Meanwhile, China, Australia's largest customer of natural sources, announced Monday a 50 basis points hike in the reserve requirement to 17% for the nation's biggest banks effective May 10. This move will lead to lower bank lending to industries and hence a lower commodity demand in China. This will likely impact China's imports and could dent earnings of the mining giants. These events compound the problems of BHP and Rio, which had anticipated production disruptions at a few of their mines during their respective March-quarterly reviews. For the March quarter, BHP registered year-over-year growth rates of 22% and 9% for crude oil and natural gas, respectively. Production of lead, zinc, silver and nickel zoomed by 29%, 18%, 32% and 8%, respectively, while production declines for copper and uranium were 19% and 90%, respectively. Production of iron ore increased by 11%, but was below analyst expectations. In fact, the company missed analyst output expectations in petroleum, copper and coal, while transcending expectations in manganese and nickel. Management cited weather and long wall changeovers for coal, lower grade for copper, and maintenance for petroleum as the reasons impacting production. For the June quarter, the company anticipates output disruption for petroleum at Atlantis, for copper and uranium at Olympic Dam, and for coal at Hay point. Management is confident that the recently implemented iron ore pricing based on spot prices is permanent. However, the China Iron & Steel Association is likely pressure the three mining giants following a 14% quarter-over-quarter drop in the country's steelmakers' profits during the March quarter. Rio Tinto also missed analyst output expectations on iron ore, copper, aluminum and coal. In the March quarter's operation review , the company announced a year-over-year decline in copper and uranium output by 16% and 20%, respectively. In contrast, production of gold, bauxite, and hard coking coal increased 12%, 58%, and 35%, respectively during the same quarter. As per TheStreet's Analyst ratings guide, Rio has seven buy, three hold, and no sell ratings. BHP has seven buy, two hold, and no sell ratings.