Study Notes on the Spanish Silver Trade Routes by Kenneth Maxwell

Historical Context of Discovery (1545):
- A decade after the conquest of the Inca Empire (1532-34), Diego Gualpa, an indigenous prospector, discovered the richest silver deposit in the world in the Andes at a height of 4,800 meters (15,750 feet).
Cerro Rico:
- Termed “Cerro Rico” (“Rich Mountain”) by Spaniards; the mining boomtown that emerged quickly grew into one of the largest and highest cities worldwide.
Recognition and Naming:
- By 1561, King Philip II of Spain decreed that it be known as the “Villa Imperial de Potosí.”

Wealth Source:
- Peru had established a reputation for abundant treasures, highlighted by the ransom paid in gold and silver for the Inca emperor Atahualpa and captured by Francisco Pizarro at Cajamarca (around a million pesos).
Silver Contribution:
- Potosí’s silver output accounted for 60% of the world’s silver by the end of the 16th century, producing nearly 20% of all known silver over 265 years (1545-1810).
Statements of Wealth:
- Charles V referred to Potosí as “the Treasury of the World” due to its significant contribution to Spain’s wealth.

International Trade Routes:
- Potosí’s silver was crucial in breaking Eurasia’s bullion famine post-1550.
- Silver flows spanned from South America to Spain, reaching the Ottoman and Safavid Empires and Mughal India, with pathways extending across the Pacific to Manila.
Global Currency Creation:
- Established the “pieces of eight” (with a mark “P” for the Potosi Mint, initiated by Viceroy Francisco Alvarez de Toledo in 1574).

Cerro Rico Mining:
- The richest silver and tin veins in the world.
- Veins average about a meter wide and extend steeply into the mountain.
Depth of Mines:
- By reaching the water table at depths of 400-500 meters.
**Processing Techniques:
- Initially involved smelting by crushing silver ore using stamp mills powered by mules/water wheels and smelting ores in blast furnaces using wood and charcoal.
- Six thousand furnaces (guayra) utilized, connected by bellows.
Types of Furnaces:
- Silver-gold alloy processing utilized cupellation furnaces lined with bone ash to absorb the oxidized lead, permitting the extraction of pure silver and gold alloys via nitric acid methods imported from Germany.

Process Overview:
- Crushed ore mixed with water, mercury, salt, and impure copper sulfate; spread over a patio for amalgamation.
Recovery Techniques:
- The muddy mixture was washed, and amalgams pressed into bars were heated to vaporize mercury, with a quarter lost in the process.

Haciendas de Minas:
- Mines incorporated processing mills, residences for mine owners and workers, and essential facilities such as stables and chapels.
Water Supply Systems:
- Reservoir construction in Kari mountain by Francisco de Toledo to address unpredictable rainfall at Potosí.
Worker Conditions and Labor Supply:
- Indigenous populations provided the majority of labor, subjected to the Mita system, which required them to work under perilous conditions in the mines and processing facilities.
- By 1658, there were 120 processing mills characterized by complex machinery.

Source and Utilization:
- Initially imported from Almadén, Spain, until discovering a rich mercury mine in Huancavelica (1570).
- The mine became the basis for tax on precious metals (the quinto).
Labor Conditions:
- Work was devastating, with many indigenous miners suffering health consequences due to mercury exposure.

Political Actions and Reforms:
- As viceroy, Toledo sought to optimize silver production, abolishing the chaotic early systems of Spanish rule by enforcing the Mita labor system and establishing long-term settlements.
Minting and Production Statistics:
- Potosí’s mint established a reliable process for stamping coins, with 444,000 lbs. of pure silver processed in Potosí reported in 1592.

Travel Logistics:
- Indigenous labor drafts required extensive travel for labor obligations impacting local populations.
Primitive Mining Techniques:
- Accessing silver veins involved arduous conditions; mines reached 750 feet depth by 1600.
Shipping Routes:
- Silver from Potosí moved primarily by llama and mule to coastal shipping ports, with challenging navigation through the Panama Isthmus.

Commodity Exchanges:
- Silver imported iron, textiles, and food required for sustaining mining activities; production demand led to agricultural stimulation in surrounding areas.
Interconnected Markets:
- Increased complexity in trade as Potosí’s growth created demand for goods beyond silver, implicating global commerce.

Trade Challenges:
- By the mid-17th century, Potosí faced declining economic conditions due to scandals and competition from other powers in Europe and Asia.
Continued Significance:
- Despite its decline, the silver from Potosí established a foundational role in complex transcontinental exchanges and economy.
Final Years of Influence:
- The establishment of global interconnections through Potosí silver paved pathways for future trade, but the legacy faced scrutiny as accountability issues arose in precious metal currency.

Andean Rebellion of 1780:
- Resistance emerged against the Mita system amidst economic stress, led by indigenous leaders with aspirations of reform and recognition.
Legacy of Potosí:
- By 1825, the abolition of Mita and growing national identities culminated in the establishment of Bolivia, highlighting the historical significance blanketed by struggles for independence and rights among indigenous populations.