Eight rigorously controlled stages from raw doré intake to internationally certified 999.9 investment-grade bullion.
Uganda's gold arrives from artisanal and small-scale mines in many forms — alluvial dust, nuggets, and cast doré bars — at purities ranging from 40% to 90% gold content. The journey from raw material to a certified 999.9 investment-grade bar involves multiple scientifically-controlled stages, each one documented, verified, and designed to maximise both purity and recovery.
Our process combines two classical refining methods — Miller Chlorination (patented 1867, achieves 99.5% purity) and Wohlwill Electrolysis (patented 1874, achieves 99.99% purity) — with modern laboratory assaying, digital chain-of-custody documentation, and certified output marking. The result is gold that meets LBMA Good Delivery standards.
Every stage is conducted under CCTV, with dual-operator sign-off at critical control points. No gram of gold enters or leaves the process stream without a corresponding record. Your material is never mixed with another client's consignment.
All gold consignments are received at our secure intake counter by a licensed intake officer. Your material is photographed, weighed on certified scales (accurate to 0.01g), and assigned a unique Consignment Reference Number (CRN). A sealed sample is drawn immediately in the client's presence. You receive a Goods Received Note (GRN) with the gross weight and condition.
Client identity is verified against Uganda National ID, passport, or company documents as part of our KYC/AML compliance process. All consignment details are entered into our secure, timestamped digital registry.
Before the material enters the refining stream, it undergoes X-Ray Fluorescence (XRF) analysis — a non-destructive screening method that provides an elemental breakdown within 60 seconds. XRF identifies gold content and key impurities (silver, copper, zinc, iron, lead) at ±0.1–0.5% accuracy.
XRF results are used to select the correct refining pathway (Miller or Wohlwill), estimate reagent quantities, and provide the client with an immediate indicative purity reading. XRF does not replace fire assay — it informs the process and serves as an early dispute-prevention tool.
Raw material — often a mix of alluvial dust, nuggets, and fragments at varying purities — is combined with flux agents (borax, soda ash, and silica) in a graphite crucible and smelted in our induction furnace at 1,064°C (gold's melting point). The flux chemically binds impurities into a slag layer that floats to the surface and is skimmed off.
The result is a homogeneous, cast doré bar — a semi-refined alloy of gold and silver with trace base metals removed. This bar is the starting point for both assay sampling and the subsequent refining stages. The process is conducted under an exhaust ventilation system to safely manage chloride and sulphide fumes.
This is the definitive purity test. A representative sample (typically 250mg) is drawn from the smelted doré bar. The fire assay proceeds in six stages: (1) Sample prep — the sample is weighed and combined with lead oxide flux and silver collector; (2) Fusion — fired in a muffle furnace at 900–1,000°C for 45 minutes; (3) Cupellation — the molten lead absorbs base metals, leaving a gold-silver alloy bead (the "prill"); (4) Parting — the prill is dissolved in hot nitric acid to remove silver; (5) Final weighing — the pure gold residue is weighed to ±0.01% accuracy; (6) Certification — an Assay Certificate is issued with purity, weight, and assayer signature.
A referee sample from the same lot is retained in sealed storage for 90 days — available for independent re-test in the event of any dispute.
For material below 99.5% purity, the cast doré bar undergoes the Miller Chlorination Process (patented by Francis Bowyer Miller, 1867). Chlorine gas is bubbled through the molten gold alloy at approximately 1,100°C. Chlorine preferentially reacts with silver and base metal impurities to form volatile chloride compounds, which rise to the surface as a crust and are removed.
The process is run until chlorine gas begins to emerge unreacted — confirming that all silver and base metals have been converted and removed. The result is gold at 99.5% (995 fineness). For clients requiring this standard (e.g., for jewellery manufacture or industrial use), the process ends here with casting and certification. For LBMA Good Delivery bars (999.9), the material proceeds to Wohlwill electrolysis.
To achieve 999.9 fineness (four nines), the 99.5% Miller-refined gold undergoes Wohlwill electrolytic refining (patented by Emil Wohlwill, 1874). The gold is cast as an anode and immersed in a heated gold chloride (HAuCl₄) electrolyte solution. A low direct current is applied.
Gold dissolves from the anode and deposits as pure 999.9 gold crystals on a stainless steel cathode sheet. All remaining silver and base metal impurities remain in solution or fall as anode slime — which is separately processed for silver and platinum group metal recovery. Cathode sheets are harvested after 24–48 hours, washed, and weighed.
The Wohlwill process produces the highest achievable purity by any commercial refining method. The output meets LBMA Good Delivery Rule requirements for internationally tradeable bullion.
The refined gold crystals from the electrolysis cathodes are melted in a clean graphite crucible and cast into the client's chosen form — standard minted bars (1g to 400oz), granules for jewellery manufacture, or powder for industrial applications. Each bar is cast under an inert gas blanket to prevent oxidation.
Every bar is individually weighed on calibrated precision scales and stamped (hallmarked) with:
A signed Assay Certificate of Analysis is issued to the client, showing input weight, sample purity, output weight, gross metal accounting, and a traceability chain from intake CRN to final bar serial number. For export consignments, the certificate is countersigned and forms part of the DGSM export permit application package.
Settlement — whether we are buying the gold from the client or returning refined bars to them — is processed same day based on the fire assay result and the prevailing LBMA PM Gold Fix. Payment is made by bank transfer, mobile money (MTN/Airtel Uganda), or cash for amounts within legal limits.
Gold returned to clients is delivered in sealed, tamper-evident bags or boxes with bar serial numbers visible. Insured armed transport to the client's location in Kampala can be arranged on request.
The Miller Process exploits the thermodynamic preference of chlorine to react with silver and base metals before attacking gold. When Cl₂ is bubbled through molten gold alloy, AgCl (silver chloride), CuCl, and other chloride compounds form and migrate to the melt surface as a slag. The process endpoint is detected when unreacted chlorine gas begins to break through — indicating all reactive impurities have been converted. The gold retained in the crucible typically assays at 99.5%.
Key advantage: Rapid (4–6 hours), cost-effective, handles large volumes. Suitable as a primary refining stage before electrolytic upgrading.
Wohlwill electrolysis is the most precise gold refining method known. The chemistry is elegant: in a hot gold chloride solution, only gold (Au³⁺) has the right electrochemical potential to plate cleanly on the cathode. Silver precipitates as AgCl and sinks as anode slime; platinum group metals (if present) remain in solution. The cathode-deposited gold is mechanically pure to 999.9 — verified by post-process assay.
Key advantage: Highest purity achievable (999.9). Platinum group metal recovery from anode slime adds value for complex doré feedstocks. Essential for LBMA Good Delivery compliance.
All material is weighed three times independently on two calibrated scales. Discrepancies greater than 0.05g trigger a hold and supervisor review before processing continues.
Every fire assay is run in duplicate. Both samples must agree within ±0.03%. If they diverge beyond tolerance, a third assay is run and the median result is used. Clients may request an independent re-assay of the retained referee sample at any time within 90 days.
No consignment moves from one stage to the next without two authorised staff members independently signing the stage completion log. This prevents errors and creates an unbroken accountability chain.
100% of the refining floor, assay lab, vault, and intake counter are under continuous CCTV recording. Footage is retained for 180 days. Clients with concerns may request review of footage relating to their consignment.
At the end of each shift, a mass balance is calculated: total gold input must equal total gold output plus process losses (within published tolerance limits). Unexplained variances trigger an immediate internal audit.
Finished bars are re-weighed, visually inspected for surface quality, and the serial number is confirmed against the consignment record before sealing. A final spot-check XRF is run on 10% of finished bars to confirm output purity.
Contact our team to discuss your consignment, get a preliminary estimate, or book a facility visit. We're available Monday to Friday 8:00–18:00 and Saturday 9:00–14:00.