39. Drug Quantity Aggregation — The Formula (Vic & Cth)¶
Scope and currency
Cheat sheet · Drugs, Poisons and Controlled Substances Act 1981 (Vic) ss 70(1), 71, 71AA, 73(2) + Criminal Code Act 1995 (Cth) Part 9.1, Divisions 311–312
One formula, two regimes. Both jurisdictions aggregate different drugs the same way — convert each drug to a fraction of its own threshold and add the fractions; if the sum reaches 1, the threshold is met. What differs is what goes on top of the fraction: Victoria may use the whole dilute mixture weight (in defined circumstances) and recognises course-of-conduct trafficking; the Commonwealth works on pure weight only (s 312.1) but gives explicit statutory pathways for combining parcels and occasions. Step one is always: which jurisdiction?
THE FORMULA¶
The core equation (both regimes): Σ ( quantity of each drug ÷ that drug's own threshold ) ≥ 1 → the aggregated threshold is met. Victoria calls the result an "aggregated commercial" or "aggregated large commercial quantity" (s 70(1) DPCSA); the Commonwealth calls each fraction the "requisite fraction" (s 312.2).
Working it — five steps¶
| Step | What to do |
|---|---|
| 1 · Pick the tier | Decide which threshold you are testing — commercial or large commercial (Vic); trafficable, marketable or commercial (Cth). Use the same tier for every drug in the calculation. |
| 2 · Fix the numerator | Vic: apply the divisor rules below — the numerator is either the whole mixture weight or the pure weight. Cth: always the pure weight of the substance within the mixture (s 312.1). |
| 3 · Fix the denominator | That drug's own statutory threshold for the tier chosen — Vic: Schedule Eleven column; Cth: Schedule 2. |
| 4 · Divide, then add | Compute each fraction as a decimal and sum them. |
| 5 · Test against 1 | Sum ≥ 1 → aggregated threshold met. Sum < 1 → not met; fall back to the individual counts. |
Part 1 — Victoria (DPCSA)¶
VIC · s 70(1) Choosing the divisor — the three rules
Which Schedule Eleven column is the denominator, and what goes on top? Aggregation under s 70(1) lets the prosecution add together different drugs of dependence to reach a commercial or large commercial threshold where no single drug would suffice. The divisor depends on the drug's form. → Rule 1 — Narcotic plants (Part 2, Sch Eleven): divisor is the quantity in Column 2 (commercial) or Column 1A (large commercial). → Rule 2 — Drug in a MIXTURE (Part 3, Sch Eleven): if the drug is mixed with another substance and the total mixture weight is NOT LESS THAN the threshold in Column 2A (commercial) or Column 1B (large commercial), then use the actual mixture weight as the numerator, divided by that Column 2A / 1B threshold. → Rule 3 — PURE form (or mixture below Column 2A/1B): if the mixture's total weight is less than the Column 2A / 1B threshold, or the drug is unmixed, the divisor is the pure weight threshold in Column 2 (commercial) or Column 1A (large commercial). Cutting agents and other substances are strictly EXCLUDED from the numerator.
Worked example — the statutory example in s 70(1): Jack has 40 g pure heroin (commercial threshold 50 g), 80 g pure amphetamine (threshold 100 g) and 800 g pure THC (threshold 1 kg). No single drug meets its own threshold. Aggregate: 40/50 + 80/100 + 800/1000 = ⅘ + ⅘ + ⅘ = 12/5 = 2.4. Since 2.4 ≥ 1, an aggregated commercial quantity is established.
Ahmed — the three charging options for a single mixture¶
| Option | How it is charged | Basis |
|---|---|---|
| A · Individual pure counts | Ascertain the precise pure quantity of each drug in the mixture and present individual counts of trafficking on those pure weights. | Pure weight per drug |
| B · Single mixture count | Select only one of the drugs in the mixture and present a single count, relying on the entire weight of the mixture. | Column 2A / 1B |
| C · Statutory aggregation | Aggregate the drugs using the s 70(1) fractional formula and present a single count of trafficking in an aggregated quantity. | s 70(1) |
What the Crown CANNOT do (Ahmed; Pearce)
the Crown cannot prefer separate, parallel counts of commercial trafficking for multiple drugs in a single mixture by repeatedly using the total mixture weight for each count. That duplicates the offending and punishes the accused multiple times for a single physical act, breaching the rule against double punishment (R v Ahmed VSCA 270, Nettle JA; Pearce v R (1998) 194 CLR 610). Also: different drugs cannot be aggregated to make a basic traffickable quantity under s 73(2) — aggregation is confined to commercial and large commercial counts.
VIC · Giretti Course-of-conduct aggregation (the rolled-up count)
Can multiple transactions over time be rolled into one commercial count? Distinct from mixture aggregation. Under Giretti v R (1986) 24 A Crim R 112, trafficking may be established by showing the accused was "carrying on a business" of dealing in drugs, allowing multiple transactions across the indictment period to be charged as a single rolled-up count. → Evidentiary cumulation: the jury may look at the continuous nature, regularity, systematic structure and financial proceeds of the business as a whole to infer the total quantity trafficked over the period met the commercial or large commercial threshold — even if individual transactions were small or cannot be precisely dated. → Contemporaneous mens rea: the Crown must prove the accused intended to traffick in at least the commercial quantity contemporaneously with engaging in the business. That intention may be inferred if the accused actually knew, or was reckless — aware of a "significant or real chance" that their ongoing activities would cumulatively exceed the threshold (Mustica v The Queen VSCA 79).
Part 2 — Commonwealth (Criminal Code, Part 9.1)¶
Pure weight only
the Code rejects state-style dilute weight calculation. Thresholds for border controlled drugs and precursors apply exclusively to the pure weight of the substance found within a mixture (s 312.1). There is no Commonwealth equivalent of the Victorian Column 2A / 1B mixture rule.
The Commonwealth combining pathways¶
| Pathway | Provision | Rule |
|---|---|---|
| Different parcels, same occasion | s 311.1(1) | Trafficking, manufacturing, importing, exporting or possessing different parcels on a single occasion may be charged as one offence; the quantity is the sum across all parcels. The prosecution must set out the particulars of each parcel in the charge. |
| Trafficking controlled drugs | s 311.8 | Aggregate across different occasions if each offence was committed within 7 days of another. |
| Manufacturing controlled drugs | s 311.11 | Combine if each offence occurred within 7 days of another. |
| Importing / exporting border controlled drugs | s 311.13 | Aggregate across multiple importations/exportations if each offence was within 30 days of another. |
| Possession of unlawfully imported substances | ss 311.14, 311.15 | Combine if each offence occurred within 7 days of another. |
| Importing / exporting precursors | s 311.16 | Combine if each offence occurred within 30 days of another. |
| Anti-double-counting | s 311.22 | The same parcel cannot be counted more than once — e.g. counting it when possessed for sale and again when actually sold. |
Why the time windows exist: Subdivision C targets offenders who deliberately split shipments or transactions to stay under threshold penalties — so the 7-day (trafficking, manufacture, possession) and 30-day (import/export, precursors) windows are the outer limits of aggregation across occasions.
CTH · Subdiv B Organised commercial activity (the federal 'business' count)
Proving quantity through repeated offending rather than individual transactions? For serious commercial charges (e.g. trafficking under s 311.2, importing/exporting under s 311.4), the prosecution may prove the quantity element by showing the accused engaged in an "organised commercial activity" involving repeated offences. Procedural relaxation: the prosecution is relieved of specifying or proving the exact dates or exact quantities of each individual transaction in the course of that activity. → ⚠ The trade-off — loss of presumptions: if the Crown relies on the organised-commercial-activity provisions, the standard rebuttable presumption of "intent to sell" triggered by possessing a trafficable quantity under s 302.5 does NOT apply. The prosecution must affirmatively prove actual commercial intent and involvement in the business. → Relationship to Giretti: this is the federal alternative to a State Giretti count — but Giretti reasoning cannot be used directly to establish a Division 302 offence.
The requisite fraction (s 312.2) — combining different kinds of drugs: where a single offence involves more than one class or kind of serious drug, plant or precursor, aggregate using the requisite fraction method. Under s 312.2(3) each fraction = actual pure weight ÷ that substance's own statutory threshold (trafficable, marketable or commercial). The threshold is satisfied if the sum of the requisite fractions is ≥ 1.0.
Worked example — s 312.2 (single importation)¶
| Substance | Pure weight | Commercial threshold (Sch 2) | Requisite fraction |
|---|---|---|---|
| Opium | 9.5 kg | 20 kg | 9.5 ÷ 20 = 0.475 |
| Oxycodone | 3 kg | 5 kg | 3 ÷ 5 = 0.600 |
| SUM | — | — | 1.075 ≥ 1.0 → threshold MET |
Result: because the combined requisite fractions total 1.075, the accused may lawfully be charged with importing a commercial quantity of a combination of border controlled drugs — even though neither substance alone reaches its own commercial threshold.
Victoria vs Commonwealth — the key differences¶
| Victoria (DPCSA) | Commonwealth (Code Pt 9.1) | |
|---|---|---|
| Weight basis | Dilute mixture allowed — whole mixture weight where it meets Column 2A / 1B; otherwise pure. | Pure weight only (s 312.1) — no dilute calculation. |
| Combining drugs | s 70(1) fractional formula; sum ≥ 1. | s 312.2 requisite fraction; sum ≥ 1.0. |
| Tiers it applies to | Commercial and large commercial only — not traffickable (s 73(2)). | Trafficable, marketable and commercial. |
| Combining across occasions | Common-law Giretti rolled-up count (business). | Statutory — Subdiv C, with 7-day / 30-day windows. |
| Business-style proof | Giretti + contemporaneous mens rea (Mustica). | Organised commercial activity (Subdiv B) — but loses the s 302.5 presumption. |
| Anti-duplication | Ahmed / Pearce — no parallel counts on the same mixture weight. | s 311.22 — no parcel counted twice. |
The five traps¶
• Mixing tiers: never combine a commercial fraction with a large commercial fraction — run the calculation separately for each tier.
• Wrong numerator: in Victoria, using the mixture weight when the mixture falls below Column 2A / 1B is an error — you must revert to pure weight and exclude cutting agents.
• Traffickable aggregation: different drugs cannot be aggregated to reach a traffickable quantity in Victoria (s 73(2)).
• Parallel mixture counts: charging each drug in one mixture at the full mixture weight is double punishment (Ahmed; Pearce).
• Federal presumption: running an organised commercial activity case forfeits the s 302.5 intent-to-sell presumption — you must prove commercial intent affirmatively.