Sample evidence guide
Build a Chain of Custody That Survives Every Handoff.
A reliable custody trail connects the physical sample to every identifier, container, custodian, shipment, laboratory receipt and review decision. Design each handoff as a recorded event with a clear exception path.
Separate identity, custody and analytical quality
These controls support one another but answer different questions. Identity asks whether the label, database record and physical container refer to the same material. Custody asks who controlled it, where, when, in what condition and under which transfer. QA/QC asks whether sampling and analysis produced suitable data. Keep the records connected without treating one as proof of the others.
The official JORC Code 2012 Edition includes Table 1 criteria covering sampling techniques and data, including sample security and quality-control matters. JORC is a public-reporting code for its applicable context—not a universal operating procedure. Check the current publisher library, listing rules and the reporting regime that actually applies to the project.
Define the minimum custody event
Every transfer should create a durable event rather than overwrite the current holder. At minimum record:
- the stable sample, container, batch and shipment identifiers;
- event type, local time, time zone and system receipt time;
- relinquishing and receiving parties, roles and acknowledgements;
- location or controlled location reference appropriate to the sensitivity of the project;
- seal identifiers and observed condition before and after transfer;
- quantity, container count and any mismatch, damage, contamination concern or missing item;
- supporting document or photograph reference, device/source and reason for later correction.
The US Environmental Protection Agency's Contract Laboratory Program field sampler guide is not a mining standard, but it provides a useful custody pattern: unique sample numbers, chain-of-custody records, custody seals and signed relinquishment/acceptance at each transfer. Adapt principles only after the project sampling plan and qualified reviewers determine what is appropriate.
Map the chain before choosing software
- Plan: approve the sampling plan, identifier rules, container and label rules, QA/QC insertions, required roles and laboratory instructions.
- Collect: create the sample record at the point of work and bind it to the physical identifier without re-keying where practical.
- Secure: record packaging, grouping, seals, storage and the person responsible before dispatch.
- Transfer: require both sides of each handoff and retain refused, incomplete or disputed transfers as exceptions.
- Receive: reconcile expected and received items, seal condition and laboratory identifiers before analysis proceeds.
- Import: validate file provenance, schema, units, methods and sample identifiers; quarantine unmatched or duplicate results.
- Review: keep analytical QA/QC decisions, re-assay instructions, exclusions and approval separate from raw results.
Decision checklist
- Can the team reconstruct every sample's route without relying on one person's memory?
- Can a transfer remain pending until both parties agree, with escalation for overdue acceptance?
- Does correction preserve the original event, actor, reason and authorisation?
- Can duplicate labels, broken seals, missing containers and unexpected laboratory identifiers be quarantined?
- Can exports retain events, attachments, code lists, units and relationships in usable formats?
Test the exception path
A “happy path” demonstration proves little. Use fictional samples to test duplicate identifiers, an unreadable label, a broken seal, fewer containers received than dispatched, an unrecognised laboratory batch, a revised certificate and a result for an unexpected sample. Confirm that the system blocks inappropriate release, preserves source files and routes each decision to the correct qualified reviewer.
Limitations
This guide does not define a sampling programme, analytical method, QA/QC regime, resource-reporting conclusion or legally sufficient chain of custody. Requirements depend on commodity, deposit, method, laboratory, contract, jurisdiction and reporting purpose. Software can organise evidence; it cannot determine geological reliability or replace accountable professional judgement.
Continue the sample review
Review the OreLynx exploration and sample workflow, test vendor claims with the software evaluation guide, and include integration and portability questions in the laboratory handoff.