Globally, since 1940 till end 70s the production of coal by Ombilin declined, and shrank to only tens of thousands of tons per year. Sawahlunto also faced a decline in coal production indicative of the decline in population to only 13,561 inhabitants in the 1980. With the increased number of facilities, a change in management and the application of new technology, the mining industry increased again since the beginning of the 80s. Moreover, production continued to increase even exceeding 1 million tonnes per year in the late 90s. The population in Sawahlunto increased to 15,279 according to the Census in 1990. Even though the population growth rate is only 1.2%, it is still below the annual average population growth rate of Sumatera Barat which reached 1.62% and did not appear correlated with increased production of coal.