My guess at this point that this is a epithermal gold deposit. Epithermal means that this is a hot system that was originally deposited at shallow to surface depths. Many deposits that have similar brecciaition and gold values associated with the silica stockwork veins have been classified as "Hot Springs" deposits. As a magma body rises in the crust (along some zone of weakness) ground water (meteoric water) is heated up and dissolves metal from the rocks they circulate through. As the superheated water comes close to the surface, it boils and metals are deposited in fractures. These fractures also seal up with deposited silica (quartz). When this happens the water is still being super-heated and it builds up tremendous pressure, the fractures have sealed up and the water has no place to go. Now this is where the brecciation comes in... once the built up pressure exceeds the strength and pressure from the confining rocks, a huge mega-ton explosion occurs, fracturing (brecciating) the confining rocks, blasting the new formed fractures with boilng mineralized water and deposition occurs. Over and over again the cycle repeats itself and you have an epithermal gold deposit forming over time. Usually to get economic amounts of gold deposited, these features can persisit for 100,000 years or so. If the rising magma is "wet" and most silicic magmas are, then highly minerlized water can enter this hydrothermal system and create polymetallic deposits like Camino Rojo.

I don't know if Camino Rojo is a "Hot Springs" deposit, but it has the hydrothermal breccias that are associated with epithermal deposits and a higher grade core (CR-6) that indicates more than one event of brecciation. This is a simplified explanation and hope it helps you visualize this type of deposit.