Heap Leach ADR & Carbon Plant: Reagent-Handling Equipment
Cyanide makeup, lime/caustic pH control, loaded-carbon acid wash and antiscalant dosing — the equipment behind each reagent step in a heap-leach carbon-adsorption / ADR circuit, with real figures from a public 2025 heap-leach gold-silver project as a worked example.
Free: ADR & Carbon Plant Reagent-Handling Checklist. Cyanide, caustic, acid wash and antiscalant — the equipment checklist for each step.
Get the Checklist →A Nevada Heap-Leach Gold-Silver Project, by the Numbers
The figures below come from one public record: a 2025 NI 43-101 preliminary economic assessment (PEA) filed for a Nevada open-pit heap-leach gold-silver project. LibertyCES prepared this page independently from that public filing and is not affiliated with the project, its engineers or its ownership; the project is used here only as a real-world example, not named. Figures are preliminary economic-assessment estimates and may change with further study.
Stationary jaw-and-cone crushing capacity, 80% passing 3/4"
Reported sodium cyanide consumption in metallurgical testwork
Reported lime consumption in metallurgical testwork
Valley-fill heap leach pad capacity, synthetic + amended-clay liner
The Circuit, Step by Step
Simplified from the PEA's process description. In this project's confirmed scope, gold and silver stop at loaded carbon, which ships off-site — the "beyond the PEA" section below covers what a full on-site ADR circuit adds when a project runs one instead.
- 1
Crushing
A 350 TPH stationary jaw-and-cone circuit reduces ore to 80% passing 3/4", running about 4.5 days a week on double 12-hour shifts. Oversize from a 3/4" screen recycles back to the cone crusher.
Equipment: Jaw crusher, cone crusher, screening deck, conveying and feed equipment
- 2
Heap leach pad
A valley-fill facility with a synthetic liner over an amended-clay underliner. Crushed ore is stacked in 10–20 ft lifts by end-dump trucks, with cyanide solution applied and collected through a perforated pipe system and solution manifold.
Equipment: Solution distribution manifold, collection piping, irrigation/application equipment
- 3
Pregnant solution storage
Pregnant leach solution (PLS) draining from the heap collects in a Pregnant Solution Storage Tank (PSST) ahead of the carbon circuit.
Equipment: PLS storage tank, transfer pumps
- 4
Carbon adsorption (ACA/CIC)
PLS is pumped through a series of activated-carbon adsorption / carbon-in-column (ACA/CIC) tanks, where gold and silver adsorb onto activated carbon as solution passes through.
Equipment: Carbon columns, inter-stage transfer pumps, carbon-retention screens
- 5
Barren solution return
Solution leaving the carbon circuit collects in a Barren Solution Storage Tank (BSST), where fresh sodium cyanide is dosed to hold working strength before the solution recycles back to the heap.
Equipment: Barren storage tank, cyanide makeup/dosing system, recycle pumps
- 6
Loaded carbon handling
In this project's confirmed scope, loaded carbon is shipped off-site to a toll refiner for metal recovery — there is no on-site elution, acid wash or electrowinning in the PEA as filed.
Equipment: Carbon handling/loadout equipment; see the labeled section below for what a full on-site ADR circuit adds
What a Full On-Site ADR Circuit Adds
Where a project runs on-site desorption instead of toll refining, three more reagent-handling steps come into scope, as general industry practice — not confirmed detail from this specific project's PEA, which ships loaded carbon off-site: elution (a hot caustic-cyanide eluant strips gold and silver back off the loaded carbon), acid wash (a dilute mineral acid, commonly hydrochloric, removes calcium-carbonate scale from the carbon before elution — skipping this is a common cause of poor elution efficiency), and electrowinning (recovers metal from the eluate onto steel wool or mesh cathodes). The free checklist below walks through the reagent-handling equipment for these steps.
Reagent-Handling Equipment, by Stream
| Reagent stream | What it needs |
|---|---|
| Cyanide (NaCN) makeup | Sized to hold a constant working strength in the barren solution — the reported testwork figure (< 0.14 lb NaCN/ton ore) is low for the industry; confirm your own project's figure from testwork, not this one, before sizing a dosing system. |
| Lime / caustic dosing | Cyanide leaching runs in an alkaline solution (roughly pH 10.5–11). Lime is the typical bulk pH reagent on the ore/heap side; caustic soda (NaOH) is a common alternative where faster dissolution or lower scaling is wanted. Low-pH interlocks on cyanide dosing are standard practice — cyanide releases as HCN gas if solution pH drops. |
| Carbon transfer | Abrasive, wet-carbon service between adsorption stages needs transfer equipment rated for that duty, not general-service slurry equipment. |
| Process water supply | The example project holds a water right for 361.966 acre-feet a year at up to 224 gpm; a pumping test on its existing well returned 210–220 gpm, with rehabilitation or replacement flagged as a real project need. |
ADR & Carbon Plant Reagent-Handling Checklist
Cyanide makeup and dosing, caustic/lime pH control, loaded-carbon acid wash, and antiscalant dosing — a working checklist for each reagent step, built to hand to a supplier alongside a spec.
Get the Checklist →More on Leach-Circuit and Cyanide Equipment
Hydrometallurgical Equipment Selection Guide →
Heap leach irrigation through SX-EW and dewatering — equipment at every leach-circuit stage.
Leach Circuit Bid Package Checklist →
What an EPC or mine owner sends a supplier to get a real quote, not a catalog guess.
Chrome Reduction & Cyanide Destruction pH/ORP Control →
Downstream of the ADR/carbon plant: destroying residual cyanide before discharge, not recovering metal.
Heap Leach Irrigation Equipment Selection →
Driplines, sprinklers and mining-configuration valves for the application side of the heap.
Certified, and One Supplier for the Reagent-Handling Package
CPUC Supplier Clearinghouse Certified MBE
Minority Business Enterprise under CPUC General Order 156 · VON 26001569
California Certified Small Business (Micro)
CA Department of General Services · Cert. ID 2028632
Submittal-ready cut sheets for any line above, basis-of-design and "or equal" comparisons, and no charge to review a spec before it's issued. See certifications or send a project to the Bid Desk.
ADR & Carbon Plant Reagent Handling: Common Questions
What is an ADR plant in gold and silver mining?
ADR stands for adsorption–desorption–recovery. It is the part of a heap-leach or CIL/CIP circuit where gold and silver dissolved in cyanide solution are adsorbed onto activated carbon (the adsorption stage), then stripped back off the carbon in a hot caustic-cyanide elution circuit (desorption), and recovered as metal, usually by electrowinning. Some projects run the full ADR sequence on site; others adsorb gold onto carbon on site and ship the loaded carbon to a toll refiner for the desorption and recovery steps instead.
What equipment does a heap-leach carbon adsorption (ACA/CIC) plant need?
At minimum: a pregnant-solution storage tank ahead of the carbon columns, a series of carbon-in-column (CIC) or activated-carbon adsorption (ACA) tanks with inter-stage transfer pumps and carbon-retention screens, a barren-solution storage tank, and a cyanide makeup/dosing system to bring barren solution back to working strength before it recycles to the heap.
Does every heap-leach project run its own on-site elution and electrowinning?
No. Some projects adsorb gold onto carbon on site and then ship the loaded carbon off-site to a toll refiner, which removes elution, acid-wash and electrowinning equipment from that project's own reagent-handling scope entirely. Others run a full on-site ADR circuit. Which configuration a given project uses is a real design decision, not something to assume from the ore body alone.
What reagents does a cyanide heap-leach ADR/carbon plant handle?
Sodium cyanide (the lixiviant) makeup and dosing on the barren-solution return; lime or caustic soda for pH control, since cyanide leaching requires an alkaline solution; hydrochloric or another dilute mineral acid for washing scale off loaded carbon ahead of elution, where a project runs on-site elution; and antiscalant dosing on the barren-solution recycle to protect piping, columns and any regeneration equipment from calcium carbonate scale.
What is antiscalant dosing used for in a heap-leach circuit?
Lime addition and ore contact bring dissolved calcium into the circulating solution. As barren solution recycles back to the heap, that calcium can precipitate as scale in piping, carbon columns, pumps and any heat-exchange or carbon-regeneration equipment. Antiscalant dosing, sized from the actual solution chemistry rather than pH alone, controls that scale buildup.
Sources. A 2025 NI 43-101 preliminary economic assessment (PEA) for a Nevada open-pit heap-leach gold-silver project (crushing capacity, cyanide/lime consumption, heap-leach pad design, ACA/CIC process description, water-right figures). Equipment and reagent-handling practice beyond the PEA's confirmed scope (elution, acid wash, electrowinning) is general industry practice for on-site ADR circuits, labeled as such above, not confirmed detail from this project. LibertyCES prepared this page independently from the public filing and is not affiliated with the project, its engineers or its ownership.
Specifying an ADR or Carbon Plant Reagent Package?
Send the flowsheet, reagent consumption figures and spec section. James Riggins will send back a matched cyanide, caustic, acid-wash and antiscalant dosing package.
(559) 395-5500 · james@libertyces.com · sales@libertyces.com