Hardrock Gold Mining & Smelting Process 🏆

This video is a special collaboration with the crew over at @mineoperator and the one and only @Danhurd . I was invited down to California to explore a fascinating hard-rock gold mine that’s been back in operation for about seven years.

We go underground to pull a one-ton bulk sample from the "45 level," specifically targeting a high-grade section of the footwall vein. This area is known for its "sugar quartz" and deep purple oxidation—classic indicators of rich California gold.

The Mission: Bulk Sampling & Recovery Testing
The goal was simple: take a raw sample from the mine and see how our recovery on the table compares to their professional channel assays.

The Process:

Mucking & Hauling: We used a custom headframe and skip bucket system to haul the ore up a 55-degree incline and into the dump trailer.

The California Mill Run: We ran the first 1,700 lbs through the Mine Operator’s setup, including a jaw crusher, screen deck, and a Stutenroth mill.

The MBMM Shop Test: I brought 114 lbs of the high-grade back to my shop to run through our 6x10 jaw crusher, hammer mill, and 4x8 shaker table for a final precision cleanup.

The Chemistry & Smelt
To get the final numbers, we performed a bismuth fire assay on the concentrates.

Flux Recipe: 500g Soda Ash, 250g Anhydrous Borax, and 250g Silica Sand.

Collector Metal: 33g of Bismuth to "rain down" and catch the fine 200-mesh gold.

Final Result: After cupelling the button, we ended up with a beautiful precious metal bead.

The Final Math
Sample Weight: 114 lbs (0.057 tons)

Bead Weight: 0.257g

Calculated Grade: ~4.51 g/ton (raw)

Estimated Gold Grade: At 80% purity, that’s roughly 3.6 g/ton—confirming the mine's recent assays almost perfectly!

CHECK OUT THE TEAM:

Mine Operator: These guys are doing incredible work rebuilding this mine. Check out their channel here: @mineoperator

Dan Hurd: Watch Dan find his first-ever California gold in his companion video: @Danhurd

WANT THE GEAR?
If you're interested in the jaw crushers, hammer mills, or shaker tables used in this video, visit our website or send us an email!

#GoldMining #HardRockMining #CaliforniaGold #MineOperator #DanHerd #MBMMLLC #GoldAssay #Geology #MiningEquipment

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