The Canadian junior rare earths explorer said that Holmström will represent the company locally, as well as implement management's vision for the development of its flagship Norra Karr heavy rare earth element project, located in Sweden.
Holmström previously was project development manager for Norra Karr, and was key in the submission of the mining lease application for the project announced earlier this month.
"Henning has provided great leadership for the Swedish team as we collected the environmental data, undertook community meetings and prepared the necessary documentation for the Mining Lease application," said Tasman's president and CEO, Mark Saxon.
"As Managing Director of Tasmet AB, Henning will have a strong voice to with which to represent Tasman Metals in Swedish and European forums, as Norra Karr progresses towards development."
Holmström holds over 17 years of experience, having filled consulting, corporate and government roles prior to joining Tasman in September 2011.
Prior to Tasman, Holmström held a senior management position with international consulting group, Golder Associates AB, as the client sector leader of mining in Scandinavia.
Tasman Metals also announced Wednesday the expansion of its advisory board with the appointment of Heather White and Dr. Dag Øistein Eriksen, in response to the rapid development of the Norra Karr project.
White is a mining engineer, with 16 years experience in Canadian and international roles, and was mine manager for the Voisey's Bay mine in Labrador for a two year period.
Eriksen is based in Oslo, Norway, and was previously a senior scientist at Megon AS, renamed Extratec AS, which researched leaching of various REE ores and developed the well known "Megon process" for the extraction and purification of yttrium by solvent extraction.
Eriksen is expected to help Tasman in assessing various processing and separation opportunities.
The company earlier this month reported that it submitted its application for a mining lease for its heavy rare earth and zirconium Norra Karr project in Sweden.
Norra Karr is one of the largest and most economical projects among its peers, due to the high contribution of the high value rare earth elements like dysprosium (Dy), yttrium (y), neodymium (Nd), and terbium (Tb).
The mining lease, under the Swedish Mining Act, will be valid for 25 years, at which point it can be renewed.
Tasman said the mining lease application will take about six months to process to completion, and is a major step prior to attaining the actual extraction permit, which is expected in late 2014.
The company released in March a positive preliminary economic assessment for Norra Karr, detailing a project that boasts a pre-tax net present value in excess of $1.46 billion at a 10 per cent discount rate, and an almost 50 per cent internal rate of return, with a payback period of 3 years from the start of construction.
The total capital cost estimate for the project is a relatively low $290 million over a one and a half year construction period, with the property also boasting simple mineralogy that "allows for ambient temperature and pressure processing", the company noted in a statement.
Norra Karr is the only NI 43-101 compliant rare earth element resource in mainland Europe.
The PEA was based on an open pittable recoverable resource of 58.1 million tonnes grading 0.59% TREO (total rare earth oxide) where 50.0 per cent of the TREO is the high value heavy rare earth oxide (HREO) and 1.70% ZrO2 (zirconium oxide) in the inferred and indicated categories.
The Scandinavian-focused miner also has the Olserum project, which it acquired last October and is located 100 kilometres east of Norra Karr.
Last month, the rare earth explorer also acquired three new rare earth element exploration properties in central Finland. The Korsnas South, Siilinjarvi and Laivajoki projects are being acquired from private Finnish company Magnus Minerals Oy.
Shares of Tasman Metals traded at $1.40 Wednesday.