Mining & Trade News

BULK SAMPLING IN MINERAL EXPLORATION

Why 10,000 Tonnes and Not Just a Few Kilograms?

An Article for the ward counselors,Chiefs and Communities

By:  Rajab Dulaja.

Economic Geologist - Mineral Exploration and Mining.

Graduated from Faculty of Minerals and Petroleum, International University of Africa - IUA, Sudan 

August 2026 | Lilongwe,

INTRODUCTION

In mining districts across Malawi, including Mangochi, one of the most common questions asked by ward counselors chiefs and communities.

Why does the company need to dig and take 10,000 tonnes of soil and rock? Can’t they just take 2 kilograms to test?

The answer lies in geology, engineering, and finance. While a few kilograms can tell us if mineral is present, 10,000 tonnes tells us if a mine can be built, if it will be profitable, and if it will benefit the community for 20 years. 

This article explains bulk sampling with real Malawi examples and a simple household example, and why it is a critical step before any large mine is approved under the Mines and Minerals Act 2023.

1. WHAT IS BULK SAMPLING?

Bulk Sampling is the extraction, transportation, and processing of a large quantity of ore — typically between 1,000 and 10,000 tonnes— for testing purposes. 

It is different from:

Grab Sampling: 1kg to 50kg picked by hand. Used in early exploration.

Drill Sampling: 10kg per meter from a drill rig. Used to estimate resources.

Bulk sampling is the bridge between _"we found minerals"_ and _"we can build a mine."_

Legal Requirement: Under the Mines Minerals Act 2023- any activity involving more than 1,000 tonnes for testing requires a Bulk Sampling Permit from the Minister. It is legally considered mining.

2. WHY NOT JUST A FEW KILOGRAMS? THE 5 CORE REASONS

1. Variability - "The Nugget Effect"Minerals are not evenly spread. 

Example: Gold in Namizimu Forest Reserve, Mangochi

5 samples of 2kg may show 24g/t average, but a 10,000t bulk sample reveals the true grade is 2g/t. 

Lesson: A few kilograms can lie. Ten thousand tonnes tells the truth.

2. Metallurgical Testing - "You Can’t Test a Factory with a Cup"

Example: Heavy Mineral Sands at Makanjira, Mangochi - MAWEI Mining

A 2kg test confirms titanium exists. But to know if machines clog, water usage, and recovery rate, the company must run 1,500 to 5,000 tonnes through a pilot plant for 30 days to design a $300 million plant correctly.

3. Bankable Data for Investors

No bank will lend $200 million based on 5kg. 

Example: Rare Earths at Songwe Hill, Phalombe - Mkango Resources

Bulk sampling 3,000 tonnes revealed recovery was 62% not 85%. This saved $150 million in plant redesign.

4. Real Mining Conditions & Dilution

Example: Limestone at Njeleza, Cement Products Ltd, Mangochi. 

Lab samples: 52% CaO. Bulk sample of 5,000t: 44% CaO due to waste rock mixed during blasting.

 5. Market Testing

Example: Zircon from Makanjira

Buyers in China require 25-75 tonnes to test before signing a contract for 1 million tonnes per year.

 HOUSEHOLD EXAMPLE: THE MAIZE FLOUR ANALOGY

To help chiefs and communities understand

Imagine,a 100g container of mixed powder: 

5g of Maize flour, 36g Salt, 59g Soil.

 You need to cook nsima for 10 people. You need 2.5kg of pure maize flour.

Question:

How much of the whole mixture must you process to get 2,500g of maize flour?

Calculation: 

2,500g ÷5g ×100g = 50,000g

= 50 tonnes of mixture

The Lesson: Just as you must process 50 tonnes of mixture to get 2.5kg of flour, a mining company must process 10,000 tonnes of rock to know the true grade. 

That’s BULK sampling. You test the bulk to know the truth.

3- ROLE OF THE DISTRICT MINING OFFICER

Because bulk sampling is large-scale, the DMO has 6 responsibilities:

1.  Verify the Permit: Confirm Bulk Sampling Permit from the Minister

2.  Monitor Tonnage: Use weighbridge to ensure only approved tonnage is moved

3.  Collect Revenue: Ensure royalty is paid. Heavy minerals = 10% of gross value

4.  Environmental Compliance: Check dust, pit safety, rehabilitation. Critical for Lake Malawi

5.  Community Engagement: Ensure CDA 2021 is signed. Communities benefit during sampling

6.  Reporting: Submit final reports to MMRA on tonnage, grade, and destination

Note: 1-The company needs 10,000 tonnes to test if the the ore can be mined and processed profitably for not less than 15 years.

2- Poor monitoring of bulk sampling contributes to Malawi losing an estimated MK20 million per day to illegal mining.

TABLE 1:MAIZE FLOUR ANALOGY-HOUSEHOLD-

Lesson: Few kilograms tells if the maize flour exists in the mixture. 50 tonnes tells us if we can feed 10 people.

TABLE 2:THE RARE EARTHS ORE ANALOGY-GEOLOGY-

Lesson: Few kilograms are for testing mineral presence. Thousand tonnes are for decisions.

By Law: Any company extracting and exporting more than 1,000 tonnes must have a Bulk Sampling Permit from MMRA/ Minister of Mining. [Mines and Minerals Act 2023].

 WHY SO MUCH SAMPLE? THE MAIZE FLOUR EXAMPLE

To cook nsima for 10 people, you need 2.5kg of pure maize flour.

But what if your maize flour mixed with soil and other things?

If 100g of mixture only has 5g of maize flour....

To get 2.5kg of maize, you must process 50 TONNES of mixture.

Mining is the same. To find 2.5kg of economic mineral, they must test atleast 10,000 tonnes of rock. The rest are regarded as wastes (Gangue minerals).

4- KEY BENEFITS OF BULK SAMPLING

1.  Jobs: 30-100 people employed during sampling

2.  Revenue: Government collects royalty even during testing

3.  Truth: Proves if the mine will really bring schools, clinics, and roads

5-WHY ARE SAMPLES TAKEN OUTSIDE MALAWI FOR TESTING?

What Are We Lacking?

This is another most common question from communities: _"Why is our soil going to South Africa, Australia or China?"_

The answer is the same reason we refer patients from Mangochi District Hospital to South Africa or India.

Health Example:

A patient needing brain surgery or cancer treatment is referred abroad. 

Why?Lack of specialized doctors, lack of MRI and radiotherapy machines, lack of specialized labs. 

The goal is to save the patient's life with the best and most trusted treatment.

Mining Example: 

We send 50kg of rock to Johannesburg, China or Australia...

The 4 Main Reasons:

 1-Lack of Specialized Laboratories.

Testing rare earths, zircon, and heavy minerals requires machines costing $2M - $10M. Examples: ICP-MS, Pilot flotation plants, Radioactivity testing. 

Malawi currently has basic labs at MMRA and universities, but not pilot-scale plants._

2-Bankable Certification

Banks and buyers in London, Toronto, and Shanghai only trust results from labs certified by ISO 17025. Most of these labs are in South Africa, Australia, Canada. 

 Without this certificate, no one will invest $200 million.

3-Metallurgical Testing at Scale

To test 5,000 tonnes you need a pilot plant. Malawi does not yet have commercial pilot plants for rare earths or heavy minerals.

4-Speed and Cost

 Sending 50kg by air to Johannesburg and getting results in 3 weeks is faster and cheaper than building a new lab that will take long time. However, while sending samples outside Malawi, government has to source funds to build local laboratory in the near future.

5-To Protect Malawi’s Interest: Bad metallurgical data leads to a failed mine. A failed mine means no royalties, no jobs, and an abandoned pit. Bulk testing abroad protects us from that risk

What Should We Do? - 3 Recommendations

1. Short Term: Negotiate with companies that a % of samples must be tested at MMRA labs in Lilongwe for verification.

2.  Medium Term: Build a Regional Pilot Plant Hub.

3.  Long Term: Through the Mines and Minerals Act 2023,require companies to do "progressive in-country testing" as part of their Bulk Sampling Permit conditions.

Note: The DMO must record where samples are sent, by whom, and ensure MMRA gets duplicate results.

6-  ROLE OF THE DISTRICT MINING OFFICER

Track Sample Export: Keep a register of all samples exported. Ensure MMRA export permits

CONCLUSION:

Bulk sampling is a critical bridge between exploration and full-scale mining. It allows a license holder to extract and process a large volume of ore to confirm grade, metallurgy, and economic viability before committing millions of dollars to develop a mine.

However, under the Mines and Minerals Act 2023,bulk sampling is no longer an informal "test" activity. It must be done transparently, with an approved Work Program, ESIA clearance, notification to the District Council, and full reporting to MMRA. Where ore is sold during bulk sampling, royalty at 3-15% is payable, closing the loophole that contributed to revenue losses highlighted in the 2024 Auditor General’s report.

From a regulatory perspective, bulk sampling presents both an opportunity and a risk. The opportunity is that it reduces investment risk and attracts serious investors, which aligns with MMRA’s mandate to promote responsible mining. The risk is that it can be abused for illegal mining and mineral smuggling if not monitored. This is why the 2023 Act imposes strict penalties of up to K5,000,000 fine or 3 years imprisonment for unauthorized bulk sampling.

The role of District Mining Officer, is to ensure that all bulk sampling in the district is compliant: by  verifying the work program, confirm EPA approval, ensure community engagement through CDAs, and that all production data and royalties are reported. This protects government revenue, the environment, and community interests.

In summary, bulk sampling must be treated as part of the mining cycle, not separate from it. When properly regulated, it supports value addition, job creation, and increased government revenue— which are the core objectives of the Mines and Minerals Act 2023.

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