Growth in yearly mining production slowed to 1.7% in April from 15.4% in March as growth in 9 of the 12 mineral categories surveyed slowed on a yearly basis, Nedbank said in a statement on Thursday. On a seasonally adjusted basis, mining production decreased by 1.6% month-on-month in April, but was up 5.5% quarter-on-quarter for the three months to April 30.