year, the value of mergers and acquisitions has soared. The average paid in 133 transactions in the three months to June was $64 an ounce of gold equivalent in the ground, up from $36 in the first quarter of 2016, as buyers factor in better long-term price expectations, according to Bloomberg Intelligence.