Jim Koerselman

Chairman of the Board

Joined Demco in 1964.
I am the second generation in our family owned business. In the course of 50 years, it's been exciting to see Demco grow from just 10 employees to over 300 employees. I'm enjoying my current role of consulting the 3rd generation.

Robert Koerselman


Joined Demco in 1988.
I started working at Demco in 1988. However, being 3rd generation, Demco has always been a part of my life. I feel very blessed to have worked side by side with my father in our family business. I'm very passionate about innovation in all the industries we serve. By surrounding myself with great people I will continue the strong tradition set before me.

Kevin Ten Haken

Executive Vice President & Cost Accounting / Purchasing

Joined Demco in 1986.
I graduated from Minnesota State University (formerly Mankato State University), BS in Finance/Mgmt. I initially worked at Citibank NA in Sioux Falls prior to coming to Demco. I have been at Demco since 1986 and have been involved in a number of roles prior to being in my current position of Executive VP. My wife Kim and I have four wonderful children. I am actively involved in a number of non-profit organizations in addition to my church. I enjoy time spent with family, being a grandparent, and when time permits, golf, motorcycling, beekeeping and gardening, etc.

John Tatman

Spencer Plant Manager

John was born and raised on a farm in Sioux Rapids, Iowa. He started his career working on a farm for 12-years as general laborer. Many skills were gained through the farm upbringing and the farm-labor experience. This experience has given John a strong background for working at Demco. He began on the welding floor, then moved to other departments, such as working in the warehouse, fabrication and painting. Now John is the plant manager for the Spencer facility and holds a seat on the Demco management team. The broad base of experience he brings to the team is very insightful and hands on. He has the ability to see things from a very objective point of view which is very good in leading Demco forward.

Benji Vande Griend

Director of Sales

Joined Demco in 2010
Benji was born and raised in Northwest Iowa on a farm. In his early career he held various professional positions which prepared him as the perfect fit for our Agricultural products sales manager. From the very first day, Benji fit into the Demco team striving to work with each team member for the greater good of all. He can be found at many industry events across North America working with our dealers, distributors, sales representatives, and co-workers.

Mark Nilles

Vice President of Operations

Joined Demco in 1989
Born and raised in northwest Iowa has allowed me the opportunity to become familiar with the community, the people and Demco as a company. Having worked at Demco for several years I appreciate the integrity and values that represent this company. Working in various roles at Demco from production, sales, managing the printing department, Director of Engineering and now Vice President of Operations developed my skills in process improvement and managing people. I really enjoy helping team members through challenging situations and watching them grow as a result of those challenges. It is very satisfying to help our team find solutions to situations and help improve our processes as a result of team members working together to improve products and develop new products. The results are a strong team with the vision of moving Demco forward into the future for our customers, our team members, and our community.