Mining Intelligence and News
Mexico

Bolanitos Mine

Click for more information

Categories

Overview

Mine TypeUnderground
StatusActive
Commodities
  • Silver
  • Gold
Mining Method
  • Cut & Fill
  • Longhole open stoping
Backfill type ... Lock
Production Start... Lock
Mine Life... Lock
SnapshotBolanitos mine is an Underground gold mine with exploration upside and nearby acquisition opportunities to provide future growth.

Currently, Endeavour is mining three orebodies at Bolañitos: Lucero, La Luz and San Miguel.

Owners

SourceSource
CompanyInterestOwnership
Endeavour Silver Corp. 100 % Indirect
Endeavour Silver Corp. controls the Bolanitos Project through its 100% owned subsidiary, Minera Bolañitos SA. de CV.

Contractors

Lock

- subscription is required.

Deposit type

  • Vein / narrow vein
  • Epithermal

Summary:

Local Geology
Epithermal systems form near the surface, usually in association with hot springs, and to depths on the order of a few hundred meters. Hydrothermal processes are driven by remnant heat from volcanic activity. Circulating thermal waters rising through fissures eventually reach a level where the hydrostatic pressure is low enough to allow boiling to occur. This can limit the vertical extent of the mineralization, as the boiling and deposition of minerals is confined to a relatively narrow range of thermal and hydrostatic conditions. In many cases, however, repeated healing and reopening of host structures can occur, imparting cyclical vertical movement of the boiling zone and resulting in mineralization that spans a much broader range of elevation.

Local Geology Of the geological formations associated with the Guanajuato district only the Esperanza and La Luz Formations occur in the Bolañitos mine area with mineralization residing primarily within the La Luz Formation. Mineralization is known to dissipate at the contact with the Esperanza Formation.

The vein dips from 35° to 55º to the southwest with measured displacement of around 1,200m near the Las Torres mine and 1,700 m near La Valenciana mine. The most productive veins at Bolañitos strike parallel to the Veta Madre system.

Bolañitos mineralization is directly related to faulting. Mineralization occurs as open-space fillings in fracture zones or impregnations in locally porous wall rock. Veins which formed in relatively open spaces are the main targets for mining.

There are 21 veins within the Bolañitos mine area that are included in the mineral resource estimate. These mineralized veins are known to occur from an elevation of 2300 m down to an elevation of 1900 m.

Deposit Type
The Guanajuato silver-gold district is characterized by classic, high grade silver-gold, epithermal vein deposits with low sulfidation mineralization and adularia-sericite alteration. The Guanajuato veins are typical of most epithermal silver-gold vein deposits in Mexico with respect to the volcanic or sedimentary host rocks and the paragenesis and tenor of mineralization.

Epithermal systems form near the surface, usually in association with hot springs, and to depths on the order of a few hundred meters. Hydrothermal processes are driven by remnant heat from volcanic activity. Circulating thermal waters rising through fissures eventually reach a level where the hydrostatic pressure is low enough to allow boiling to occur. This can limit the vertical extent of the mineralization, as the boiling and deposition of minerals is confined to a relatively narrow range of thermal and hydrostatic conditions. In many cases, however, repeated healing and reopening of host structures can occur, imparting cyclical vertical movement of the boiling zone and resulting in mineralization that spans a much broader range of elevation.

Low-sulfidation epithermal veins in Mexico typically have a well-defined, sub-horizontal ore horizon about 300 m to 500 m in vertical extent, where high grade ore shoots have been deposited by boiling hydrothermal fluids. The minimum and maximum elevations of the mineralized horizons at the Bolañitos mine have not yet been established precisely, but historic and current production spans an elevation range from 1900 to 2300 m.

Mineralization
Mineralized veins at Bolañitos consist of the classic banded and brecciated epithermal variety. Silver occurs primarily in dark sulfide-rich bands within the veins, with little mineralization within the wall rocks. The major metallic minerals reported include pyrite, argentite, electrum and ruby silver, as well as some galena and sphalerite, generally deeper in the veins. Mineralization is generally associated with phyllic (sericite) and silicification alteration which forms haloes around the mineralizing structures. The vein textures are attributed to the brittle fracturing-healing cycle of the fault-hosted veins during and/or after faulting.

Economic concentrations of precious metals are present in “shoots” distributed vertically and laterally between non-mineralized segments of the veins. Overall, the style of mineralization is pinch-and-swell with some flexures resulting in closures and others generating wide sigmoidal breccia zones.

The silver-rich veins of Bolañitos contain quartz, adularia, pyrite, acanthite, naumannite, arsenopyrite and native gold. Native silver is widespread in small amounts. Much of the native silver is assumed to be supergene. Silver sulfosalts (pyrargyrite and polybasite) are commonly found at depth.

Reserves

Lock

- subscription is required.

Mining Methods

Lock

- subscription is required.

Comminution

Crushers and Mills

Lock

- subscription is required.

Processing

Lock

- subscription is required.

Production

CommodityProductUnits202320222021202020192018201720162015
Silver Metal in concentrate koz  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe6259769341,0531,450
Gold Metal in concentrate koz  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe1521273124
Silver Equivalent Payable metal koz  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe1,8072,5602,9523,357
Silver Payable metal koz  ....  Subscribe  ....  Subscribe  ....  Subscribe6049478971,0111,390
Gold Payable metal koz  ....  Subscribe  ....  Subscribe  ....  Subscribe1421263023
^ Guidance / Forecast.

Operational metrics

Metrics202320222021202020192018201720162015
Daily processing rate  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe868 t1,203 t1,224 t1,391 t
Daily processing capacity  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe1,600 t1,600 t1,600 t1,600 t1,600 t
Waste  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe
Tonnes processed  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe316,708 t439,005 t446,924 t507,704 t455,226 t
Ore tonnes mined  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe
^ Guidance / Forecast.

Production Costs

CommodityUnits202220212020201920182017
Total cash costs Silver USD  ....  Subscribe  ....  Subscribe  ....  Subscribe 12.9 / oz   10.5 / oz   10.3 / oz  
Total cash costs Gold USD  ....  Subscribe  ....  Subscribe  ....  Subscribe 1,124 / oz   849 / oz   767 / oz  
Total cash costs Silver USD  ....  Subscribe  ....  Subscribe  ....  Subscribe 6.72 / oz **   2.14 / oz **   -4 / oz **  
All-in sustaining costs (AISC) Silver USD  ....  Subscribe  ....  Subscribe  ....  Subscribe 25.1 / oz **   9 / oz **   1.62 / oz **  
** Net of By-Product.

Operating Costs

Currency2022202120202019201820172016
Direct operating costs ($/t milled) USD 94.4  79.4  70.1  77.3  64.2  67.7  57.1  

Financials

Units2023202220212020201920182017
Capital expenditures (planned) M USD  ....  Subscribe
Sustaining costs M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe 7.8   3.5   1.6  
Capital expenditures M USD  ....  Subscribe
Revenue M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe 32.4   39.8   48.4  
Pre-tax Income M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe 2.8   12.5   17.5  
After-tax Income M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe 4.1   11.5   15  

Heavy Mobile Equipment

Lock

- subscription is required.

Personnel

Mine Management

Job TitleNamePhoneProfileRef. Date
....................... Subscription required ....................... Subscription required ........... Subscription required Subscription required Aug 1, 2023
....................... Subscription required ....................... Subscription required Subscription required Jul 28, 2023
....................... Subscription required ....................... Subscription required Subscription required Jul 28, 2023

EmployeesContractorsTotal WorkforceYear
...... Subscription required ...... Subscription required ...... Subscription required 2022
...... Subscription required ...... Subscription required ...... Subscription required 2021
...... Subscription required ...... Subscription required ...... Subscription required 2020
...... Subscription required ...... Subscription required ...... Subscription required 2019
...... Subscription required ...... Subscription required ...... Subscription required 2018
...... Subscription required ...... Subscription required ...... Subscription required 2017
...... Subscription required ...... Subscription required ...... Subscription required 2016
...... Subscription required ...... Subscription required ...... Subscription required 2015

Aerial view:

Lock

- subscription is required.