19,300 mi2 (50,000-km2) is to the north and east of Shell's TPC. Americas Argentina In June 2013, the US Energy Information Administration estimated that Argentina held 802 trillion cubic feet of recoverable shale gas reserves, the third largest in the world. Large reserves of tight oil and gas were in the Vaca Muerta formation. In 2014, three-quarters of the shale gas and oil concessions in the country were held by the Argentinian company YPF (nationalised in 2012) which committed to develop the Vaca Muerta field with US company Chevron Corporation. However, in spite of a hydrocarbons law favourable to exploring and developing companies and passed by the Argentine Senate in 2014, the Financial Times noted that "Some analysts doubt whether many companies will follow Chevron until Argentine's erratic president Cristina Fernandez, leaves power in 2015." Canada Recent shale gas discoveries have caused a sharp increase in estimated recoverable natural gas in Canada. The nation has a number of prospective shale gas targets in various stages of exploration and exploitation in British Columbia, Alberta, Saskatchewan, Ontario, Quebec, New Brunswick and Nova Scotia. One major area of exploration in Canada is north of Fort Nelson, in north east British Columbia. Encana and EOG Resources are developing the area known as Horn River due to its high yield shale deposits. A number of these well sites are serviced by Alberta fracturing companies, many of which started out as a one-person operation with the purchase of a cement truck. This rapid expansion of shale gas in Canada is not without controversy. On 8 March 2011, the Quebec provincial government effectively declared a temporary moratorium on the use of chemical fracturing during shale gas drilling pending a stricter full environment assessment audit. Acting under recommendations from a provincial environmental assessment board, Quebec Minister of Environment Pierre Arcand stated that "We are committed to making sure that it is done properly or it won’t be done at all," The assessment board cites the chief concern of groundwater contamination with respect to the St. Lawrence valley, and recommended the audit in order to fully inform and involve communities and the public of the risks involved in shale gas exploitation in Quebec. Mexico Mexico drilled its first shale gas well in 2011, in the Burgos Basin of northern Mexico, in the equivalent of the Eagle Ford Formation of the US. But as of February 2013, there have been