Although I had not been in contact with John since college,  I reminisce about how he taught me how to make a gin & tonic along with singing Tom Lehrer songs together on road trips. 

J'ai appris avec beaucoup de tristesse, le décès de Dr. John Mahoney, géochimiste confirmé. J'avais l'occasion de le connaitre via internet, je me suis inscris dans une de ses classes sur Phreeqc, mais j'avais pas eu l'occasion de le côtoyer. Très sympathique, adore aider les gens en difficultés, on a beaucoup appris avec lui sur l'application de Phreeqc à la modélisation des processus géologiques. C'est une vrai perte pour la communauté scientifique. Que son âme repose en paix !!

I was shocked and saddened to learn about the death of John Mahoney  I imagine your grief must be overwhelming, I will cherish the memories I have of John. I remember meeting John for the first time in Calgary 2014 over a Geochemistry/Geochemical modeling course...His jokes and sense of humor made everyone laugh, and his smile lit up the room. I learned a lot from John in geochemistry. I wish you peace.

I knew of John as a scientist and a major contributor to geochemical modelling before we formally met.

John contacted me earlier this year, requesting assistance with his online geochemistry course which he was designing. I was very grateful to have John's confidence and respect as a geochemist, but quickly became aware of John as a deeply kind, humorous and intelligent man of the world.

We developed an email friendship, and I came to greatly enjoy his extensive vocabulary and wit.

I was further humbled by John's subsequent request to frankly assess his most recent publication in preparation. It meant a great deal to me at a difficult time of my life to have the confidence and faith of a big man such as John.

I remember John very fondly and rue the disappearance of such a leading light in geochemistry. My heart goes out to those who knew him better than I did. This must be an invidious time to be living through.

I’m grateful to John for giving me my start in the world of consulting at HCI 27 years ago after I had finished my masters degree. I remember many discussions and brainstorming sessions about geochemistry and of course Phreeqc.
He was certainly a rare breed.  He once described himself to me as a “mental packrat”, a somewhat self-deprecating term that meant he had a mind like a steel trap. I was always amazed at his ability to remember details that I had long forgotten. He was a mentor and a friend, and I learned much from him.

John was a friend, a colleague and mentor for Wanda and I and we will miss him. He was a kind and sharing man, and was of immense help during my years of marginal employment. John gave me problems to solve and chatted with me and helped me stay technically engaged. My time with John last May in Colorado at his short course was so much fun and fulfilling. It lifted my spirits and helped me keep a positive attitude while I looked for work.

We have know John since his work on the Saskatchewan Uranium mine in the late 90s when Wanda and I were in grad school in Saskatoon. 

For Wanda and I meeting Dr. Langmuir and Dr. Mahoney was life changing. We have fond memories of our trips to Colorado to study geochemistry and visit with John and Don. Years later his visits to Edmonton to teach the geochemistry short course with me while I was a professor were the highlight of the year.

Wanda and I will miss John as a friend and I will miss him as a colleague and mentor. John made me a better geochemist.

I am so sorry to hear of John's passing. I will never forget how John helped me out on a project when I was in over my head. A very kind and intelligent man who was just fun to be around. He will be missed.

John has gifted us for many years with his geochemical genius and wonderful wit. His intelligence, insight and generosity of spirit has made the world demonstrably safer and better understood while enabling many of us to learn and grow as professionals. We can't imagine doing this work without him, his fantastic stories, and many Marc Twain quotes. He will be greatly missed. Our sincere condolences, from all his friends and students at Orano (Areva) past and present.


To know John and your family has been a wonderful time in my life I enjoyed hearing stories of far away places that John traveled to for his work. I will miss him and the stories but have the memories. My condolences Mary Ann

Hello Susan:

Thank you for taking my call today. I am deeply saddened by the news of John's passing and offer my sincere condolences to you and all family. I knew John professionally through a number of projects that we completed jointly in Canada, but through all of those professional dealings we had many sidebar conversations about life in general. He was a kind and very funny man, and the stories he could tell were seemingly endless. We were gearing up to work on another project and I can only say that I am thankful to have had several conversations with him over the past few months. He will be missed, but not forgotten. I am truly sorry for your loss.

John's willingness to share his knowledge and his time made him a generous friend. John's willingness to share his family brought a brightness to my life. I am grateful I had the chance to know him. He will be missed by all.

Our deepest sympathy to Susan and James and Katie,
Cary and Carol

Oh my, John we will miss you so.  I have known you for so long.

You were always there to cheerfully help me with any technical problem. You often had a solution, but at least, always, a suggestion on something to try.

Many of our talks were at dinner or over a drink. Often the solution to my problem was explained on a napkin. I have kept several of the napkins. They were always special and now they are a treasure. They often had a series of chemical equations, but one in particular had diagrams groundwater movement below the permafrost in the tundra. 

Our trips to Brazil with the great GAK were always eventful and your ever cheerful and often witty comments about events were effective when the tensions rose at differing opinions. 
We enjoyed his calls for “Mas cerveza….muy rapido!!”  You could imitate him so well. 

John you are such a cheerful person, that I am sure the angels will be happy to have you aboard. You are probably teaching class right now and discussing the attributes of the works of Mahler. You were so helpful to those less capable than you and you could teach the very difficult without making the student feel ignorant. Your presentations were always fun and you observed so many things in life that others might likely miss.

We had some fun at the Black Woods campground in Acadia on a spring BU field trip. It’s wonderous that we didn’t fall into the campfire from too many spirits. Or, maybe we almost did??

I am forever amazed at all you could carry in your mind. The people the places and the technical information, oh my goodness! You were skilled at explaining deep technical processes in terms of everyday events that we all understood. 

John, in the words of Vera Lynn “We’ll meet again, don’t know where, don’t know when…”
May God keep you safe until then and always.

Your admiring and caring friend forever, 

Cary Parsons. 


John was a colleague who was passionate about geochemistry and the understanding of geochemical processes.  I learned much from him and I have the highest respect for his intellect.  He was a joy to travel with on business trips as he had a keen wit and a sense of adventure.  He will be missed!

I treasure the time spent working with John. He taught me and others so much and helped us to grow in our lives and careers.  Some of John will continue to be in all of us and we should take comfort in that.  My thoughts and prayers go out to John’s family. 

I am very  sad to hear the sad news on John. John was my direct supervisor when I joined HCI. I learned a lot from him and developed a good friendship with him.  I respect John very much both professionally and personally. Up until the past two to three years, John and I always had at least one annual lunch together. His favorite Chinese restaurant is Imperial Chinese and favorite dish is sesame chicken. It was very consistent over years! 


John and I exchanged tales (mostly his) and discussed geochemistry over many lunches here in Denver. To be honest, I could not keep up with his current and potential consulting jobs that ranged from Canada to central Africa, to Brazil, back to Indonesia, Chile, Australia, and "Joberg".  But he had the courage to work as an independent consultant, with some years hectic, and some too slow.

He still had a bit of that Boston accent and preferred the Patriots and Red Sox to the Broncos and Rockies.  He liked musicals and we once attended the opera together.  He also had a penchant for obscure European murder/mystery TV series. 

John truly enjoyed geochemistry and geochemical modeling. He got pretty excited discussing the thermodynamics of minerals I had never heard of, but he did some of the hard, real-world work  on mine-water contamination and amelioration. He taught many classes and was always generous with his time for graduate students.   I think there are few other geochemists to fill the hole that he leaves. 

I'll miss our time together, his humor, and his expertise. 

Our condolences to the Mahoney family.  Let your memories of John bring you peace and comfort.   Scott and Lorna


John was a mentor to me in geochemistry.  He always took the time to make sure that I truly understood what I was doing.  

Every time that I would call him he always updated me on the status of his family.  He loved & cared for them deeply.

I always remember John when I am just about to run out of gas in the middle of nowhere.  Coming back from a job in Wyoming, I told him we can probably make it to the next gas station.  John said “What if we don’t”.  We then got gas and a delicious coconut snow ball.  I always followed his advice!

I am sad to hear of the passing of John.  I enjoyed working with John , he was a very smart guy, but what I remember the most was his jovial nature and  his sense of humor was great.  I can still hear him chuckle.

Susan and Family,

Just wanted to express my condolences about John's passing.  I knew John for almost 20-years, he had worked with me on a numerous projects over the years and we were working together on two more when he passed.  He was a wonderful man from the perspective of being so sharing with his amazing technical knowledge (and patient explanations), but even more so he was a just a kind and generous guy.  Know that he will be missed by many people around the world.  Warmest Regards, Ken  

Very sad news. John was my student at Mines, and thereafter a friend and colleague in many publishing and consulting endeavors.  In these efforts he was clever, imaginative and enthusiastic.  Our conversations ranged from the geochemistry of arsenic and uranium to our favorite symphonies and operas.  John will be sorely missed.


I met John on a cold winter day in Montreal, where we spoke about arsenic for hours.  The undesirable elements brought us together, and continued to bring us together over the years.  I consider myself fortunate to count John as a mentor.

I met John in the summer of 1959 when Mrs. Mahoney drove several kids from the neighborhood to the movies. His sister Mary and I became lifelong friends, and so I knew John growing up, and into our 20s. Though I haven't seen him for many years, I remember him well -- his sharpness, his love of the mountains, and especially his sense of humor. He was a good guy, and I'm very sorry to learn of his passing so young. My heartfelt condolences to Mary, Susan, Katy, and James, and all those who loved him.

Our deepest condolences to Susan, James, Katie, and John’s family and friends.  We met John in graduate school at the Colorado School of Mines too many years ago.  John was a gifted geochemist and I’ve always admired his exceptional computational abilities and extensive, encyclopedic knowledge base.  I remember fondly that John was always able to come up with a story or limerick for every occasion.  John was a special person, and he will be greatly missed. We hope that you can hold close your memories of John and that they will provide you with some comfort for your loss.
Kathy Smith and Steve Gebhard 

John was one of the first people that I worked with straight out of school when I started at MWH over 13 years ago. He was happy to help explain geochemistry to me whenever I had questions, often multiple times, and never was irritated or make me feel that I couldn't ask a question. That was very helpful at the beginning of my career. After he started his own company, we would still keep in touch and John was always an advocate even if we didn't talk for years. 
John truly cared about the people in his life and the work that he did. He had an impact on my life and will not be forgotten. I send my condolences to his family and friends.

I knew John as a kind and positive person, and also as a very gifted geochemist.  We met in the 1980s when working together at Battelle Pacific Northwest Laboratories in Richland, WA.  I remember skiing with him on Super Bowl Sunday 1988.  This sticks in my mind because I recall he hurt his knee, and we got home in time to see most of the game, a Washington blowout of our Denver Broncos.  John's son James and my son Nathan, our eldest children, were born within about a week of each other in Richland in 1987.  I stayed in occasional contact with John over the years, and I took his PHREEQC class in the Denver area in 2015.  It was a very thorough, and well-executed class, sprinkled with references to Pangloss.  My deepest condolences and many prayers go out to Susan and her family.  Having lost a spouse very suddenly almost 6 years ago, I can offer that the pain and mourning will subside over time, and all the good memories will remain as treasures.

I was fortunate enough to get to know John as a student in a few of his professional training courses. When I first met him, I remember being immediately struck by what an all-around nice guy John was, with a great sense of humor and a contagious laugh. Professionally, he had an amazing and deep technical knowledge in geochemistry, and he was always so generous with his time and mentorship.  John will be truly missed.  My deepest condolences to the family.

I met John about 15 years ago.  We worked together on a project, and continued to stay in touch over the years.  John was exceptionally talented and a pleasure to work with.  I have very fond of a 20-hour work road trip from Walnut Creek California to Denver, where John entertained us with wonderful stories, poems, songs, and limericks.  John was special and will be dearly missed.  My sincere condolences to the family.  

I first met John in the early 1970s. We frequently climbed togather, winter and summer, in the White Mountains of NH and discoverd we also loved fly fishing . John and Susan subsequently introduced me to my now wife of 40 years. 
John, we will sorely miss you. Our sincere condolences to Susan and the family. 

Bob & Linda Bicknell

John was one of the first people I met when I moved to Colorado we climbed together first at the link and then outdoors he was an incredible man andl I will miss him immensely. I was a part of his family and we spent many thanksgivings and Christmases together I will miss him forever.  Susan  Cathy  James my depessit condelences

John and I were graduate students at the Colorado School of Mines thirty-five years ago and later became independent consulting colleagues, sometimes sharing projects and clients.  John was the technical geochemist I only aspired to be, and I admired his knowledge and his pursuit of computational excellence.  Some time ago he asked me when he should consider retirement.  I told him ‘when it’s not fun anymore’.  Obviously, he was still having fun – and that is a good thing!  He will be missed.

John got me started in rock climbing many moons ago.  It was a great escape from graduate shool to sneak out to Clear Creek with him.  He even gave me one of his climbing harnesses to start my gear collection.  A long while later, when I bought my own harness, I confirmed what was apparently well known in the climbing community. That harness was one of the most uncomfortable designs ever!  Thanks John.
I send my deepest condolences to all of Johns' family and hope that your memories of him bring some measure of joy to ease the sadness.

My condolence go out to John's family and friends. He was instrumental in my ongoing education and was always willing to help. I will miss him. 

OBITUARY

John Joseph Mahoney

July 1, 1953 – October 27, 2020

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