u/Zoranis1

Hi all,

I work as a casual employee (once a week, 9 am to 5 pm) measuring rock properties. We recently received radioactive core samples from Olympic Dam, BHP, Australia. The samples are approximately 20–30 cm long and 5 cm in diameter.

I am not sure what minerals are present, and I have not been able to identify them. I know that there are some uranium-bearing minerals (probably uraninite). My boss has not disclosed the lithology, or perhaps BHP did not provide this information.

My boss gave me a fairly poor induction on how to handle the samples, and I am concerned about long-term exposure. He said that the samples have very low levels of radioactivity. I asked whether we could buy a Geiger counter. We have a portable X-ray machine, which I asked about during a different event, but he was dismissive and said that it was not necessarily needed, etc. You know the type of boss who does not seem to care much about employee safety.

Anyway, he showed me a gamma-ray spectrometer. It is quite old, and based on the manual, I do not think it is calibrated or properly stabilised. It is an RS-125:
https://www.aseg.org.au/resources/equipment-manuals-brochures/radiometrics/

The CPS reading in the lab is around 200. The samples are around 400 CPS, with some reaching up to 600 CPS. If I understand correctly, CPS itself does not tell you much, as the device needs to be properly calibrated and other information is required to assess the actual radiation exposure.

The RS-125 gave a very low dose-rate reading: around 4.2 nSv/h for the background and about 5 nSv/h when measuring a sample. However, given that the device may not be calibrated, I am not sure how reliable these readings are.

We currently have around 100 samples that have simply been left on a table, and we expect more batches from the company (possibly another 500 samples). That is why I am concerned about whether handling these samples even one day per week could potentially cause health or safety issues. It will be a 2-month job.

I am currently using a waterproof apron (my boss said he is going to provide lab coats), disposable vinyl gloves, and face shield. We are not cutting the samples, but there is a measurement that will submerge the samples in water for at least one day.

It is not as though I have felt my hands burning or experienced anything unusual, but I am concerned about long-term exposure. Am I overreacting, or is there something I should be doing to mitigate risks?

Let me know if you any advice or material on what would be considered appropriate safety procedures in this situation, particularly regarding radiation monitoring and long-term exposure. A Geiger counter would suffice or I should look for other type of monitors? I am thinking in contact also ARPANSA (Australian Nuclear Agency) for help on this.

Hi all,

I work as a casual employee (once a week, 9 am to 5 pm) measuring rock properties. We recently received radioactive core samples from Olympic Dam, BHP, Australia. The samples are approximately 20–30 cm long and 5 cm in diameter.

I am not sure what minerals are present, and I have not been able to identify them. I know that there are some uranium-bearing minerals (probably uraninite). My boss has not disclosed the lithology, or perhaps BHP did not provide this information.

My boss gave me a fairly poor induction on how to handle the samples, and I am concerned about long-term exposure. He said that the samples have very low levels of radioactivity. I asked whether we could buy a Geiger counter. We have a portable X-ray machine, which I asked about during a different event, but he was dismissive and said that it was not necessarily needed, etc. You know the type of boss who does not seem to care much about employee safety.

Anyway, he showed me a gamma-ray spectrometer. It is quite old, and based on the manual, I do not think it is calibrated or properly stabilised. It is an RS-125:
https://www.aseg.org.au/resources/equipment-manuals-brochures/radiometrics/

The CPS reading in the lab is around 200. The samples are around 400 CPS, with some reaching up to 600 CPS. If I understand correctly, CPS itself does not tell you much, as the device needs to be properly calibrated and other information is required to assess the actual radiation exposure.

The RS-125 gave a very low dose-rate reading: around 4.2 nSv/h for the background and about 5 nSv/h when measuring a sample. However, given that the device may not be calibrated, I am not sure how reliable these readings are.

We currently have around 100 samples that have simply been left on a table, and we expect more batches from the company (possibly another 500 samples). That is why I am concerned about whether handling these samples even one day per week could potentially cause health or safety issues. It will be a 2-month job.

I am currently using a waterproof apron (my boss said he is going to provide lab coats), disposable vinyl gloves, and face shield. We are not cutting the samples, but there is a measurement that will submerge the samples in water for at least one day.

It is not as though I have felt my hands burning or experienced anything unusual, but I am concerned about long-term exposure. Am I overreacting, or is there something I should be doing to mitigate risks?

Let me know if you any advice or material on what would be considered appropriate safety procedures in this situation, particularly regarding radiation monitoring and long-term exposure. A Geiger counter would suffice or I should look for other type of monitors? I am thinking in contact also ARPANSA (Australian Nuclear Agency) for help on this.

Hi all,

I am analysing histograms of rock physical properties (geologist here) plotted with a logarithmic x-axis, and I was discussing the results with my supervisor. One of the distributions is clearly multimodal, with three distinct peaks, and I argued that it differs from the log-normal distribution that appears to be more characteristic of Rock X.

My supervisor then asked whether a distribution can be both multimodal and log-normal (for example, as a mixture of two or more log-normal distributions), or whether a log-normal distribution is, by definition, always unimodal.

Hi everyone,

I am working with a draped airborne survey (magnetic TMA and gravity Tz) acquired near the magnetic equator (I = −4°) over a geologically complex area. The data are already terrain-corrected (it used a density of 2.2 g/cc by acquisition company). Since this is real data over a complex area, I cannot build a synthetic geological model to compare, so I am looking for a way to assess whether residual topographic effects are present in my data and 3D inversion results.

My idea is to:

1.    I have my mesh with topography added. My idea is to compute a forward model of this mesh where I will just use cells between the surface and a flat datum (i.e., elevation equal to 0 m in my mesh). My 3D mesh has no air cells.

2.    Assign a constant magnetic susceptibility for these cells in the forward model, I was thinking using 0.01 SI. For density contrast model I am less sure which value to use, maybe 0.1 g/cc.

3.    Do data_residual = data_observed − data_from_topographic_mesh

and see if residuals contain any topographic signature.

Do you think this idea can work? Let me know if you have other approaches.