Stripping Ratio (SR)
Compute the stripping ratio (SR) of an open-pit mine by dividing the amount of waste (worthless rock that must be removed) by the ore extracted. It is the central economic indicator of open-pit mining: the higher the SR, the more useless material is moved per tonne of ore, and the higher the cost. It defines the pit limit and the viability of the operation. Enter the waste and ore quantities.
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Razão estéril/minério (REM)
Numa mina a céu aberto, para chegar ao minério é preciso remover a 'capa' de rocha sem valor que o cobre — o estéril. A REM (razão estéril/minério, ou strip ratio) mede esse esforço: quantas toneladas de estéril são removidas para cada tonelada de minério lavrada. É um dos números que mais pesam na economia da mina: cada tonelada de estéril precisa ser perfurada, detonada, carregada e transportada ao bota-fora, sem gerar receita. A REM cresce à medida que a cava aprofunda, e o ponto em que ela torna a lavra inviável define o limite econômico de cava. Acima de certa REM, compensa mudar para lavra subterrânea. Informe as quantidades de estéril e de minério.
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Ore Dilution
Compute ore dilution in mining, D = waste/(ore + waste)·100%, the proportion of waste that ends up mixed with the ore during extraction, lowering the grade reaching the plant. Every operation has some dilution (irregular contacts, imprecise blasting); controlling it is essential, since diluted ore consumes energy and reagents to process worthless material. Enter the masses of diluting waste and ore.
Tail Ratio
Computes the tail ratio of a return series: the absolute value of the 95th percentile divided by that of the 5th percentile. It compares the size of extreme gains with extreme losses — a tail ratio above one means the right tail (gains) is larger than the left (losses), a desirable asymmetric profile. Below one, extreme losses dominate. It's a quick snapshot of the asymmetry at the ends of the distribution. Enter the list of returns separated by commas.
Total Reduction Ratio
Calculate the total reduction ratio of a three-stage comminution circuit, RR_total = RR₁ × RR₂ × RR₃, multiplying the reduction ratios of each crusher/mill in series. The dimensionless result is the circuit's overall size reduction — from bench rock blocks (hundreds of mm) to fine particles (mm or µm). Since each stage has a limited reduction ratio (4 to 10 for crushers), large total reductions (100, 1000 or more) require several stages in series: primary, secondary, tertiary crushing and milling. Enter the reduction ratios of the three stages.
The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.