On April 28, 1956, an oil shale refinery with an annual output of 1 million metric tons of crude oil was approved to be built in Maoming, and was included among the 156 national key projects during China's First Five-Year Plan (1953-57) period.

Maoming, a city founded in 1959, gradually became a well-known "oil city in southern China".

The refinery was officially put into production in 1961, and extracted a total of 102 million tons of oil shale until 1992 when the factory was suspended and converted to national energy reserves. It produced 2.92 million tons of shale oil during the period, which is 24 times the national crude oil output in 1949.

In 2013, Maoming decided to shut down all the polluting enterprises in the mining area and carry out environmental remediation and ecological restoration.

The city channeled 160 million cubic meters of water into the pit lake through the Gaozhou Reservoir irrigation channels, and connected the lake with Xiaodong River to form a set of running water systems. The water quality of the pit lake was completely changed, and also helped irrigate over 8,800-mu (586-hectare) of surrounding farmland.

The beautiful ecological park is now called the Maoming Open-pit Mine Ecological Park. The park was named a "National Mine Park" in 2017, and has become one of the most beautiful sites in the city.

The beautiful and green Maoming Open-pit Mine Ecological Park. [Photo/WeChat account: maofabu]