Usage Question - Quarry Explosion Monitoring

[philfry]

Hey all – New member here. I am fairly confident that I can benefit from the RS and or RS/RB to monitor and collect data on quarry blasting near a new home that I am building.

I have tried to dig into the information but wanted to reach out for some guidance.

I am considering what model of the Shake line that would be appropriate for this. I believe that the Shake would be enough to obtain intensity data on the blasts. Would the Boom provide any unique data that the Shake may not? I realize that the Boom will deliver different information, but is there recommendation from those with experience using these as to which RS/RB/RS+B would be best for this application? Thanks in advance! Really excited to explore this community and contribute once I’m up and running.

[Stormchaser]

Hello philfry, welcome to the community!

I think our @wmvanstone can be of help, since he uses our Raspberry Shakes to monitor nearby quarry blasts.

We are eager to see you active in the community!

[wmvanstone]

I personally use a RS 1D, but have access to data from other devices, including RS 4Ds and a local Geological Survey broadband seismometer with N-S, E-W and vertical geophones. The way I identify quarry blasts is by looking at the arrival times of the waves on several devices and using those to locate the source in one of several local quarries, which I can see on Google Earth, so my method is not particularly sophisticated and it relies on having several local seismometers for triangulation. In terms of choosing particular devices, I can’t comment on the RB or RS+B, not having used them. I can’t see much point in you buying a RS 4D, since the difference between that and a 1D is the strong motion detectors / accelerometers that won’t add to your knowledge of the quarry as far as I can see. I would love to have access to data from a RS 3D, with three orthogonal geophones, but it is considerably more expensive than a RS 1D. The frequency characteristics of the waves from the quarry are different to the waves from seismic events, but I have not looked into this in detail, it is on my long list of things to do. You can produce spectrograms from the single channel on a RS 1D or on multiple channels from the 3D. R614C and REE67 are a RS 4D and RS 1D next to a slate quarry in Cornwall, UK, if you are interested in looking at what they detect. That particular quarry mainly uses cutting rather than blasting for slate extraction, so it may not be representative of the data you would be collecting. I have attached the latest quarry blast detected on my personal seismometer and several other local seismometers, from a quarry near Penryn in Cornwall, UK, so you can see what I do with data that originates from a source which is less than 10km from my home.

[philfry]

This is very helpful! I appreciate the information and will be sure to post about my experience when I start collecting my data. Really appreciate the help.

[kpjamro]

If you have both RS and RB, you can determine the distance to the explosion, since the propagation times in air and ground are substantially different.

It’s actually possible to guess the range to the blast with only RS, but accuracy is much better with the RB data.

If you can get another RS unit in the same general area, then you can determine which quarry did the blast - assuming you have multiple quarries in the area.

[sheeny]

G’day Philfry, and welcome to the community.

Here is an example of a quarry blast I have detected:

I’ve been detecting and locating mine blasts for a while now - just out of interest and for the challenge, but I have been approached by some community and citizen science groups who want to check compliance of mines with their environmental vibration (from blasts) and infrasound pressure levels.

So, a couple of questions if I may…
How far away from your house is the quarry(ies)?
What is the purpose of collecting the information?

The reason I ask this is that I have been monitoring mine blasts (and quarry blasts) for some time and if you are very close to the mine or quarry, a vertical seismograph alone will not detect the P wave as it is essentially horizontal and produces no vertical movement. The S wave will show up however.

If you are only interested for interests sake, then it probably doesn’t matter, and you can get plenty of satisfaction from a RS1D or RSnB. BTW I think you’d need to be pretty close to make use of the Boom (HDF) channel - say within 10 - 20 or so kms.

However, if you want to monitor to check their environmental compliance and there is potentially some legal purpose for the data, I would recommend an RS3D as this will allow detection of both horizontal and vertical movement, so you won’t miss the P wave if you are very close to the site.

With a bit of code, the Boom channel of a RSnB can also monitor the infrasound pressure level to monitor that aspect of environmental compliance as well.

As you can see in the above section plot for Bengalla Mine, within about 40kms (no P detected up to 35kms, but P detected at 50kms) or so the P wave is not detected on a vertical geophone. Unfortunately, there are few RS3D’s around and none close to mine’s or quarries near me for me be able to produce an example of the horizontal movement from the P wave at close range from a quarry blast.

If you are interested from a hobby / curiousity point of view, just about any Raspberry Shake will give you plenty of satisfaction, but if you want to check environmental compliance I would recommend a RS3D (and and RB or RSnB for infrasound as well).

Al.

[RHP]

Hello - I am new to this and seeking a solution and to learn. I do not have this device yet, I am just at the beginning. Our small neighborhood sits on a ridge at about 2000’. Literally next to us, though not visible from our homes, is a quarry that blasts about once a month. The quarry started on one side of the mountain but has blown through the top which puts the blasting even closer to us. In my mind, these are powerful blasts. My pictures are always crooked, and I had to fix one ceiling crack that I am convinced is due to the blasting. Though we are told that they are within the law, we don’t necessarily believe this as the mining company has political connections. We are seeking a way to measure the force of the blasts and potentially share info with the appropriate state or federal authority. Is this device a good choice? Is it easy enough for an ignorant homeowner to use LOL? If so perhaps we will all get one and collectively gather data. Thanks in advance.

[Stormchaser]

Hello RHP, and welcome to our community!

Yes, there are multiple customers who use our Raspberry Shakes to monitor quarry blasts, both inside and outside the quarries themselves.

If the blasts you are experiencing are particularly intense (such as moving items inside your or your neighbours’ houses), then an RS4D is what you need.

Otherwise, depending on the data you’ll need, you can choose between our other models, with only vertical motion detection -RS1D- or vertical and horizontal directions detection -RS3D.

I’m also tagging @wmvanstone and @sheeny as they’ll surely be able to offer their insight on this matter.

[branden]

Super excited to hear that you will be joining our community @RHP , even under the circumstances. You might find that you fall in love with seismology and world-wide earthquake monitoring along the way

I just want to add that while our instruments can record seismic activity, we cannot provide guidance on making the data admissible in court proceedings, as this is outside our area of expertise.

branden

[RHP]

Thanks so much - I will take a look at the products, and also share this information with my neighbors. It’s a frustrating and concerning situation. We are trying to gather data so we understand the magnitude of the blasts and whether they are, in fact, under whatever is the legal limit…

[sheeny]

Hello @RHP.

Sorry for the late reply, I am just back from 3 months traveling around Australia.

I regularly monitor mine blasts within 200-300 kms of my station using multiple Raspberry Shakes on the network to try to identify where and when the blast was, etc simply as a hobby and a challenge. Occasionally I get to find an earthquake instead which has been dismissed by the authorities as a mine blast, but of course if the location doesn’t coincide with a mine site then its not likely a blast. ;o)

To check whether the blasts are compliant, you first need to get a copy of the the mine/quarry’s environment consent conditions. The consent conditions will determine how easily (or not) you can check for compliance.

For example, I consulted with some people doing exactly this, and the compliance conditions they were dealing with was a maximum ground movement at any neighbouring residence of less than x m/s, and a maximum blast pressure at any neighbouring residence of less than y Pa.

This is the simplest scenario for citizen checking. If you are very close to the site, you would probably need an RS3D or an RS4D to measure the ground movement as sometimes the horizontal ground movement will be larger than the vertical. It is unlikely that you can get away with an RS1D if you are close enough to be concerned about the blast, as it will miss all the horizontal ground movement.

If you need to monitor the air blast as well, then an RS&B is required to measure the atmospheric blast in Pa.

If the consent conditions are different, or in different units, then it is not so straight forward, but there are examples of python code that can be used to calculate the ground motion in either displacement (m), velocity (m/s) or acceleration (m/s/s) regardless of what units the Shake measures it in. Likewise python code can be used to convert the infrasound signal from an RS&B to decibels if required.

If the consent conditions don’t specify a limit at a residence, then things can be more difficult again to be able to capture meaningful data.

As Brandon said, if you want to present this data in a legal situation, that’s a whole other ball game, but if you want to satisfy yourself of compliance and when its appropriate to complain, then a Raspberry Shake is the way to go.

Just as an aside, non-compliant blasts are rarely deliberate IMO. From talking to a local quarry owner, he said his biggest fear is a void in the rock. When they set a blast, they drill to a depth and fill the hole to a level with explosive. If they drill through a void in the rock, the explosive fills the void as well the hole, and this creates a much bigger explosion. It’s both non desirable and non-compliant, but they have their own monitoring to check for compliance and have to report the results to EPA (at least in Australia).

Al.