Plesae give your ngineering opinion 2

[geotechniqa]

Hello guys
A head person in my company has asked me to go and inspect a big tailings dam in remote site (interim preliminary inspection to ensure safety for a short run). "Direction by telephone could have been provided to me" the person said

I have never inspected such kind of huge structures before and they need only one person to go. Although I have the theoretical background about tailings dams ,but I believe that these kind of tasks require judgment and experience more than science. I think that for couple of times I should by doing that under a supervision of experts. What do you think..?
Appreciated

Therefore, I said this work is beyond my capacity. That man accepted nicely. However, when I requested to be involved partially so that I can learning the process. The person again said that only one person only should be involved.
Plesae give me your opinion on the matter.

 

[cvg]

last major dam inspection I was involved with lasted nearly a week and involved a team of engineers, including 3 civil, 2 structural, 2 geotechnical and also included non destructive testing, soil borings and concrete coring. the dam was partially dewatered to allow better inspection. Granted, this was more than just preliminary, but I'm not sure what you will learn with just person for limited time. Sounds like cost is the primary factor, not obtaining useful information. Absolutely, you should either be an expert or accompanied by one. And, as with most dams, no one expert can understand everything. Usually requires hydrologist, geotechnical and structural at the very least. If this is truly in a remote site, I usually avoid going into these places by myself for safety reasons. We always send a team of two minimum for all remote field trips.

 

[Unotec]

What are you inspecting it for? What are the concerns? It can be integrity, pollution, corpses.... it all depends on what the investigation is for what the requirements are

<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying ” Damn that was fun!” - Unknown>>

 

[dgillette]

Definitely not a solo project. It requires, at minimum, unotec and his true friend. Depending upon what you are looking for, you may need a mining engineer, a geotech, a geologist, a structural engineer, a mechanical, and/or a biologist. Besides, the more eyes there are, the less likely it is that something gets missed. Add another vote with cvg (from Cincinnati?) and unotec.

The inspection part definitely requires a detailed knowledge/experience base on how they are constructed, evidence of problems, vs relatively benign seepage and erosion or sloughing, etc. Twenty years ago, I was tangentially involved with investigating one that failed, possibly due to bad location of the cyclone discharge. Had I gone out there the day before, would I have noticed that? Probably not, regardless of how well I knew undrained shear strength, large-strain consolidation, and slope stability, but an experienced tailings-dam guy would have seen it and raised the alarm.

 

[msquared48]

This is a CYA situation. Without the experience personally, and the willingness of an expert in the situation to help you out, bail out.

Mike McCann
MMC Engineering

 

[cvg]

star for Dave and no, I'm not from Cincinnati

add surveyor to the inspection team to verify the dam slopes, freeboard etc...

 

[civilperson]

Take a digital camera and a 25 foot rod for scale and shoot the site with 50% overlaps everywhere. Get the local topographical map for all flows and upstream contributing areas. Use the boundary survey and plat as key to identify all your pictures and observations of ground cover and soil types. Write a short narrative and bring it all back to the office titled "Preliminary Survey". Receive all criticisms gladly and then go and do it better the second time! When the technical experts are brought on the team, you will be the local source expert in hotels, restaurants, parking, etc.

 

[Unotec]

And watering holes!!!!

<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying ” Damn that was fun!” - Unknown>>

 

[geotechniqa]

msquared48 sorry what is CYA.?
Guys... do not forget that I was requested to go alone alone without even a technician. Do not forget that although it is preliminary but my stamp is required to be affixed on it.
I saw a tailings dam once in my life time. In general Inspections tasks require experienece more than degrees which are neccessary but not sufficient.
Correct me If I am wrong. Was I fair with the company when I said no in this state

 

[Unotec]

I would have refused to stamp any investigation I'm not comfortable with the results I am going to generate. But the refusal would have been polite.
Now, how remote is 'remote'? And what are you looking for?
I did a few dam evaluations that I did not had to stamp but common sense made me identify what i thought were flagrant flaws. However, I did warn that someone with more knowledge should take a look too. When the experienced foreman showed up, he did find a few things that were not obvious to me.

<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying ” Damn that was fun!” - Unknown>>

 

[civilperson]

Stamp your report with impunity, you can write weasel paragraphs excluding below grade conditions of water and soil, slope stability and any other thing you do not know for SURE! If what you write is factual, where is the problem? You are not doing an in depth analysis but giving hints for further investigation. Your conclusion can say hydro-geologists review, chemical analysis and biological studies need to be done for a complete assessment as well as borings/sampling/testing for a soil profile.

 

[cvg]

given that a) you are not an expert and b) you do not have time or resources to conduct a thorough inspection, you cannot, as you are being requested - "ensure safety" at this dam by doing your inspection. You may be able to make very few conclusions at all. All you can do is document what you see with photos, measurements and perhaps gather some samples and leave the conclusions to others who may review your work or examine the samples later. If your inspection report does not present any results (requiring engineering judgement), than no problem stamping it.

suggest you increase your knowledge by looking at some of the following resources regarding dam safety, O&M and emergency actions

http://www.fema.gov/plan/prevent/damfailure/publications.shtm

 

[fattdad]

While multiple diciplines may be ultimatly needed to evaluate much of what's already been stated (i.e., soil strength, habitat encroachment, slope stability, hydrology, hydraulics and the like), you can certainly go it alone. Bring your clinometer and measure your own slopes. Bring a sheet of graph paper and a tape and measure your own slope angles. Maybe a "pop level" to get some basic elevation control. Do a field reconnaissence for gopher holes and the like (or trees growing on the slope). For this approach, you would ultimatly go with the intention of designing a suitable followup program, likely to include much of what has already been mentioned.

It's often prudent engineering to have an initial field assult prior to getting the real work done. Whether you are the correct person for this task is a separate topic. I guess your boss thinks so and you do not.

Then again, I may be missing something.

f-d

¡papá gordo ain’t no madre flaca!

 

[geotechniqa]

Wether you do things right or not do it. You should know that this is not a house foundation or a slope in a backyard. It is a gaint structure that requires a lot of overviews. I have learnt in my life to do things in an ideal manner or stay far from them.

 

[dgillette]

cvg - I just asked that because years ago, I knew a civil eng whose initials were CVG, which I thought was amusing because the Cinci airport's code is CVG. (I'm easily entertained.)

Evidentally, you are not that particular Chuck V.G.

DRG

 

[civilperson]

Cinci's airport is in Kentucky. (confused the heck out of me while doing the UPS extention!)

 

[DRC1]

If you are not comfortable doing the review, you should not do it. You have not only done yourself a favor, but the client also. He does not need to hire you to go out there to get a report that doesn't give him relevent information. If you haven't worked with dams, you probably won't see what is important. For example, tailing dams are often prone to piping failures. Evidence of early piping may go unnoticed if you don't know where to look.
Also these guys do not seem interested in an indepth review. They may only want a CYA (cover your backside)report should there be a problem.
I think you made the right choice.

 

[geotechniqa]

Thanks alot DRC1 for this loyal advice.

 

[dirtguy4]

geotechniqa,

I can appreciate your situation. As I was a young engineer once, I understand, as an employer, I want to see what you got to offer. Why are you getting that salary and bonuses and how can you contribute to the firm?

You may want to really think about turning tail on this one and look at it as a challenge. Maybe this is your Everest, you over come this and you can basically write your own pay cheques. Keep in mind, you have senior staff to go to, if not go to the owner/president of your firm (he's the man ending up in court), if not them then find another engineer......heck all of us on this site will help as much as possible and if no one else will step up....I will.

I understand your apprehension, but sometimes you have to get out of your comfort zone a little and learn that the process of site investigation and observations and documenting and attention to detail and the scientific process of analyses works. And will always back you up in court. I went here....on this day.....I observed this....deficiencies noticed are as follows.....The issues are this.....I recommend a more complete investigation with a combination of other professionals....etc.

Of course I am over simplifying the situation, but ultimately geotechniqa, the person who pays your liability insurance is the one who ends up in court. So they are the ones who need to evaluate whether you are qualified for the job and unless you lied on a resume, they must feel that you have the qualifications.

You have all the tools in your tool box......just have the confidence in using them. This is what your boss is looking for. So I challenge you, roll up your sleeves and engulf yourself in the world of engineering, grab the wheel with both hands and tell yourself what would Karl Terzaghi or Ralph Peck do in this situation.

I guarantee, this is the spirit that your boss is looking for. Show this style and attitude and you will get all kinds of help and direction from senior staff.

 

[dgillette]

"So I challenge you, roll up your sleeves and engulf yourself in the world of engineering, grab the wheel with both hands and tell yourself what would Karl Terzaghi or Ralph Peck do in this situation."

It would be instructive to read some of Peck's writings on his earlier years in practice, and the times that Terzaghi caught something in the field or in the analysis that Peck had missed due to his relative inexperience. I knew him fairly well in his later years from the times we hired him as a reviewer on our projects, and he (like Terzaghi) was always a strong advocate for heavy involvement of geologists on dam projects. I don't believe I would cite him in arguing for boldly charging into an area where you uncomfortable with your own qualifications.

We're not talking about a house foundation here; it's a big tailings dam, with complex technical issues and potentially huge consequences from errors (environmental, fatalities, economic damages both off property and from loss of use). I stand by my earlier conclusion - unless you are Reinhold Messner, don't solo Everest.

At minimum, read S.G. Vick's book on tailings dams.