From the establishment of the state until the Porfirio Díaz period, the economy, especially the mining sector was erratic. In the late 1880s, a number of modern inventions, such as the telegraph, telephone and railroad helped the Hidalgo economy. It also brought in another wave of foreign investment in the mining industry. By the mid-1900s, much of the mining production in Pachuca and Real del Monte was controlled by U.S. based interests such as the United States Mining Smelting and Refining Company. Pulque haciendas, primarily selling to nearby Mexico City, were prosperous in the late 19th and early 20th centuries. The prosperity of the state was best seen in the capital of Pachuca with the construction of many civic structures, but many rural areas were still quite impoverished. This situation would make the state favor the oncoming Mexican Revolution.