Large Low Grade Copper-Gold Deposits: How Low Can …

Cut-off grade is perhaps the simplest way to understand the economics of large, low grade mining operations. This is the grade above which a particular mine is profitable. Freeport-McMoRan Copper & Gold Inc. is the world's largest, listed copper producer. It has operations in the America's, Indonesia and Africa. It also happens to mine some of the lowest copper grades in the world.

Decreasing Ore Grades in Global Metallic Mining: A ...

Resources 2016, 5, 36 3 of 14 grades for zinc mines, the average ore grade in the mine (xm) estimated by Cox and Singer [29] is 6.05% Pb + Zn. There are also complementary studies regarding the ore grade of specific countries [30].

Grade Tonnage Curve: How Far Can It Be Relied Upon?

face of variations of the cut-off grade. The grade tonnage curve is usually calculated with the in-situ resources or reserves and shows always the 'best' or 'optimistic' scenario, i.e., at a given cut-off grade …

Types of Copper Deposits in the World | Investing News …

The average grade of copper ores in the 21st century is below 0.6 percent copper, with the proportion of ore minerals being less than 2 percent of the total volume of the ore rock. Learn to profit ...

Part Four Competitiveness - Princeton University

Part Four Competitiveness ... change the cut-off grade (the lowest grade that is mined and treated). These are very important decisions in the operation of a mining project. They must be considered in the context of the prevailing copper price, the health of the firm, and the mine plan. Such actions ultimately affect the overall output of the mine and are therefore not undertaken capriciously ...

Cut-off grade determination for the maximum value of a ...

g– is the average grade of the ore above cut-off. In the limiting cases the following formulae apply for mining: for processing and for marketing Note the last two terms for the processing and marketing equations are identical in form and in each case the cut-off grade will fall as F declines because the remaining life of the mine is reduced. None of the formula makes direct reference to the ...

100 Years of Resource Growth for Copper - Impact of …

100 Years of Resource Growth for Copper - Impact of Costs, Grade and Technology 11,957 views. Share; Like ; Download ... This allowed companies to lower their cut-off grade – thereby expanding the available resource by a factor of six. The author argues that engineers and geologists acted as equal partners in growing the resource base over the last Century. Assuming that we continue to ...

Copper extraction - Wikipedia

The average grade of copper ores in the 21st century is below 0.6% copper, with a proportion of economic ore minerals (including copper) being less than 2% of the total volume of the ore rock. A key objective in the metallurgical treatment of any ore is the separation of ore …

Cutoff grade - Wikipedia

Cut-Off grade is the minimum grade required in order for a mineral or metal to be economically mined (or processed). Material found to be above this grade is considered to be ore, while material below this grade is considered to be waste.

Determination of optimum cutoff grades of multiple metal ...

The Journal of The South African Institute of Mining and Metallurgy OCTOBER 2003 493 Introduction In open pit mines, cutoff grade is used to discriminate ore from waste.

Mining Cutoff Grades | Aussie Stock Forums

2006-05-12· As the prevailing metal prices rise, the cost of extracing metals from lower grade ore bodies becomes less of an issue. As a result, copper mines that were once too expensive are now being opened up, while nickel ore bodies that would never be touched at …

Break-Even Analysis - How to Calculate the Cut-Off …

This article about how to calculate the cut off grade is a great resource for investors in individual mining stocks. However, when you are investing in mining stocks through a Stock Based mineral ETF I recommend you to read this article too.

Mining Valuation Lesson: Cut-Off Grade Theory And …

Cut-off Grade Theory and Practice Consider a block of ore that weighs 1 tonne and contains 3 grams of gold. At a gold price of US$1000 per ounce the value of the gold in the block of ore is just ...

The world's top 10 highest-grade copper mines | …

While the copper market is gaining momentum, it is a good time to look at the copper mining champions in terms of copper grade in ore reserves.

Cut-off grade estimation - QueensMineDesignWiki

For conducting a mining project's break even analysis, you first need to know about the operational expenses (OPEX). When the OPEX is known, you can calculate the mineral's cut off grade, which is the break even grade, below which it is not economically viable to mine the ore.

(PDF) A Cut-Off Grade Economic Strategy for a By-Product ...

This article reviews the influence of the ore grade-tonnage distribution over the cut-off grade policy in a given mining operation. In this study, firstly, the interpolation parameters used to ...

2007 MINERAL RESOURCE & ORE RESERVE EXPLANTATORY NOTES

Cut-off grade calculations assume metal prices of $600 per ounce of gold and $1.60 per pound of copper with the exception of Kencana where USD $550 per ounce of gold is assumed. Mineral Resources, where

Mine cutoff grade | Britannica.com

This is called the mine cutoff grade. And, if the material has already been mined, there is a certain grade below which it is not profitable to process it; this is the mill cutoff grade. The grade at which the costs associated with mining and mineral processing just equal

mining part ii - d32ogoqmya1dw8.cloudfront.net

The cut-off grade of an ore is essentially the lowest grade of an ore that is worth mining. If the ore grade If the ore grade is less than the cut-off grade, then a mining company will not make money mining that ore.

Making the grade: understanding exploration results ...

As a rule of thumb, open pit mining can process ore for $10 per tonne and, where the ore grade is more than double that at $20 per tonne, results would be economic. Consider that 1% of a metric ...

Mining Valuation Lesson: Cut-Off Grade Theory and …

If you increase the cut-off grade, you decrease the life of the mine due to diminishing reserves (reserves are ore in a deposit that is economical to extract, see Mining 101: It's Not that Simple), but you would increase gold production due to the higher grade.

12.3 Primary Copper Smelting

12.3 Primary Copper Smelting 12.3.1 General1 Copper ore is produced in 13 states. In 1989, Arizona produced 60 percent of the total U. S. ore. Fourteen domestic mines accounted for more than 95 percent of the 1.45 megagrams (Mg)

Using equivalent grade factors to find the optimum cut …

To do this, tonnage of ore in first year of mine life from the grade distribution intervals above optimum cut-off grades and tonnage of waste in first year of mine life from the grade distribution intervals below optimum cut-off grades was subtracted. These calculations are repeated until the end of mine life.

Some observations on copper yields and ore grades ...

Introduction. There is a general presumption that the average percentage copper content of ores mined has steadily declined over the years. The higher grade …

Part Three Resources and Technology - Princeton University

Chapter 5 World Copper Resources A copper ore deposit is a localized zone in the earth's crust that contains copper-bearing min-erals in unusually large quantities.

Cut-Off Grades For Mineral Resource Reporting | SRK

A cut-off grade (COG) is an industry-accepted standard expression used to determine what part of a mineral deposit to include in a mineral resource estimate (MRE). For MRE reporting, COGs tend to be rounded down to ensure that material of no economic significance is excluded from the resource.