This page is where the individual recovery methods covered throughout this set, gravity, flotation, and leaching, come together into the single flowsheet a real tailings retreatment plant actually runs. Anyone who has read the gravity, flotation, and leaching pages separately should find this the page where those pieces click into a coherent whole, since no real Ghanaian tailings retreatment project relies on a single recovery method in isolation.
Why combine gravity and leaching rather than choosing one?
Combining gravity and leaching works because each method's blind spot is the other method's strength. Gravity recovers coarse, liberated gold cheaply and without reagent cost, described in full on gravity recovery of gold from tailings, but it cannot reach fine or surface-bound gold regardless of how well the equipment is specified. Leaching reaches gold at essentially any particle size, as long as the gold surface is exposed to reagent, but it costs money for every gram it dissolves, cyanide, oxygen, residence time, all scaling with tonnage processed. Running gravity first captures the cheap, easy fraction before it ever reaches the expensive chemistry, and the exact split between the two stages is set by the specific dump's GRG test result, not a fixed ratio applied uniformly across every project.
What does the gold balance look like across the two stages?
A well-run combined flowsheet typically shows gravity capturing a comparatively small tonnage of concentrate at very high grade, since gravity concentrates a small fraction of the total feed mass into a gold-rich product, while the leach circuit processes the much larger remaining tonnage at a lower unit value per tonne but across the bulk of the feed. Tracking recovery separately at each stage, rather than reporting only a single combined plant-wide figure, is what actually lets an operator or investor see whether each stage is performing at its tested capability, since a leach circuit compensating for an underperforming gravity stage can mask a problem that would otherwise be caught and corrected.
The relative split between the two stages is entirely dump-specific. A dump with coarse, well-liberated gold and a high GRG result will show gravity carrying a disproportionate share of total recovered ounces relative to the tonnage it processes, while a dump dominated by fine or sulphide-associated gold will show the leach circuit carrying most of the recovery burden even after a well-specified gravity stage has done everything it reasonably can. Neither pattern indicates a poorly designed flowsheet; both are the expected, testwork-predicted outcome for their respective dump types.
How does this flowsheet reduce reagent and capital cost compared to leach-only?
Every gram of gold the gravity stage captures is a gram the leach circuit never has to dissolve, which directly reduces cyanide consumption, residence time demand, and carbon inventory pressure on the leach circuit, the same logic already established on both carbon-in-leach (CIL) for tailings and cyanidation basics: chemistry of gold leaching. This is not a marginal saving; on a dump with a meaningful gravity-recoverable fraction, the leach circuit can be sized noticeably smaller, with lower ongoing reagent cost, than it would need to be if it were expected to handle the full contained gold on its own.
Where does flotation fit into this combined picture on sulphide-rich feed?
On sulphide-rich tailings, a third stage, flotation, is often inserted between gravity and leaching, described in full on flotation of gold tailings and sulphide flotation before leaching. Flotation concentrates the sulphide-associated gold gravity could not reach into a small, upgraded stream, letting the leach circuit treat that concentrated stream rather than the full gravity-tailings tonnage, extending the same mass-reduction economics gravity already applies at an earlier stage of the flowsheet.
What does a typical combined flowsheet look like in physical sequence?
A typical combined flowsheet begins with hydraulic re-mining and slurry pumping bringing tailings material to the plant, followed by trommel and scrubber feed preparation to size the material and break up clay cementation, then classification to separate the stream into size fractions suited to different downstream equipment. Gravity concentration follows, typically a spiral bank or centrifugal units, sometimes both in sequence, capturing the coarse, liberated fraction. Where testwork justifies it, flotation then concentrates sulphide-associated gold from the gravity tailings, and finally the leach circuit, CIL or CIP, dissolves gold from the flotation concentrate and, where economic, the remaining gravity and flotation tailings.
Each of these stages is covered in its own dedicated page elsewhere in this recovery methods and plant equipment set, and this sequence is precisely why those individual pages consistently link up to each other and to this synthesis page: no single stage tells the complete story of how a Ghanaian tailings retreatment plant actually processes material from dump to doré.
How does the economic logic actually compound across a real project?
Consider the reasoning stage by stage rather than as an abstract principle. Gravity capture at the front of the flowsheet removes coarse gold at minimal reagent cost, immediately lowering the tonnage-adjusted cyanide demand the leach circuit downstream would otherwise carry. Flotation, where sulphide content justifies it, then reduces the leach circuit's required tankage and residence time further by concentrating the remaining recoverable gold into a small fraction of the total mass. By the time material reaches the leach tanks, a well-designed combined flowsheet has already stripped out much of what would otherwise have been the most reagent-expensive material to treat directly.
This compounding effect is precisely why a feasibility study's capital and operating cost estimates should be built up stage by stage from real testwork data specific to the dump in question, rather than estimated from a single blended assumption about "the leach circuit's" cost. Two dumps with identical head grade but different GRG and sulphide content can have meaningfully different optimal flowsheets and correspondingly different capital requirements, even though a superficial grade comparison alone would suggest they are equivalent opportunities.
How does a project actually decide the right combination for its specific dump?
The right combination for a specific dump comes from a defined testwork sequence rather than a default assumption: GRG testwork establishes how much gold gravity alone can capture, particle size and liberation analysis shows whether any remaining gold is locked or simply fine, and diagnostic leach testwork confirms whether the remaining fraction responds to standard cyanidation or needs flotation, refractory pretreatment, or an alternative lixiviant first. Each of these testwork stages is covered in its own right in the metallurgy and testwork section of this site, and together they are what actually justify a specific flowsheet configuration for a real project rather than a generic industry template.
This sequence also has a natural order of operations worth stating explicitly: GRG testwork typically comes first, since it is comparatively quick and inexpensive and immediately tells a project how much weight its flowsheet should place on gravity. Particle size, liberation, and diagnostic leach testwork follow, refining the picture for whatever fraction gravity does not address. Only once this full sequence is complete does a flowsheet design genuinely rest on evidence rather than assumption, which is the standard this entire recovery methods set has been built around from its first page onward.
How the plant cluster embodies this flowsheet physically
The equipment sequence described on gold processing plants for tailings, from re-mining and feed preparation through gravity, optional flotation, and leaching, is the physical, built-out version of the flowsheet logic this page describes conceptually.
Why this staged approach also phases capital sensibly
A project can commission its gravity stage first, begin generating revenue from coarse gold recovery, and add flotation or expand leach capacity in a later phase once early operating data confirms the dump's actual recoverable grade, an approach that reduces early financing risk relative to committing to the full combined flowsheet's capital in a single phase.
Why an investor should expect to see this full sequence justified with real data
A feasibility study proposing a combined gravity-leach, or gravity-flotation-leach, flowsheet should show the GRG, liberation, and diagnostic leach results that justify each stage's inclusion and sizing, not merely assert the configuration as standard industry practice. This is the single most consequential technical decision in a tailings retreatment project's design, and it deserves the same scrutiny as the project's headline recovery and cost figures.
Why this synthesis page is the natural landing point after reading the individual method pages
Every recovery method and equipment page in this set, gravity concentrators, flotation cells, leach tanks, feed preparation equipment, and the testwork that sizes each of them, ultimately answers to the same question this page poses directly: how do these pieces combine into a single, coherent, testwork-justified flowsheet for a specific dump. Reading the individual pages builds the vocabulary; this page is where that vocabulary becomes a working mental model of an actual tailings retreatment plant.