The image above represents rock quality designation.

To compute for rock quality designation, two essential parameters are needed and these parameters are **Sum of the Length of Core Pieces > 10cm (S) **and **Total Length Drilled or Core Recovery (L). **

The formula for calculating the rock quality designation:

RQD = 100(^{S} / _{L})

Where:

RQD = Rock Quality Designation

S = Sum of the Length of Core Pieces > 10cm

L = Total Length Drilled or Core Recovery

Let’s solve an example;

Calculate the rock quality designation? Given that the sum of the length of core pieces > 10cm is 20 and the total length drilled or core recovery is 14.

This implies that;

S = Sum of the Length of Core Pieces > 10cm = 20

L = Total Length Drilled or Core Recovery = 14

RQD = 100(^{S} / _{L})

RQD = 100(^{20} / _{14})

RQD = 100(1.428)

RQD = 142.85

Therefore, the **rock quality designation **is **142.85.**

**Calculating the Sum of the Length of Core Pieces > 10cm when the Rock Quality Designation and the Total Length Drilled or Core Recovery is Given.**

S = RQD x L

Where:

S = Sum of the Length of Core Pieces > 10cm

RQD = Rock Quality Designation

L = Total Length Drilled or Core Recovery

Let’s solve an example;

Calculate the sum of the length of core pieces > 10cm? Given that the rock quality designation is 32 and the total length drilled or core recovery is 11.

This implies that;

RQD = Rock Quality Designation = 32

L = Total Length Drilled or Core Recovery = 11

S = RQD x L

S = 32 x 11

S = 352

Therefore, the **sum of the length of core pieces > 10cm **is **352.**

**Calculating the Total Length Drilled or Core Recovery when the Rock Quality Designation and the Sum of the Length of Core Pieces > 10cm is Given.**

L = ^{S} / _{RQD}

Where:

L = Total Length Drilled or Core Recovery

RQD = Rock Quality Designation

S = Sum of the Length of Core Pieces > 10cm

Let’s solve an example;

Calculate the total length drilled or core recovery? Given that the sum of the length of core pieces > 10cm is 26 and the rock quality designation is 42.

This implies that;

RQD = Rock Quality Designation = 42

S = Sum of the Length of Core Pieces > 10cm = 26

L = ^{S} / _{RQD}

L = ^{26} / _{42}

L = 0.619

Therefore, the **total length drilled or core recovery **is **0.619.**

Nickzom Calculator – **The Calculator Encyclopedia** is capable of calculating the rock quality designation.

To get the answer and workings of the rock quality designation using the **Nickzom Calculator – The Calculator Encyclopedia. **First, you need to obtain the app.

You can get this app via any of these means:

**Web** – https://www.nickzom.org/calculator-plus

To get access to the **professional **version via web, you need to **register** and **subscribe **for** NGN 1,500 **per** annum** to have utter access to all functionalities.

You can also try the **demo **version via https://www.nickzom.org/calculator

**Android (Paid)** – https://play.google.com/store/apps/details?id=org.nickzom.nickzomcalculator

**Android (Free)** – https://play.google.com/store/apps/details?id=com.nickzom.nickzomcalculator

**Apple (Paid)** – https://itunes.apple.com/us/app/nickzom-calculator/id1331162702?mt=8

Once, you have obtained the calculator encyclopedia app, proceed to the **Calculator Map, **then click on **Geology**** **under **Add-on.**

Now, Click on **Rock Mechanics**** **under **Geology**

Now, Click on **Rock Quality Designation** under **Rock Mechanics**

The screenshot below displays the page or activity to enter your values, to get the answer for the rock quality designation according to the respective parameters which are the **Sum of the Length of Core Pieces > 10cm (S) **and **Total Length Drilled or Core Recovery (L).**

Now, enter the values appropriately and accordingly for the parameters as required by the **Sum of the Length of Core Pieces > 10cm (S) **is **20 **and **Total Length Drille****d or Core Recovery (L)** is **14**.

Finally, Click on Calculate

As you can see from the screenshot above, **Nickzom Calculator**– The Calculator Encyclopedia solves for the rock quality designation and presents the formula, workings and steps too.