Core Trays: Key Differences Between HQ, PQ, NMLC, and Sonic

When it comes to geotechnical and mineral exploration, core sampling is a vital part of gathering data from beneath the surface. Core trays play a crucial role in the storage, handling, and transportation of core samples. But with various core sizes and drilling methods available—like HQ, PQ, NMLC, and Sonic—understanding the key differences is essential for selecting the right tools for your project.

In this blog, we’ll break down the characteristics of core trays and explain the distinctions between HQ, PQ, NMLC, and Sonic core sampling methods.

What Are Core Trays?

Core trays are specifically designed containers used to store, organize, and protect core samples during transportation and analysis. These trays are essential for keeping core samples intact, preserving the integrity of the material collected, and ensuring they are easily accessible for further examination.

Core trays are typically made from a variety of materials, depending on the specific needs of the project and the type of core sample being handled, with standard tray designs featuring multiple rows to hold individual core segments. The size of the core tray is often matched with the core drilling method used to ensure an efficient fit.

Core Tray Sizes and Their Applications

Core tray sizes vary based on the drilling method used to collect the core sample. Let's dive into the differences between the main core sampling methods and their corresponding tray sizes.

1. NMLC Core Trays

  • Core Diameter: 50.6 mm (nominal size)
  • Common Uses: NMLC core trays are ideal for storing smaller core samples collected during geological or geotechnical investigations. The relatively smaller diameter makes them suitable for detailed analysis of softer materials.
  • Key Features: NMLC trays are compact, often with a 4-row design, making them perfect for storing smaller core samples without wasting space. They are ideal for projects requiring detailed study where large sample sizes are not necessary.

2. HQ Core Trays

  • Core Diameter: 63.5 mm
  • Common Uses: HQ core trays are commonly used in mid-range geotechnical investigations and resource evaluations. With a slightly larger core diameter, HQ trays provide more substantial sample sizes, making them suitable for a wide variety of applications in exploration and environmental sampling.
  • Key Features: The 63.5 mm diameter allows for an excellent balance between detailed analysis and material recovery. HQ core trays are typically used for projects where sample quality and recovery are key, but large core samples are not required.

3. PQ Core Trays

  • Core Diameter: 85 mm
  • Common Uses: PQ core trays are the go-to choice for mineral exploration, resource drilling, and projects where bulk sample recovery is important. The larger core diameter ensures that substantial amounts of material can be recovered, allowing for accurate assessments of mineral deposits or geotechnical properties.
  • Key Features: Due to their larger diameter, PQ core trays are capable of holding more material, making them ideal for applications that require larger, more substantial samples. This size is essential when high recovery rates are necessary to gain a better understanding of the subsurface material.

4. Sonic Core Sampling

  • Core Diameter: Varies (typically larger than PQ)
  • Common Uses: Sonic core trays are used in a different drilling method entirely—sonic drilling. This technique uses high-frequency vibrations combined with rotation to obtain core samples from the subsurface. Sonic core sampling is especially effective for recovering undisturbed samples from soft or unconsolidated materials, such as sands, silts, and clays.
  • Key Features: Sonic drilling produces core samples that are highly preserved, making them ideal for environmental and geotechnical investigations. The trays used for sonic samples can accommodate cores similar to or larger than those from PQ drilling, ensuring that the 'undisturbed' sample quality is preserved during storage and transportation.

Key Differences Between HQ, PQ, NMLC, and Sonic Core Sampling Methods

1. Core Size and Recovery:

  • NMLC provides smaller core samples, ideal for detailed but compact geological analysis.
  • HQ offers a medium-sized core, balancing sample detail and recovery.
  • PQ provides the largest core samples, used for mineral exploration and when high recovery rates are needed.
  • Sonic drilling allows for undisturbed core samples, particularly useful in unconsolidated or soft materials, and the core size can vary.

2. Applications:

  • NMLC is commonly used in geological studies and geotechnical investigations where a smaller core diameter is sufficient.
  • HQ is versatile for geotechnical and environmental applications that require a balanced approach between sample recovery and material analysis.
  • PQ is favored for mineral exploration, where larger sample sizes are required for accurate resource evaluation.
  • Sonic drilling is ideal for environmental sampling and geotechnical work in unconsolidated soils, as it preserves core integrity better than traditional methods.

3. Efficiency:

  • NMLC and HQ methods are generally more cost-effective for smaller-scale drilling projects.
  • PQ methods are more expensive but offer better recovery and larger sample sizes.
  • Sonic drilling is highly efficient in certain conditions but can be costlier due to the specialized equipment and technique involved.

Conclusion: Selecting the Right Core Tray for Your Drilling Project

Understanding the differences between HQ, PQ, NMLC, and Sonic core sampling methods is key to choosing the right core tray and drilling method for your project. Each method has its specific advantages, and selecting the appropriate core size and sampling technique can significantly impact the quality and accuracy of the data you collect.

At SiSupply, we offer a wide range of core trays tailored to various core sampling methods, ensuring you have the best solution for your geotechnical, environmental, and mineral exploration needs. Our core trays are designed for durability and efficiency, offering secure storage and handling of your valuable core samples.

If you need assistance selecting the right core tray for your project, feel free to contact us—we’re here to help!

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