Fully hydraulic wireline exploration drilling rigs for gold prospecting rely on the core technology of efficient continuous core sampling. Core analysis and geological logging then pinpoint the location, grade, and size of the gold deposit. This technology is well-suited for gold exploration in hard rock, deep boreholes, and complex formations in Africa.
I. Core Principles (Advantages of Wireline Core Sampling)
Core Sampling Without Drilling: After the inner tube is filled with core material, a retrieval tool and wire rope are used to pull the inner tube out of the drill pipe for core sampling. The drill pipe remains inside the borehole, significantly reducing drilling time and increasing efficiency by 30%–50% compared to conventional drilling.
Fully Hydraulic Drive: Powerful, precise speed control, and easy operation, suitable for deep boreholes (500–2000m), hard rock (granite, metamorphic rock), and complex formations.
High Core Fidelity: Dual-tube/single-tube corers protect the core material, reducing breakage and contamination, which is beneficial for gold grade and mineralization analysis.
II. Gold Mine Exploration Process (Drilling Rig + Geology + Laboratory Testing Integration)
1. Preliminary Preparation (Target Finding + Hole Layout)
Geological Target Area Screening
Surface Prospecting Markers: Quartz veins (most common for gold), iron caps/limonite mineralization, pyrite/silicification/sericification alteration zones, tectonic fracture zones, old mine shafts/mining traces.
Geophysical and Geochemical Exploration First: Soil/rock geochemical exploration (trace gold anomalies), magnetic/electrical methods (identifying sulfide ore bodies and structures), remote sensing interpretation of structures and alteration zones.
Drill Hole Design
Hole Location: Holes are placed along the strike/dip of the vein, spaced 50–200m apart, controlling the ore body boundary and depth.
Hole Depth: Shallow holes verify surface mineralization (100–300m); deep holes trace deep blind ore (500–1500m).
Angle: Primarily vertical holes; when the ore body dips, use inclined holes (60°–85°) to penetrate the ore body.
Drilling Rig and Drilling Tool Configuration (Gold Mine Specific)
Drilling Rig: Fully hydraulic core drilling rig (e.g., YX-6, YX-8), suitable for deep holes, high torque, and high feed rate.
Drilling Tools: Wireline coring double-tube single/double-action core sampler (φ75/89/108mm), high-strength wireline coring drill rod, impregnated diamond drill bit (hard rock), retrieval tool, wireline winch.
Auxiliary Tools: High-pressure mud pump, mud purification system, bottom hole inclinometer, core box, sampling tools.
2. On-site Drilling Construction (Core Core Sampling)
1. Site and Hole Opening
Level the site, reinforce the foundation, level and stabilize the drilling rig to ensure hole position accuracy (error ≤ 0.5m). Hole Opening: Use a hole-opening drill bit + casing for wall protection to prevent hole collapse and ensure hole verticality.
2. Drilling + Wireline Coring Circulation
- Drilling Parameters (Reference for Hard Rock in Gold Mines):
- Drilling Pressure: 5–15kN (High for hard rock, low for soft rock)
- Rotation Speed: 300–800r/min (Medium-high speed for diamond drill bits)
- Pump Flow Rate: 80–150L/min, Flushing Fluid (Mud) Density 1.05–1.25g/cm³, Viscosity 18–22s, for carrying rock, wall protection, and cooling the drill bit.
- Coring Operation (Without Drilling):
1. Fill the inner tube with core material → Stop drilling and pump.
2. Lower the retrieval tool → retrieve the inner tube assembly → hoist to the surface using a winch.
3. Remove the core material, number it, pack it, and record the depth; reset the inner tube → continue drilling.
- Key Controls:
- Inclination measurement every 20m to ensure borehole inclination ≤1°/100m, avoiding deviation from the ore body.
- Core recovery rate ≥90% (≥95% for gold orebody sections) to ensure complete geological information.
3. Core Analysis and Gold Deposit Evaluation (Key to Prospecting)
Field Geological Logging: Describe lithology, mineralization (pyrite, chalcopyrite, etc.), alteration, structure, and gold occurrence state (granular gold, fractured gold, enclosed gold) segment by segment to delineate gold mineralization strata.
Sampling and Testing: Continuously groove samples are taken from gold mineralization sections (sample length 1–2m, sample weight ≥1kg) and sent to the laboratory for gold grade analysis (Au g/t).
- Analyze associated elements (Ag, Cu, Pb, Zn, As, Sb) to determine the deposit type and genesis.
Orebody Delineation:
- Delineate gold orebody according to industrial indicators (boundary grade ≥0.5g/t, minimum industrial grade ≥1g/t, minimum mineable thickness ≥0.5m) and calculate resource/reserve quantities.
- Combine borehole profiles and plan views to draw a ore body morphology diagram and determine the next exploration/drilling direction.
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