THE electrical and securities equipment company, Silvermines, has sold the Marine House office block in Dublin for Pounds 4.4 million and made two small bolt on acquisitions, in Britain and the US, for Pounds 1.75 million. Silvermines has also placed 3.2 million new shares at 61 1/2p per share to raise Pounds 1.9 million.

Silvermines has been trying to sell Marine House and the Shannon Business Park project for some time. The Shannon property is still for sale and the group is looking for between Pounds 2.5 million and Pounds 3 million, said its finance director, Mr Lloyd Trinkoff. Property does not form part of the group's, core businesses, he added.

Marine House was sold to an undisclosed Irish property investor for Pounds 4.4 million cash. The book value was Pounds 4.25 million so there is a small gain. The property has a rental income of Pounds 445,000, which puts the consideration on a gross yield of 10.2 per cent.

When the Shannon Business Park is sold, Silvermines will have no property interests. It will then focus its activities on electrical and security businesses.

The new shares were place with British and Irish investors. The price was at a discount of 2 1/2p, or 4 per cent of the previous listed price.

The gearing after all the transactions will be around 20 per cent, according to Mr Trinkoff. The proceeds will be used to fund the acquisition of Falcon Equipment and Systems for Pounds 300,000 sterling cash, representing the net asset value off the business, and

Silvermines is to contribute an additional Pounds 100,000 to the working, capital of Falcon this year.

Falcon had a turnover of Pounds 1.3 million sterling in the year to April 30th, 1995, and broke even. It specialises in the design and development of electronic system will be integrated with Silvermines CCTV manufacturing, subsidiary Molynx, in Newport, Gwen Pickering, based in Plainview, New York, designs and manufactures linear transducers which are complementary to those manufactured by Silvermines' subsidiary, Muirhead Vactric Components.

Pickering recorded sales of over a three year period.

Silvermines Auto Products (SAPL) has been formed to exploit new opportunities in the automotive, sector, Silvermines said. One project is, expected to generate, sales of Pounds 11 million sterling beginning in 1997. This is expected to rise to some Pounds 30 million by 2001.

Silvermines, joint developments agreement with Mitsui, for expansion in southeast Asia, China and Japan, is going according to plan. As part of the arrangement, Mitsui took a 2.5 per cent shareholding in Silvermines last year.