Indonesia sets its August reference prices, and a three dollar move lifts a coal royalty band

Indonesia prices its own mining output twice a month, and the exercise is more consequential than its routine appearance suggests. On 3 August 2026 the Directorate General of Minerals and Coal at the Ministry of Energy and Mineral Resources issued Ministerial Decision No. 312.K/MB.01/MEM.B/2026, fixing the metal mineral reference price and the coal reference price for the first period of August 2026. These are the numbers that convert physical tonnes into a value the state can tax, audit, and forecast against. This period they moved in two directions at once, and one of those moves crossed a threshold that carries a direct royalty consequence.

What the ministry published on 3 August

The coal reference price, known in Indonesia as Harga Batubara Acuan or HBA, is set for four calorific tiers. For the first period of August 2026, the headline grade of 6,322 kcal per kilogram GAR was fixed at US$124.44 a tonne, down from US$131.85 in the second period of July. The three lower tiers went the other way. HBA I, covering coal at 5,300 GAR, rose to US$93.27 a tonne from US$89.90. HBA II at 4,100 GAR rose to US$65.48 from US$63.25. HBA III at 3,400 GAR edged up to US$45.27 from US$45.08.

The same decision fixed the metal mineral reference price, or Harga Mineral Acuan, across the commodities Indonesia produces at scale. Nickel was set at US$15,691 per dry metric tonne. Cobalt was fixed at US$33,677 per dmt, copper at US$9,319.82, copper concentrate at US$4,872.12, aluminium at US$2,910.93, zinc at US$3,586.90, zinc concentrate at US$56.49, and lead at US$1,009.29.

Read as a market report, this is unremarkable. Read as a valuation instrument, it is the moment when a very large amount of Indonesian resource output receives its official price for the next two weeks.

A three dollar move that changes a royalty band

The reason the HBA I figure deserves attention is structural rather than dramatic. Under Government Regulation No. 19 of 2025, in force since 26 April 2025, coal royalty is no longer a single rate. It is banded, and the band is selected by the reference price itself. For open pit coal above 5,200 kcal per kilogram, the tariff is 9.5 percent when HBA sits below US$70, 11.5 percent when it sits between US$70 and US$90, and 13.5 percent once it reaches US$90 or above.

In the second period of July, HBA I stood at US$89.90. That is ten cents below the threshold. In the first period of August it stands at US$93.27.

A movement of US$3.37 in a published reference price has shifted a grade of Indonesian coal from the 11.5 percent royalty band into the 13.5 percent band. The tonnage did not change. The geology did not change. The valuation did.

This is what a progressive tariff is designed to do. When prices strengthen, the state captures a larger share without renegotiating a single contract, and when prices soften the burden eases automatically. The design spares both government and industry the friction of periodic bargaining. It also means that the accuracy and timeliness of the reference price now carry real fiscal weight, because the price is not merely descriptive. It is operative.

What the metal reference prices say

The nickel figure works the same way. Under the 2025 regulation, nickel ore carries a banded royalty running from 14 percent to 19 percent, selected by the metal reference price. The bands begin at 14 percent below US$18,000, move to 15 percent between US$18,000 and US$21,000, to 16 percent between US$21,000 and US$24,000, to 18 percent between US$24,000 and US$31,000, and reach 19 percent at US$31,000 and above.

At US$15,691, the August reference price sits inside the lowest band. Nickel ore is therefore priced for royalty at 14 percent this period. Processed products sit lower by design, which is the point of the downstreaming policy. At this reference level, nickel pig iron carries 5 percent, ferronickel 4 percent, nickel matte 3.5 percent, and mixed hydroxide precipitate a flat 2 percent. The gap between ore and processed product is the fiscal expression of Indonesia's preference for value added at home.

For operators, the practical reading is that the royalty base is transparent and forecastable. For provincial and district governments that depend on revenue sharing from mineral and coal royalties, the same transparency allows a more disciplined budget projection than a single flat rate ever permitted.

A second pricing system runs alongside it

Coal and metals are not the only resource output Indonesia prices officially. Two days before the ministry issued its August reference prices, the Ministry of Trade set the export benchmark price for mining products subject to export duty through Ministerial Decision No. 1669 of 2026. Gold was fixed at US$130,921.50 per kilogram for the period from 1 to 14 August 2026, down from US$131,839.51 for the second half of July, a decline of 0.7 percent. The underlying reference price fell to US$4,072.12 per troy ounce from US$4,100.67.

Tommy Andana, Director General of Foreign Trade at the Ministry of Trade, attributed the softening to stronger major currencies, rising international bond yields, and interest rates that continue to hold at levels which draw investors toward instruments with more predictable returns.

Two ministries, two instruments, two schedules, and a single underlying task: to attach a defensible number to material leaving the ground.

Why the base matters more than the rate

The fiscal stakes are visible in the sector's revenue trajectory. Non tax state revenue from minerals and coal reached Rp48.95 trillion between January and April 2026, growing 6.21 percent year on year, and had climbed to approximately Rp56 trillion by 15 May, according to Tri Winarno, Director General of Minerals and Coal. The full year target for 2026 is Rp133.93 trillion, an increase of 7.36 percent on the Rp124.75 trillion collected in 2025.

Against a target of that size, the quality of the valuation base matters at least as much as the level of the rate. A rate applied to an inaccurate base yields an inaccurate result, and no amount of tariff adjustment repairs it.

Indonesia has built a working system for pricing what a mine sells. The next frontier is pricing what a mine changes.

Sirkularium's view

The reference price system deserves recognition for what it does well. It is published on a fixed schedule, it is grounded in observable market data, it is legally binding, and since 2025 it is wired directly into a progressive tariff structure. Few resource economies have moved this far toward automatic, rules based revenue capture. Government stakeholders should read the August figures as evidence that the architecture is functioning as intended.

The opportunity ahead lies in extending the same discipline to the other half of the ledger. HBA and HMA price the saleable product. They do not price the condition of the land, the watershed, the soil, the forest cover, or the fisheries that a mining concession touches over its life. Indonesia already has a regulatory methodology for that side of the balance sheet in Permen LH No. 7 Tahun 2014, which sets out how ecological damage, environmental economic loss, and recovery cost are to be calculated. What is missing in most operations is not the method but the practice: a periodic, independently verified valuation built from remote sensing and geographic information system data cross checked against ground measurement, aligned with the operation's AMDAL commitments and its reclamation guarantee.

For mining operators, the case for adopting that practice is straightforward and increasingly commercial. An operator that can present the Ministry of Environment with a defensible, methodologically standard valuation of its environmental position, updated on a schedule rather than assembled under pressure, is in a materially stronger position than one that cannot. It shortens permitting conversations, supports reclamation planning, and turns environmental performance into a documented asset rather than a contingent liability.

For government and public institutions, the watch items for the rest of August are straightforward. Whether HBA I holds above the US$90 threshold in the second period will determine if the higher band persists. Whether the nickel reference price approaches US$18,000 will determine if the ore band moves off its floor. And whether the reclamation and ecosystem side of resource valuation receives the same institutional rigour now applied to the sales side will determine how complete Indonesia's picture of its own resource wealth eventually becomes.