# Insertion rates

> ~20% total, 4–6%/type; compute the achieved rate

Source: https://geodb.io/guide/topic/qaqc_insertion_rates/ · Category: QAQC
"5%" and "20%" are **both** correct — 5% is per control type, 20% is the
total. Simón's survey of seven QA/QC consultants all lands near 20%
(range 15–25%), and *"a 20% control-sample insertion rate has practically
become an industry standard."*

His recommended breakdown for core drilling:

| Type | Rate |
|---|---|
| Duplicates (twin 2% + coarse 2% + pulp 2%) | 6% |
| Standards (CRMs) | 6% |
| Blanks (coarse 2% + pulp 2%) | 4% |
| Check samples (umpire lab) | 4% |

The 1999 TSE-OSC regulatory floor: 1 duplicate + 1 blank + 1 standard per
20 samples = 15%. Practical refinement (Bloom): match blank spacing to the
lab's rack size — one per 25–40 samples tracks a fire-assay rack.

## The finding that actually bites

**Achieved ≠ planned, routinely.** Rainy River planned 3.3–5% CRMs and
achieved **2.2% on average**; blanks landed at 0.7–1.4%; prior operators
submitted none at all. The rate that matters is the one **computed from
the data** — per period, per hole — never the one in the protocol
document. And rigid rates aren't sacred: tailor proportions to the
problems your program actually has.

## In geoDB

Your planned rates live in the project's **QC insertion protocols**;
geoDB computes actual QC presence per certificate and reports low
insertion in its batch QC summary (flagging under ~3–5%). The approval
page states the achieved rate and any missing QC type right above the
approval decision, and stores what it said with the approval — but it is
**guidance, not a block**: you may approve any certificate you want to,
including one with no QC on it at all. Keep the achieved-vs-planned
comparison in your own review habit.