Finally found the book. It is "Lothian Geology An Excursion Guide" by A D McAdam & E N K Clarkson, ISBN 0 904440 06 0.
Here is what it says:
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7. Hilderston Mine: Silver-Lead-Zinc Mineralisation
Park in the lay-by for Cairnpapple at the top of the hill (989 718). Immediately west of the road, the quartz-dolerite sill of localities 3 and 6 crops out forming a good N-S feature some 40m wide. The sill dips steeply to the east as at The Knock, and is really a ****-like step between levels of sill. A diversion may be made at this point to the bronze-age burial mound of Cairnpapple Hill, 250m to the south-west, which is also a good viewpoint.
Folow the sill/**** southward into the valley to the ruins of Windywa's which are on the site of the original 17th century Hilderston silver mine (Cadell 1925; Stephenson 1983). The mine was in operation initially from 1606 to 1614 but made little or no profit after the first two years (i.e. after it had been 'nationalised' by King James VI). The silver occurred in a vein as filaments of native silver in a gangue of baryte and niccolite. The vein was located on the margin of a thin E-W dolerite **** which cut sandstones and siltstones above the Petershill Limestone. The economic vein extended for only 80 m to the east of the N-S ****/sill and for 18 m below the surface. In the 18th century the mine was reopened and worked for lead and zinc which occurred within a baryte and calcite gangue at deeper levels, where the vein cut the Petershill Limestone. A second, much longer vein, some 60 m to the north, was also worked at this time, but this phase of working ceased in 1722. The original workings wree re-excavated during the period 1865 to 1873 using money from the sale of the niccolite and again from 1896 to 1898. However, no further economic deposits of silver or lead were discovered.
The full list of known minerals from the mine is: baryte, calcite, dolomite, quartz, galena, sphalerite, niccolite, erythrite (nickel bloom), annabergite (solid hydrocarbon) and native silver. Most of these, with the exception of the nickel, cobalt and silver minerals, have been obtained recently from the waste heaps.
Three depressions close to the road at Windywa's mark the site of the main group of 17th century shafts. A large mound in the field east of the road marks the main 18th century shaft on the northern lead vein. The 1873 shaft is probably marked by a pile of debris, crescentic in plan, south of the burn and 35 m east of the road. Two adits in the west wall of the flooded Silvermines quarry mark two branches of the northern lead vein, probably excavated in the 19th century. If the water level is low, these adits can be examined. Do not enter them. Thin calcite veins with galena can be seen cutting the sandstone roof of the northernmost one.
The Petershill Limestone is no longer visible in the quarries, but the overlying clastic sediments can be examined in the cut to the south. Here an upward-coarsening sequence of clasyic sediments can be seen with mudstone at the base of the quarry, gradually passing upwards to sandstone at the top. Fallen sandstone blocks at the foot of the quarry show good examples of trace fossils, both burrows and feeding trails. This type of upward-coarsening succession is typical of that associated with deltaic sedimentation. A thin N-S tholeiite **** in the west wall of the southern quarry is altered to 'white trap' at its northern end.
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Well, that does seem to be King Jamie's mine, and there should be two adits.
Just in case there are any copyright fascists reading this, I would point out that short extracts from a work are permitted, for purposes such as criticism. This being a mine exploration forum, there is one sentence which I think we will criticise.....
But there are anomalies. The shaft at 297912,671491
on the 25000 map on Streetmap, surely one of the silver shafts, is shown as "Old Coal Pit" on old-maps.co.uk, as are those around Ballencrief mains to the west. But someweere else, I read a while back that that is the location of the silver mine. I will try to find that article.
Alan