Conglomerado

Tipo
Sedimentary rock (clastic)

Composição
Rounded clasts (pebbles, cobbles) + matrix (sand, silt, clay)

Common Minerals
Gold (Au), diamonds (C), cassiterite (SnO₂), ilmenite (FeTiO₃), quartz (SiO₂)

Classificação de minerais
Polymictic (mixed clasts) / Oligomictic (single dominant clast)

Hardness (Mohs)
Variable (4–7, depends on clasts: quartz = 7, gold = 2.5–3)

Grain Size
Clasts: >2 mm (pebbles to boulders); Matrix: sand/silt (<2 mm)

Cor
Multicolored (clast-dependent), often gray, brown, or reddish

Brilho
Clasts: vitreous (quartz), metallic (gold); Matrix: dull

Fratura
Irregular (clasts may break conchoidally)

The conglomerate is a sedimentary rock made of rounded pebbles and sand that is usually held together (cemented) by silica, calcite, or iron oxide. It is a stone similar to sandstone, but the rock particles are rounded or angular gravel rather than sand.

O conglomerado é uma rocha de grão grosso que se forma frequentemente nos leitos dos rios. Os seixos e a areia podem ser compostos por muitos minerais diferentes, mas geralmente são minerais à base de quartzo.

O conglomerado tem uma dureza variável e parece-se frequentemente com betão. Encontra-se geralmente em camadas grossas e grosseiramente estratificadas. Os leitos de conglomerado são frequentemente reservatórios subterrâneos de água e petróleo. Os conglomerados são utilizados na indústria da construção como pedra decorativa.

Conglomerates (sedimentary rocks with rounded clasts in a finer matrix) often host gold, diamonds, tin, or heavy minerals (e.g., zircon, rutile). Their processing depends on ore type, grain size, and liberation characteristics.

1.Crushing & Scrubbing (Deagglomeration)

• Trituração grosseira (Jaw → Cone crusher) if clasts are >50 mm.
• Rotary scrubbers ou depuradores de atrito remove clay and break loosely cemented matrix.
  → Prevents “slime blinding” in later gravity separation.

2. Screening & Classification

• Trommel screens separate oversized waste (+50 mm).
• Hydrocyclones ou peneiras vibratórias classify finer fractions for gravity concentration.

3. Gravity Separation (Primary Method)

1. Gabaritos (for coarse gold/heavy minerals).
2. Concentradores em espiral (for medium sand-sized particles).
3. Mesas de agitação (for fine gold/mixed concentrates).
4. Concentradores centrífugos (Knelson/Falcon – high recovery of micron gold).

✓ Best for: Alluvial-type conglomerates (e.g., Witwatersrand gold, Namibian diamonds).

4. Flotation or Leaching (If Needed)

• Flotação: Useful for sulfide minerals in the matrix (e.g., pyrite-associated gold).
• Cyanidation (CIL/CIP): If gold is liberated but too fine for gravity.
• Dense Media Separation (DMS): For diamond/tin-bearing conglomerates (using ferrosilicon slurry).

5. Tailings Management & Final Recovery

• Slime treatment: If the clay content is high, use thickeners or filter presses.
• Re-processing: Scavenger circuits (e.g., secondary centrifugal concentrators).