40 MEXICAN RESOURCES. 



MINING AND MILLING. 



1st, Can ore-redncing be profitably carried on in this Republic so as to obtain 

 through it an income? If so, to what extent ? 



2d, Which is the part of the country most suitable for reducing silver and gold 

 ores? 



■^(\, Which of the known mining districts or zones offers for the future the best 

 mining prospects, or best probabilities to the industry of reducing ores ? 



In answer to these questions, Sefior Miguel Rul, a leading mining engineer of 

 Guanajuato, replies in substance through the columns of "The Two Republics " (an 

 American paper published in Mexico), as follows : — 



(i) "The income will be variable, — in one year, perhaps, enormous, but in another 

 small. It is advisable to erect reduction-works, especially for any one mine, but, 

 where transportation is low, better to make one establishment suffice for a large 

 group of mines. 



" My answer is therefore divided in two parts : Firstly, the business of reducing 

 ores does not offer probabilities enough of yielding a lasting or perpetual income, as 

 is the case, for instance, with a farm or a house ; but, secondly, said business, like all 

 others not consisting only in landed property, may render in good epochs large 

 profits, with which the capital laid out may be reimbursed." 



(2) Guanajuato he considers the place at which reduction is best carried on. 



(3) " As regards the third question, I believe, that, in our times, the most suitable 

 places of all the ones actually worked, to establish such a kind of business, should 

 be the environs of Pachuca and Mazapil (where I am not interested at all), those of 

 Salvatierra (which would favor my Guanajuato business), and, towards the south, 

 some places well fitted to reduce ores from the growing mining districts of Guerrero, 

 Morelos, and Oaxaca. With respect to future centres, of mining districts scarcely 

 worked, Chihuahua, Sonora, and Durango may be at once pointed out as the most 

 preferable ones." 



Sefior Rul's description of the method of treating silver ores most used in Mexico 

 is so valuable, that we herewith reproduce it. The "Patio System " originated in 

 Mexico, and its use is peculiar to the country. 



Granceo {crushing). — The first operation to which ores are submitted in order to 

 reduce them consists in their being ground into small lumps in mills, called Chilenos 

 (Chilians), substantially consisting of a large vertical iron or stone wheel pierced at 

 its centre by a horizontal shaft, to which mules are attached to furnish motive- 

 power. The ground upon which the wheel operates is a circle om 49 wide, formed 

 by iron pieces of the same material and thickness as the wheel-tire. Between this 

 circle and the vertical shaft there is a sieve, in the shape of a truncate cone, into 

 which lumps are shovelled, falling afterwards into a reservoir placed underneath 

 the mill. 



The crushed ores are taken to the hoppers, and thence* to the grinding mills, or 

 arrastres, where they are to be ground, or reduced to a very fine mud, — an operation 

 upon which depends the quantity of silver and gold obtained. The locality where 

 the a7'7-astres are situated is called the Galera. 



The arrastre is a circle 3m 50 diameter, constructed with flags inserted into the 

 ground, the interstices between them filled up with pebble, and then with fine sand 



