Mining for the Electric Revolution Minerals

What’s the typical proportion between the overburden, the ore and the useful substance for spodumene?

ChatGPT said:

ChatGPT

In spodumene mining, the typical proportions between overburden, ore, and the useful substance (which is lithium-bearing spodumene) can vary significantly depending on the deposit and the mining method. Here’s a general breakdown:

1. Overburden:
   • This is the waste rock or soil that lies above the ore body. In open-pit spodumene mining, overburden can be significant, typically constituting a large portion of the material to be removed to access the ore. The overburden-to-ore ratio (also called the stripping ratio) can vary widely but often ranges between 1:1 to 5:1. This means for every ton of ore, 1 to 5 tons of overburden might need to be removed, though it could be higher in some cases.
2. Ore:
   • The ore consists of the rock containing spodumene crystals, from which lithium can be extracted. Not all the material in the ore is useful spodumene; it also contains other minerals, which are considered gangue or waste rock in this context. The grade of spodumene in the ore varies, typically between 1-3% Li₂O (lithium oxide content).
3. Useful Substance (Lithium-bearing spodumene):
   • The lithium content in spodumene varies but is usually expressed as a percentage of lithium oxide (Li₂O). High-quality spodumene deposits have concentrations of around 6-7% Li₂O in the pure mineral, but the actual concentration in the mined ore is lower due to the presence of other minerals. The beneficiation process (crushing, grinding, flotation, etc.) is required to increase the concentration of lithium from the ore.

To summarize, a typical spodumene mining operation might have an overburden to ore ratio of 1:1 to 5:1, and within the ore, spodumene might be concentrated to about 1-3% lithium oxide. After processing, this concentration can be increased to around 6-7% Li₂O.

4o

You said:

What’s the typical proportion between the overburden, the ore and the useful substance for cobalt?

ChatGPT said:

ChatGPT

In cobalt mining, the proportions between overburden, ore, and the useful substance (cobalt) vary depending on the type of deposit, mining method, and location. Here’s a general breakdown:

1. Overburden:

• Overburden consists of the material (soil, rock) above the ore body that needs to be removed to access the ore. In open-pit cobalt mines, the overburden can be substantial. The overburden-to-ore ratio (stripping ratio) can range from 1:1 to 10:1, depending on the depth and type of the deposit. Higher stripping ratios are common in large-scale open-pit operations, particularly in regions like the Democratic Republic of Congo (DRC).

2. Ore:

• Cobalt is often mined as a byproduct of copper or nickel mining, and the ore body typically contains a mixture of minerals. In cobalt-copper deposits (like those in the DRC), the cobalt content in the ore is relatively low, often between 0.1-1% cobalt by weight. In cobalt-nickel deposits (such as those found in Canada, Australia, and Russia), the cobalt content in the ore can also be low, typically between 0.05-1.5% cobalt.

3. Useful Substance (Cobalt):

• The actual cobalt extracted from the ore is usually in the form of cobalt sulfides or oxides. The ore is processed to extract the cobalt, which involves techniques like flotation, smelting, and hydrometallurgical processes to separate and concentrate the cobalt.
• After processing, cobalt concentrations can be increased to 20-40% cobalt concentrate, depending on the method and the nature of the deposit.

Example Proportions (for Open-Pit Mining):

• Overburden: Could range from 1-10 tons of overburden for each ton of ore mined.
• Ore: Contains around 0.1-1.5% cobalt by weight, meaning 1 ton of ore might yield 1 to 15 kg of cobalt.
• Cobalt: After processing, the cobalt concentrate is extracted from the ore, and further refining increases purity.

In underground cobalt mining, the overburden ratio might be lower, but accessing the ore can be more challenging and costly.

Let me know if you’d like specific examples from different regions or mining operations!

4o

You said:

What’s the typical proportion between the overburden, the ore and the useful substance for copper?

ChatGPT said:

ChatGPT

In copper mining, the proportions between overburden, ore, and the useful substance (copper) can vary widely based on the deposit type, the mining method, and the ore grade. Below is a general breakdown:

1. Overburden:

• Overburden refers to the waste material (rock, soil) lying above the ore body that must be removed to access the ore. In open-pit mining, the stripping ratio (overburden-to-ore ratio) can vary significantly, often ranging from 0.5:1 to 3:1, meaning that for every ton of ore mined, between 0.5 and 3 tons of overburden might need to be removed. In some extreme cases, the stripping ratio can be even higher.

2. Ore:

• Copper ore contains a mix of copper minerals and gangue (waste rock). The concentration of copper in the ore is typically quite low, often in the range of 0.5% to 2% copper by weight, although some high-grade deposits can exceed 2%.
• The most common copper ores include chalcopyrite (CuFeS₂), which contains around 34.5% copper in its pure form, but the actual copper content in mined ore is much lower.

3. Useful Substance (Copper):

• After mining, the ore is processed to concentrate the copper. The processing involves crushing, grinding, flotation, and smelting to separate the copper from the ore.
• In modern operations, the concentrate typically contains between 20-30% copper, depending on the efficiency of the processing and the nature of the ore.
• Further refining (such as electrolysis) is needed to produce pure copper metal, which is usually 99.9% pure.

Example Proportions (for Open-Pit Copper Mining):

• Overburden: The overburden-to-ore ratio is often between 0.5:1 to 3:1, meaning that 0.5 to 3 tons of overburden may need to be removed for every ton of ore mined.
• Ore: The copper content in the ore is typically around 0.5-2% copper, so 1 ton of ore might yield 5 to 20 kg of copper.
• Copper Concentrate: After processing, the copper concentrate might contain 20-30% copper, meaning 1 ton of concentrate contains 200 to 300 kg of copper.

In underground mining, the overburden is often lower, but the operational costs and extraction challenges can increase.

Regional Variations:

• Porphyry Copper Deposits (such as those found in Chile, Peru, and the U.S.) usually have low grades of copper, typically around 0.5-1% copper in the ore, but are mined in massive quantities.
• Sediment-hosted Copper Deposits (e.g., in Zambia and the DRC) often have slightly higher grades, sometimes approaching 2% copper.

Let me know if you’d like more specific data on certain types of copper deposits!

4o

You said:

What’s the typical proportion between the overburden, the ore and the useful substance for Nickel?

ChatGPT said:

ChatGPT

In nickel mining, the proportions between overburden, ore, and the useful substance (nickel) depend on the type of deposit, the mining method, and the ore grade. Nickel is typically extracted from two main types of deposits: laterite and sulfide ores. These deposit types have different characteristics, which influence the overburden, ore, and nickel proportions. Here’s a general breakdown:

1. Overburden:

• Overburden is the material (rock, soil) covering the ore body that needs to be removed to access the ore. In open-pit mining of nickel deposits, the overburden-to-ore (stripping) ratio can vary widely depending on the depth and characteristics of the deposit.
• For laterite deposits (near the surface in tropical regions), the stripping ratio is usually lower, typically ranging from 1:1 to 5:1. This means for every ton of ore, between 1 and 5 tons of overburden must be removed.
• In sulfide deposits (often found in deeper, underground settings), the stripping ratio can be higher if open-pit mining is used, but in underground mining, the overburden might be less significant.

2. Ore:

• The ore contains a mix of nickel-bearing minerals and gangue (waste material). The grade of nickel in the ore depends on whether it’s a laterite or sulfide deposit:
  • Laterite ores typically contain between 0.8-1.5% nickel.
  • Sulfide ores usually have higher nickel concentrations, typically in the range of 1-3% nickel, though some high-grade deposits can exceed 3%.

The ore is processed to concentrate the nickel, with the proportion of nickel being relatively low in the ore before beneficiation.

3. Useful Substance (Nickel):

• After processing, the nickel content is increased significantly. Nickel ore undergoes a variety of processes, including crushing, flotation, smelting, and refining to increase the nickel concentration.
• After beneficiation, the nickel concentrate can contain 10-20% nickel, depending on the processing method and ore type. For laterite ores, hydrometallurgical techniques (such as high-pressure acid leaching) are often used, while sulfide ores typically undergo pyrometallurgical processes like smelting.

Example Proportions (for Open-Pit Nickel Mining):

• Overburden: The overburden-to-ore ratio in open-pit nickel mining is typically between 1:1 and 5:1, meaning 1 to 5 tons of overburden are removed for each ton of ore mined.
• Ore: The nickel content in the ore is generally 0.8-3% nickel (depending on whether it’s a laterite or sulfide deposit).
• Nickel Concentrate: After processing, nickel can be concentrated to 10-20% nickel content in the product.

Regional and Deposit Variations:

• Laterite Deposits: Found in tropical regions (e.g., Indonesia, the Philippines, New Caledonia), where laterite ores are mined near the surface, resulting in lower stripping ratios.
• Sulfide Deposits: Found in areas such as Russia, Canada, and Australia. These deposits are often deeper, especially when underground mining methods are used, and can have higher nickel grades.

Let me know if you’d like details about a specific type of nickel deposit or location!