Ann: Regulatory Approval Granted for 90 Additional Drill Pads, page-5

The Carlin Mine is a significant gold mine located in Eureka County, Nevada, USA, specifically within the prolific Carlin Trend. It is widely recognized for giving its name to "Carlin-type" gold deposits, a unique and globally important class of sediment-hosted disseminated gold deposits.

Here's a breakdown of key aspects:

Location and Accessibility:

• The Carlin Mine is situated about 35 km (22 miles) north of the town of Carlin, Nevada.

  
  

• It's accessible by an asphalt-surfaced road extending northward from the town.

  
  

Ownership and Operation:

• The Carlin Mine complex is part of Nevada Gold Mines (NGM), a joint venture formed in 2019 between Barrick Gold (61.5% ownership) and Newmont Corporation (38.5% ownership).This joint venture combined the companies' significant assets across Nevada, creating the single largest gold-producing complex in the world.

  
  

Gold Production and Significance:

• The original Carlin Mine began production in 1965.

  
  

• The Carlin Trend itself is one of the world's richest gold mining districts, having produced nearly 100 million ounces of gold since the Carlin Mine opened.

• Nevada, largely due to the Carlin Trend, accounts for a substantial portion of U.S. gold production (73% in 2022) and a significant percentage of global production (3.5% in 2022).

• The Goldstrike mine, which adjoins Newmont's Carlin mine complex, is also on the Carlin Trend and has produced a massive amount of gold (44.4 million ounces by 2018 since Barrick acquired it in 1986).

  
  

Geological Characteristics (Carlin-Type Deposits):

• Host Rocks: Carlin-type gold deposits are primarily hosted in silty carbonate rocks, typically limestones with significant clay content. At the Carlin Mine specifically, the orebodies are mainly within the Siluro-Devonian Roberts Mountain Formation.

• "Invisible Gold": A defining characteristic is that the gold is exceptionally fine-grained and invisible to the naked eye, often microscopic (a few microns across).It's typically enclosed within arsenian pyrite (iron sulfide) and requires chemical analysis for detection.

  
  

• Associated Elements: These deposits are enriched in elements like arsenic, antimony, mercury, thallium, and barium, along with gold.

  
  

• Formation: The formation involves complex geological processes over millions of years, including tectonic plate movements, volcanic activity, and hydrothermal circulation. Hot springs brought dissolved minerals, including gold and silver, to the surface, precipitating them along fissures.

  
  

• Structural Control: Gold mineralization is strongly controlled by steep fault structures (like the Post-Genesis Fault) and favorable sedimentary beds.

  
  

• Alteration: Accompanying mineralization, there's often alteration of the host rocks, including decarbonatization (removal of calcite, creating a porous rock) and silicification.

• Mining Challenges: The fine-grained nature of the gold and its association with sulfides mean that sophisticated metallurgical processes like roasting or autoclave treatment are often required for extraction.