Some languages have only a single hushing sibilant and no hissing sibilant. Middle Vietnamese is normally reconstructed with two sibilant fricatives, both hushing (one retroflex, one alveolo-palatal). Somewhat more common are languages with three sibilant types, including one hissing and two hushing. Many languages, such as English, have two sibilant types, one hissing and one hushing. The Russian foreign minister, Sergey Lavrov, accused German authorities of hushing up the case. They were used to supply water for hushing mineral deposits, washing ore and powering mills. One of the earliest techniques for extracting the ore is called "hushing". There was a limestone hushing operation at Shedden Clough in the 17th century.