Metal Equivalent Grade
Compute the metal equivalent grade of a polymetallic ore by adding to the main metal's grade the contribution of secondary metals weighted by the price ratio: Eq = main_grade + secondary_grade · (price_sec/price_main). It converts a deposit with several metals (e.g. copper with gold and silver) into a single comparable grade, used to set the cutoff grade and evaluate the deposit. Enter the main grade, the secondary grade and the price factor (price_sec/price_main).
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Metal equivalent grade
Many ore deposits carry several metals at once — copper with gold and silver, zinc with lead. How can such a deposit be compared and valued with a single number? Through the equivalent grade: the contribution of the secondary metals is converted into an 'equivalent' of the main one, weighted by relative value: Geq = main_grade + secondary_grade·(price_sec/price_main). A copper ore that also carries gold thus becomes a 'copper equivalent' grade that bakes in the gold bonus. This unified number is used to set the cutoff grade, compare blocks in the resource model and classify the reserves. The caveat is that it depends on the prices and the recoveries of each metal, which change over time. Enter the main grade, the secondary grade and the price factor.
Related Tools
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.
Mineral Reserve Tonnage
Compute a mineral reserve's tonnage, T = Volume · Density, multiplying the ore body volume (m³) by the rock bulk density (t/m³). It is the step that turns the estimated geometry of a deposit (from drilling and modeling) into ore mass — the basis of any economic evaluation of a deposit. Enter the volume and the ore density.
Metallostatic Pressure
Calculate the metallostatic pressure exerted by molten metal at the bottom of a mold, P = ρ × g × h, from the molten metal density ρ (kg/m³), gravity g and the metal column height h (m). The result, in pascals, is the pressure the molten metal exerts on the mold walls and bottom due to its own weight — analogous to hydrostatic pressure, but with the high density of metals. It is essential to size the mold strength (which can 'burst' or deform under pressure), predict core flotation and metal penetration into gaps. Dense metals (iron, ~7000 kg/m³) generate high pressures. Enter the metal density and the column height.
Cutoff by Percentile Calculator
Given a set of scores and a cutoff percentile (e.g., top 10%), compute the minimum score to make the cut. Useful for college admissions, HR.
Grinding Energy (Bond Work Index)
Calculate the specific comminution (grinding/crushing) energy by Bond's law, W = 10 × Wi × (1/√P₈₀ − 1/√F₈₀), from the ore's Bond work index Wi (kWh/t), and the particle sizes passing 80% of the product (P₈₀) and feed (F₈₀), in micrometers. The result, in kWh per tonne, is the energy needed to reduce the ore from feed to product size. Comminution is mining's largest energy consumer (up to 50% of the plant). The Wi index characterizes the ore's resistance to fragmentation. It is the basis for sizing mills and energy consumption. Enter the Wi, P₈₀ and F₈₀.
Machining Spindle Speed
Calculate the spindle speed (RPM) needed in machining, n = (1000·Vc) ÷ (π·D), from the desired cutting speed Vc (m/min) and the diameter D (mm — workpiece in turning or tool in milling). It is the inverse of the cutting-speed calculation, and the most used on the shop floor: the operator knows the material, picks the recommended cutting speed from tables, and must convert it to the rpm to set on the machine. The relation reveals a key point: for the same cutting speed, SMALLER-diameter parts or tools require HIGHER rpm (and vice versa). So turning a part of varying diameter (facing, tapers) at constant cutting speed requires continuously varying the rpm — done automatically by CNC lathes (G96, constant surface speed), while on conventional lathes the operator adjusts by ranges. Getting rpm right is essential for tool life, finish and safety (excessive rpm on large parts creates dangerous centrifugal forces). Enter the cutting speed and the diameter.
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.