Hydrometallurgy, Gold ADR / Copper SX-EW & Heap Leach Operations
Heap Leach Irrigation Flux, PLS Flow & Metal Recovery Formula
Calculate Pregnant Leach Solution (PLS) Volumetric Flow (m³/hr), ADR/SX Stripping Efficiency (%), Daily Net Recovered Metal Mass (kg/d), and Daily Gold Equivalent (troy oz/d).
Subtract recycled Barren Leach Solution (BLS) grade—only NET delta (PLS - BLS) is captured in ADR carbon or SX-EW!
Oxide gold mines (cyanide drip irrigation -> Activated Carbon ADR / Merrill-Crowe) and oxide copper mines (dilute sulfuric acid irrigation -> Solvent Extraction Electrowinning SX-EW) percolate lixiviant across geomembrane-lined Heap Leach Pads at specific Hydraulic Application Flux J (typically 8–12 L/(hr·m²)): Total Pregnant Leach Solution flow is Q_PLS = (Pad_Area_m2 * Flux_L_hr_m2) / 1,000 m³/hr! Because Barren Leach Solution (BLS) exiting the carbon columns or raffinate pond is pumped straight back onto the heap carrying residual dissolved metal C_BLS (mg/L = g/m³), Net Daily Metal Plated/Eluted at plant availability A_avail is M_kg_d = (Q_PLS * (C_PLS - C_BLS) * 24 * A_avail) / 1,000 (and dividing grams by 31.1035 g/troy oz converts gold directly into payable troy ounces)!
Verify on an 80,000 m² Oxide Gold Leach Cell—Active_Pad_Area = 80,000 m² (8.0 ha, B2), Drip_Irrigation_Flux = 10.0 L/(hr·m²) (B3 -> PLS Flow = 800.00 m³/hr in E2), Pregnant_PLS_Grade = 2.50 mg/L Au (g/m³, B4), Barren_BLS_Return_Grade = 0.15 mg/L Au (B5 -> Carbon Column Adsorption Efficiency = 94.00% in E3), and ADR_Plant_Availability = 0.95 (95.0%, B6): Net Gold Captured hits (800 * 2.35 * 24 * 0.95) / 1,000 = 42.86 kg/d (E4), or 1,378.11 troy oz/d (E5)!
| Heap Leach ADR KPI (80,000 m², 10 L/hr·m², PLS=2.50, BLS=0.15 mg/L, 95% Avail) | Formula | Verified Output |
|---|---|---|
| Pregnant Solution Flow (m³/hr) | (Pad_Area_m2 * Flux_L_hr_m2) / 1000 | 800.00 m³/hr |
| Column Stripping Efficiency (%) | ((PLS_mg_L - BLS_mg_L) / PLS_mg_L) * 100 | 94.00% (87.50% @ PLS = 1.20) |
| Net Metal Recovered (kg/d) | (Q_m3_hr * (PLS - BLS) * 24 * Avail)/1000 | 42.86 kg/d (19.15 @ PLS = 1.20) |
| Payable Dore Equivalent (oz/d) | (Net_Metal_kg_d * 1000) / 31.1035 | 1,378.11 oz/d (615.75 @ PLS = 1.20) |
Closed-Loop Heap Leach PLS-BLS Net Metal Production Formula
Validate Pad_Area > 0, Irrigation_Flux in (1, 50] L/(hr·m²), 0 <= BLS_Grade < PLS_Grade, and Availability in (0, 1.0]!
=LET(ar_m, B2, fx_l, B3, pl_s, B4, bl_s, B5, av_f, B6, IF(OR(ar_m <= 0, fx_l <= 1, fx_l > 50, bl_s < 0, pl_s <= bl_s, av_f <= 0, av_f > 1), "Invalid Heap Leach Input", LET(q_pl, (ar_m * fx_l) / 1000, ROUND((q_pl * (pl_s - bl_s) * 24 * av_f) / 1000, 2))))Late-Cycle Mature Lift Leach-Curve Grade Decay Check (Set PLS Grade = 1.20 mg/L)
Simulate a mature leach lift after 60 days of percolation where Pregnant_PLS_Grade B4 declines from 2.50 to 1.20 mg/L while Barren Tail B5 stays at 0.15 mg/L: Column Efficiency E3 dips to 87.50% and Daily Gold Output drops to 19.15 kg/d (E4) = 615.75 troy oz/d (E5)!
=IF(ISTEXT(E4), E4, LET(kg_d, (((B2 * B3) / 1000) * (B4 - B5) * 24 * B6) / 1000, ROUND((kg_d * 1000) / 31.1035, 2)))Try the example
Use the original values or change them to test your understanding.