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The Guanajuato mint

Guanajuato mint

The city of Guanajuato is the capital of the state of Guanajuato. Located 220 miles northwest of Mexico City in a rich mining area, this mint is reported to have been established as a rebel mint by Hidalgo in 1810. The first known coinage of this mint, however, is under Spanish Colonial rule in 1812. The first Republican 8 Reales were minted in 1824 and bore the Profile or Hook-neck Eagle design. In 1830 Guanajuato became the first mint in Mexico to produce its 8 Reales from hubs. This resulted in a great improvement in the quality of the coinage. Eight Reales coinage was interrupt ed three times during this mint’s long run. The first interruption was 1863-1867 during the Maximilian era. The government of Maximilian occupied the mint from 8 December 1863 to 26 January, 1867 and struck Maximilian Pesos dated 1866 with the Go mint mark. The second interruption was in 1869, a year for which no Guanajuato coinage is known. The third interruption was for the issue of the Balance Scale Peso series in 1871-1873. Guanajuato was one of only four mints to coin 8 Reale until the series ended in 1897.

Shortly after Mexico gained its independence, the mint of Guanajuato was leased to the Anglo Mexican Mint Association. This British firm was closely related to the Anglo Mexican Mining Association, which began serious mining operations in the region in the 1820s. They acquired the mint as a means of refining and minting silver from their mining operations in the region. It became immediately apparent to the Anglo Mexican Mint Association that the facilities in Guanajuato were in dire need of modernization. It is important to note that both the mint and the mining operations in this region were controlled by English firms. For this reason, the natural choice for purchasing minting machinery was through Matthew Boulton and the Soho Mint. The task of engraving the dies was given to William Wyon.

A series of major engraving errors occurred annually across the four smallest denominations of coins in Guanajuato.

Mínt owners or lessees and their tenures

from to  
October 1824    
l June 1825 24 April 1842 Cia. Anglo-Mexicana (Manning & Marshall), by a contract dated 31 May 1825
24 April 1842 31 March 1874 Cia. Mexicana de Casa de Moneda (Manning & Marshall), by a contract dated 13 December 1841
1 April 1874 30 June 1876 Government of the Republic of Mexico
27 May 1876 30 June 1895 Cia. Guanajuatense Zacatecana (formerly Cia. Anglo-Mexicana)
1 July 1895 1 July l 900 Government of the Republic of Mexico


In March 1853 the provisional government of Manuel M. Lombardini leased the mints of Guanajuato and Zacatecas to Jecker, Torre y Compañía. However, in May 1853 the new government of Santa Anna rescinded this contract without it being executed.

Assayers and their tenures (as evidence by coinage)

Pradeau in his monumental work Historia Numismatica de Mexico 1823-1950 gives and impressive list of assayers for Guanajuato and their tenures. The problem is that in only a few cases do the initials and tenures match up with the coins. Pradeau points out that the initials represent two assayers, but this is clearly at odds with one of the early initials that match exactly the assayer and bis tenure. We believe that Pradeau was partially right and that on the later issues (1878-1897) the initial do correspond to two assayers. Probably the volume at Guanajuato became so great that two primary assayers were needed. Based on Pradeau's list we have attempted to identify, where possible, the assayer's initials that appear on the coins.

Initial Name Began on Left office on
 JM José Amonio Mucharraz 1824(since 1821 under Spanish Colonial Rule  
IJ José Mariano Jimenez 1825 1826
MJ unknown 1826 1833
MR unknown 1827 1828
JM unknown 1833  
PJ unknown 1834 1842
PM Patrick Murphy 1842 1848
PF unknown 1848 1861
YE lnocencio Espinoza 1862 1863
YF Yldefonso Flores 1862 1863
    1867 1870
FR Faustino Ramírez 1870 1878
SM unknown (possibly Francisco Sardaneta and Roman Mendoza) 1878 1879
SB unknown (possibly Francisco Sardaneta and Aguslin Barbachano orJacobo Blanco) 1880 1883
BR unknown (possibly Jacobo Blanco and Cario Romero) 1883 1884
RR unknown (possibly Carlos Romero and Carlos Rodriguez Rey) 1884 1890
RS Rosendo Sandoval (possibly with Carlos Romero) 1891 1900