• Profiting from Extremely Low‑Grade, Free‑Milling Gold Tailings
  • 1. The challenge of ultra‑low grades
  • 2. Plant configuration and throughput
  • 3. Gold recovered at 0.06 g/t
  • 4. Operating expense – almost zero
  • 5. Adding a fine‑grinding stage
  • 6. Why patience pays off
  • 7. Bottom line

Profiting from Extremely Low‑Grade, Free‑Milling Gold Tailings

This article shows how even ultra‑low‑grade, (0.06 g t⁻¹) can be turned into a by first using a simple, solar‑powered sluicing plant (4 × 2 t h⁻¹) that recovers about 10 g of gold per day, generating roughly US $30,000 per month with virtually no fuel cost; if the material is then milled to 70 µm (≈200 mesh) the recoverable grade doubles to 0.12 g t⁻¹, boosting revenue to around US $60,000 per month after modest milling expenses—demonstrating that careful sizing and a staged approach (, only when justified) avoids the 50 %+ losses typical of and turns a seemingly worthless resource into a high‑margin, low‑environmental‑impact cash flow.

An example of how 0.06 g/t gold can generate solid cash flow without leaching

1. The challenge of ultra‑low grades

A of 0.06 g t⁻¹ (6 g t⁻¹ × 10⁻³) is usually regarded as uneconomic for conventional processing. In many this grade is used to mislead investors or partners, because the actual metal content is so small that it appears negligible.

Nevertheless, when the gold is already **** () the material can be recovered directly by , bypassing the costly and environmentally demanding leach stages. The key is to design a simple, that while keeping operating costs to a minimum.

2. Plant configuration and throughput

• Sluice capacity: 2 t h⁻¹ per unit
• Number of sluices: 4 (operating in parallel)
• Total throughput: 2 t h⁻¹ × 4 = 8 t h⁻¹

3. Gold recovered at 0.06 g/t

Parameter	Value
Grade (free‑milling)	0.06 g t⁻¹
Throughput	8 t h⁻¹
Gold recovered per hour	0.06 g t⁻¹ × 8 t h⁻¹ = 0.48 g h⁻¹ (≈ 0.5 g h⁻¹)
Gold recovered per day (24 h)	0.5 g h⁻¹ × 24 h = 12 g (conservative estimate: 10 g)
Gold recovered per month (30 days)	10 g d⁻¹ × 30 d = 300 g
Current gold price	Sunday, January 11 2026, 00:24:10: US $143.97
Estimated gold purity	95%
Market value (US $ = US $ 60 g⁻¹)	300 g × US $100 g⁻¹ = US $41032.39

Even with a modest recovery efficiency (≈ 80 %), the plant can generate US $41032.39 per month from material that most operators would deem worthless.

4. Operating expense – almost zero

• Water supply: pumped from a nearby source; the pump can be driven by a (PV) array sized to the required flow.

• Power: Solar PV eliminates diesel or grid electricity costs; excess generation can be stored in batteries for night operation.

• Labor: One operator per shift to monitor sluice flow and perform routine cleaning.

• Consumables: Minimal

Result: Operating cost ≈ US $ 200 – US $ 2 000 month⁻¹, yielding a net profit margin well above 90 %.

5. Adding a fine‑grinding stage

If the are milled to a finer size (), the liberated gold surface area increases, effectively doubling the recoverable grade to 0.12 g t⁻¹.

Parameter	Value
New grade (after milling)	0.12 g t⁻¹
Gold recovered per hour	0.12 g t⁻¹ × 8 t h⁻¹ = 0.96 g h⁻¹
Gold recovered per day	0.96 g h⁻¹ × 24 h ≈ 23 g
Gold recovered per month	23 g d⁻¹ × 30 d ≈ 690 g
Revenue (US $ 60 g⁻¹)	690 g × US $143.97 g⁻¹ ≈ US $94374.50
Additional milling cost*	US $ 10 000 – US $ 15 000 month⁻¹
Net profit (approx.)	US $40,000 – 79374.49815 month⁻¹

includes electricity (solar‑powered or grid‑connected), wear parts, and labor. Even after accounting for this expense, the net profit roughly doubles compared with the straight‑sluice scenario.

6. Why patience pays off

• Avoid premature leaching: Initiating a on material that has not been sized correctly can waste > 50 % of the gold, turning a potentially profitable operation into a loss‑making one.

• Optimize before scaling: By first establishing the , operators capture the bulk of with negligible capital.

• Add milling only when justified: Once the baseline cash flow is proven, the decision to invest in a mill can be based on clear financial returns rather than speculation.

7. Bottom line

Even a 0.06 g t⁻¹ free‑milling resource—often dismissed as “too low grade”—can be turned into a high‑margin, low‑environmental‑impact business:

1. Sluice plant (4 × 2 t h⁻¹) → ~US $ 30 k month⁻¹ profit, virtually zero fuel cost.

2. Optional fine‑grinding → grade doubles, profit climbs to ~US $ 60 k month⁻¹ after milling expenses.

The example demonstrates that, with the right equipment and a disciplined process flow, become a cash‑generating asset rather than a waste stream. The key is to recover the liberated gold first, then consider milling or leaching only after the economic baseline is secured.