南非统计局：南非4月黄金产量同比下降2.5%。

Group 1 - The core point of the article is that South Africa's gold production in April decreased by 2.5% year-on-year [1] Group 2 - The decline in gold production indicates potential challenges for the mining industry in South Africa [1] - This reduction may impact the overall economic performance of the country, given the significance of gold mining in South Africa's economy [1] - The decrease in production could lead to a reassessment of investment strategies within the mining sector [1]