During the Spanish dominion little was done in the way of mining. Shortly after the Revolution, when it was believed that the South American countries, enjoying the advantage of "freedom," would go ahead, considerable interest was taken in Argentine mines, and Sir Francis Head made an adventurous journey across the Pampas and visited the gold-mines of San Luis and the silver-mines of Uspallata in the interests of the Rio Plata Mining Association, which had been formed in 1824. The Argentine Government did not deal honestly with the company in the matter of concessions, and Head came to the conclusion that there was no probability of obtaining satisfactory results by the importation of Cornish miners. The sum of £60,000 had been spent without any return, and Head's relations with his employers became strained.[123] The unfortunate company collapsed, and this was also the fate of the Famatina Mines, another English company formed at the same time, whose German manager was shot by the ferocious Quiroga and its capital of 1,000,000 dollars lost. Under Rosas, of course, mining and all other enterprise languished, but the belief in Argentina's mineral wealth continued, and from time to time attempts were made to develop it. A report published in the sixties states: "Extensive tracts of country are also highly auriferous, and gold-dust makes a considerable figure in the exports of Jujuy. The sierra of Cordova possesses silver, copper, lead, tin, zinc, and iron mines, besides a number of quarries of splendid marbles; and the same may be said of several of the provinces we have named. Petroleum, equal in quality to that of Pennsylvania, has been lately discovered, and, if our information be not altogether inaccurate, there is every reason to believe it will soon become valuable as a source of revenue and national wealth. Little has as yet been done to develop the mineral affluence of the Republic; but it is hoped effective efforts will shortly be made to work some of its already celebrated mines, as well as many more which diligent 'prospecting' would certainly reveal to the knowledge of mankind." In 1873 the export of metals of gold and copper amounted to 320,000 dollars gold. Progress was probably slow, but it has made considerable positive advance, for the recent average of gold exports alone has been about 382,000 dollars gold. Copper has, of late, remained stationary. Salt is produced in considerable quantities, chiefly in the south of the Province of Buenos Aires, and for a time petroleum borings in several parts of the Andes excited great hopes. Some trains were run by petroleum; but, unfortunately, the yield dwindled, and no fresh discoveries in satisfactory quantities have been made.